diff --git a/docs/generators.md b/docs/generators.md
index 40b42004e3..340ff7c5a4 100644
--- a/docs/generators.md
+++ b/docs/generators.md
@@ -1,50 +1,125 @@
 <a id="top"></a>
 # Data Generators
 
-_Generators are currently considered an experimental feature and their
-API can change between versions freely._
-
 Data generators (also known as _data driven/parametrized test cases_)
 let you reuse the same set of assertions across different input values.
 In Catch2, this means that they respect the ordering and nesting
-of the `TEST_CASE` and `SECTION` macros.
-
-How does combining generators and test cases work might be better
-explained by an example:
+of the `TEST_CASE` and `SECTION` macros, and their nested sections
+are run once per each value in a generator.
 
+This is best explained with an example:
 ```cpp
 TEST_CASE("Generators") {
-    auto i = GENERATE( range(1, 11) );
+    auto i = GENERATE(1, 2, 3);
+    SECTION("one") {
+        auto j = GENERATE( -3, -2, -1 );
+        REQUIRE(j < i);
+    }
+}
+```
+
+The assertion in this test case will be run 9 times, because there
+are 3 possible values for `i` (1, 2, and 3) and there are 3 possible
+values for `j` (-3, -2, and -1).
+
+
+There are 2 parts to generators in Catch2, the `GENERATE` macro together
+with the already provided generators, and the `IGenerator<T>` interface
+that allows users to implement their own generators.
+
+## Provided generators
+
+Catch2's provided generator functionality consists of three parts,
+
+* `GENERATE` macro,  that serves to integrate generator expression with
+a test case,
+* 2 fundamental generators
+  * `ValueGenerator<T>` -- contains only single element
+  * `ValuesGenerator<T>` -- contains multiple elements
+* 4 generic generators that modify other generators
+  * `FilterGenerator<T, Predicate>` -- filters out elements from a generator
+  for which the predicate returns "false"
+  * `TakeGenerator<T>` -- takes first `n` elements from a generator
+  * `RepeatGenerator<T>` -- repeats output from a generator `n` times
+  * `MapGenerator<T, U, Func>` -- returns the result of applying `Func`
+  on elements from a different generator
+
+The generators also have associated helper functions that infer their
+type, making their usage much nicer. These are
+
+* `value(T&&)` for `ValueGenerator<T>`
+* `values(std::initializer_list<T>)` for `ValuesGenerator<T>`
+* `filter(predicate, GeneratorWrapper<T>&&)` for `FilterGenerator<T, Predicate>`
+* `take(count, GeneratorWrapper<T>&&)` for `TakeGenerator<T>`
+* `repeat(repeats, GeneratorWrapper<T>&&)` for `RepeatGenerator<T>`
+* `map(func, GeneratorWrapper<T>&&)` for `MapGenerator<T, T, Func>` (map `T` to `T`)
+* `map<T>(func, GeneratorWrapper<U>&&)` for `MapGenerator<T, U, Func>` (map `U` to `T`)
 
-    SECTION( "Some section" ) {
-        auto j = GENERATE( range( 11, 21 ) );
-        REQUIRE(i < j);
+And can be used as shown in the example below to create a generator
+that returns 100 odd random number:
+
+```cpp
+TEST_CASE("Generating random ints", "[example][generator]") {
+    SECTION("Deducing functions") {
+        auto i = GENERATE(take(100, filter([](int i) { return i % 2 == 1; }, random(-100, 100))));
+        REQUIRE(i > -100);
+        REQUIRE(i < 100);
+        REQUIRE(i % 2 == 1);
     }
 }
 ```
 
-the assertion will be checked 100 times, because there are 10 possible
-values for `i` (1, 2, ..., 10) and for each of them, there are 10 possible
-values for `j` (11, 12, ..., 20).
+_Note that `random` is currently not a part of the first-party generators_.
+
+
+Apart from registering generators with Catch2, the `GENERATE` macro has
+one more purpose, and that is to provide simple way of generating trivial
+generators, as seen in the first example on this page, where we used it
+as `auto i = GENERATE(1, 2, 3);`. This usage converted each of the three
+literals into a single `ValueGenerator<int>` and then placed them all in
+a special generator that concatenates other generators. It can also be
+used with other generators as arguments, such as `auto i = GENERATE(0, 2,
+take(100, random(300, 3000)));`. This is useful e.g. if you know that
+specific inputs are problematic and want to test them separately/first.
+
+**For safety reasons, you cannot use variables inside the `GENERATE` macro.**
+
+You can also override the inferred type by using `as<type>` as the first
+argument to the macro. This can be useful when dealing with string literals,
+if you want them to come out as `std::string`:
 
-You can also combine multiple generators by concatenation:
 ```cpp
-static int square(int x) { return x * x; }
-TEST_CASE("Generators 2") {
-    auto i = GENERATE(0, 1, -1, range(-20, -10), range(10, 20));
-    CAPTURE(i);
-    REQUIRE(square(i) >= 0);
+TEST_CASE("type conversion", "[generators]") {
+    auto str = GENERATE(as<std::string>{}, "a", "bb", "ccc");`
+    REQUIRE(str.size() > 0);
 }
 ```
 
-This will call `square` with arguments `0`, `1`, `-1`, `-20`, ..., `-11`,
-`10`, ..., `19`.
+## Generator interface
+
+You can also implement your own generators, by deriving from the
+`IGenerator<T>` interface:
+
+```cpp
+template<typename T>
+struct IGenerator : GeneratorUntypedBase {
+    // via GeneratorUntypedBase:
+    // Attempts to move the generator to the next element.
+    // Returns true if successful (and thus has another element that can be read)
+    virtual bool next() = 0;
+
+    // Precondition:
+    // The generator is either freshly constructed or the last call to next() returned true
+    virtual T const& get() const = 0;
+};
+```
+
+However, to be able to use your custom generator inside `GENERATE`, it
+will need to be wrapped inside a `GeneratorWrapper<T>`.
+`GeneratorWrapper<T>` is a value wrapper around a
+`std::unique_ptr<IGenerator<T>>`.
 
-----------
+For full example of implementing your own generator, look into Catch2's
+examples, specifically
+[Generators: Create your own generator](../examples/300-Gen-OwnGenerator.cpp).
 
-Because of the experimental nature of the current Generator implementation,
-we won't list all of the first-party generators in Catch2. Instead you
-should look at our current usage tests in
-[projects/SelfTest/UsageTests/Generators.tests.cpp](/projects/SelfTest/UsageTests/Generators.tests.cpp).
-For implementing your own generators, you can look at their implementation in
-[include/internal/catch_generators.hpp](/include/internal/catch_generators.hpp).
diff --git a/docs/list-of-examples.md b/docs/list-of-examples.md
index 5b538da032..c1aa78a19b 100644
--- a/docs/list-of-examples.md
+++ b/docs/list-of-examples.md
@@ -14,6 +14,9 @@
 - Report: [TeamCity reporter](../examples/207-Rpt-TeamCityReporter.cpp)
 - Listener: [Listeners](../examples/210-Evt-EventListeners.cpp)
 - Configuration: [Provide your own output streams](../examples/231-Cfg-OutputStreams.cpp)
+- Generators: [Create your own generator](../examples/300-Gen-OwnGenerator.cpp)
+- Generators: [Use variables in generator expressions](../examples/310-Gen-VariablesInGenerators.cpp)
+
 
 ## Planned
 
diff --git a/examples/300-Gen-OwnGenerator.cpp b/examples/300-Gen-OwnGenerator.cpp
new file mode 100644
index 0000000000..c8b6a65df7
--- /dev/null
+++ b/examples/300-Gen-OwnGenerator.cpp
@@ -0,0 +1,59 @@
+// 300-Gen-OwnGenerator.cpp
+// Shows how to define a custom generator.
+
+// Specifically we will implement a random number generator for integers
+// It will have infinite capacity and settable lower/upper bound
+
+#include <catch2/catch.hpp>
+
+#include <random>
+
+// This class shows how to implement a simple generator for Catch tests
+class RandomIntGenerator : public Catch::Generators::IGenerator<int> {
+    std::minstd_rand m_rand;
+    std::uniform_int_distribution<> m_dist;
+    int current_number;
+public:
+
+    RandomIntGenerator(int low, int high):
+        m_rand(std::random_device{}()),
+        m_dist(low, high)
+    {
+        static_cast<void>(next());
+    }
+
+    int const& get() const override;
+    bool next() override {
+        current_number = m_dist(m_rand);
+        return true;
+    }
+};
+
+// Avoids -Wweak-vtables
+int const& RandomIntGenerator::get() const {
+    return current_number;
+}
+
+// This helper function provides a nicer UX when instantiating the generator
+// Notice that it returns an instance of GeneratorWrapper<int>, which
+// is a value-wrapper around std::unique_ptr<IGenerator<int>>.
+Catch::Generators::GeneratorWrapper<int> random(int low, int high) {
+    return Catch::Generators::GeneratorWrapper<int>(std::unique_ptr<Catch::Generators::IGenerator<int>>(new RandomIntGenerator(low, high)));
+}
+
+// The two sections in this test case are equivalent, but the first one
+// is much more readable/nicer to use
+TEST_CASE("Generating random ints", "[example][generator]") {
+    SECTION("Nice UX") {
+        auto i = GENERATE(take(100, random(-100, 100)));
+        REQUIRE(i >= -100);
+        REQUIRE(i <= 100);
+    }
+    SECTION("Creating the random generator directly") {
+        auto i = GENERATE(take(100, GeneratorWrapper<int>(std::unique_ptr<IGenerator<int>>(new RandomIntGenerator(-100, 100)))));
+        REQUIRE(i >= -100);
+        REQUIRE(i <= 100);
+    }
+}
+
+// Compiling and running this file will result in 400 successful assertions
diff --git a/examples/310-Gen-VariablesInGenerators.cpp b/examples/310-Gen-VariablesInGenerators.cpp
new file mode 100644
index 0000000000..96840bbbe4
--- /dev/null
+++ b/examples/310-Gen-VariablesInGenerators.cpp
@@ -0,0 +1,72 @@
+// 310-Gen-VariablesInGenerator.cpp
+// Shows how to use variables when creating generators.
+
+// Note that using variables inside generators is dangerous and should
+// be done only if you know what you are doing, because the generators
+// _WILL_ outlive the variables -- thus they should be either captured
+// by value directly, or copied by the generators during construction.
+
+#include <catch2/catch.hpp>
+
+#include <random>
+
+// Lets start by implementing a parametrizable double generator
+class RandomDoubleGenerator : public Catch::Generators::IGenerator<double> {
+    std::minstd_rand m_rand;
+    std::uniform_real_distribution<> m_dist;
+    double current_number;
+public:
+
+    RandomDoubleGenerator(double low, double high):
+        m_rand(std::random_device{}()),
+        m_dist(low, high)
+    {
+        static_cast<void>(next());
+    }
+
+    double const& get() const override;
+    bool next() override {
+        current_number = m_dist(m_rand);
+        return true;
+    }
+};
+
+// Avoids -Wweak-vtables
+double const& RandomDoubleGenerator::get() const {
+    return current_number;
+}
+
+
+// Also provide a nice shortcut for creating the generator
+Catch::Generators::GeneratorWrapper<double> random(double low, double high) {
+    return Catch::Generators::GeneratorWrapper<double>(std::unique_ptr<Catch::Generators::IGenerator<double>>(new RandomDoubleGenerator(low, high)));
+}
+
+
+TEST_CASE("Generate random doubles across different ranges",
+          "[generator][example][advanced]") {
+    // Workaround for old libstdc++
+    using record = std::tuple<double, double>;
+    // Set up 3 ranges to generate numbers from
+    auto r = GENERATE(table<double, double>({
+        record{3, 4},
+        record{-4, -3},
+        record{10, 1000}
+    }));
+
+    // This will not compile (intentionally), because it accesses a variable
+    // auto number = GENERATE(take(50, random(r.first, r.second)));
+    
+    // We have to manually register the generators instead
+    // Notice that we are using value capture in the lambda, to avoid lifetime issues
+    auto number = Catch::Generators::generate( CATCH_INTERNAL_LINEINFO,
+        [=]{
+            using namespace Catch::Generators;
+            return makeGenerators(take(50, random(std::get<0>(r), std::get<1>(r))));
+        }
+    );
+    REQUIRE(std::abs(number) > 0);
+}
+
+// Compiling and running this file will result in 150 successful assertions
+
diff --git a/examples/CMakeLists.txt b/examples/CMakeLists.txt
index 2551e77c07..0eea900de5 100644
--- a/examples/CMakeLists.txt
+++ b/examples/CMakeLists.txt
@@ -44,6 +44,8 @@ set( SOURCES_IDIOMATIC_TESTS
     110-Fix-ClassFixture.cpp
     120-Bdd-ScenarioGivenWhenThen.cpp
     210-Evt-EventListeners.cpp
+    300-Gen-OwnGenerator.cpp
+    310-Gen-VariablesInGenerators.cpp
 )
 
 # main-s for reporter-specific test sources:
diff --git a/include/internal/catch_generators.cpp b/include/internal/catch_generators.cpp
index 786da73675..5fbe2d2384 100644
--- a/include/internal/catch_generators.cpp
+++ b/include/internal/catch_generators.cpp
@@ -16,35 +16,17 @@ namespace Catch {
 
 IGeneratorTracker::~IGeneratorTracker() {}
 
-namespace Generators {
-
-    GeneratorBase::~GeneratorBase() {}
+const char* GeneratorException::what() const noexcept {
+    return m_msg;
+}
 
-    std::vector<size_t> randomiseIndices( size_t selectionSize, size_t sourceSize ) {
+namespace Generators {
 
-        assert( selectionSize <= sourceSize );
-        std::vector<size_t> indices;
-        indices.reserve( selectionSize );
-        std::uniform_int_distribution<size_t> uid( 0, sourceSize-1 );
-
-        std::set<size_t> seen;
-        // !TBD: improve this algorithm
-        while( indices.size() < selectionSize ) {
-            auto index = uid( rng() );
-            if( seen.insert( index ).second )
-                indices.push_back( index );
-        }
-        return indices;
-    }
+    GeneratorUntypedBase::~GeneratorUntypedBase() {}
 
     auto acquireGeneratorTracker( SourceLineInfo const& lineInfo ) -> IGeneratorTracker& {
         return getResultCapture().acquireGeneratorTracker( lineInfo );
     }
 
-    template<>
-    auto all<int>() -> Generator<int> {
-        return range( std::numeric_limits<int>::min(), std::numeric_limits<int>::max() );
-    }
-
 } // namespace Generators
 } // namespace Catch
diff --git a/include/internal/catch_generators.hpp b/include/internal/catch_generators.hpp
index 4a446be131..f7dbc8c7f4 100644
--- a/include/internal/catch_generators.hpp
+++ b/include/internal/catch_generators.hpp
@@ -16,8 +16,21 @@
 #include <cassert>
 
 #include <utility>
+#include <exception>
 
 namespace Catch {
+
+class GeneratorException : public std::exception {
+    const char* const m_msg = "";
+
+public:
+    GeneratorException(const char* msg):
+        m_msg(msg)
+    {}
+
+    const char* what() const noexcept override final;
+};
+
 namespace Generators {
 
     // !TBD move this into its own location?
@@ -29,218 +42,329 @@ namespace Generators {
     }
 
     template<typename T>
-    struct IGenerator {
-        virtual ~IGenerator() {}
-        virtual auto get( size_t index ) const -> T = 0;
+    struct IGenerator : GeneratorUntypedBase {
+        virtual ~IGenerator() = default;
+
+        // Returns the current element of the generator
+        //
+        // \Precondition The generator is either freshly constructed,
+        // or the last call to `next()` returned true
+        virtual T const& get() const = 0;
+        using type = T;
     };
 
     template<typename T>
-    class SingleValueGenerator : public IGenerator<T> {
+    class SingleValueGenerator final : public IGenerator<T> {
         T m_value;
     public:
-        SingleValueGenerator( T const& value ) : m_value( value ) {}
+        SingleValueGenerator(T const& value) : m_value( value ) {}
+        SingleValueGenerator(T&& value) : m_value(std::move(value)) {}
 
-        auto get( size_t ) const -> T override {
+        T const& get() const override {
             return m_value;
         }
+        bool next() override {
+            return false;
+        }
     };
 
     template<typename T>
-    class FixedValuesGenerator : public IGenerator<T> {
+    class FixedValuesGenerator final : public IGenerator<T> {
         std::vector<T> m_values;
-
+        size_t m_idx = 0;
     public:
         FixedValuesGenerator( std::initializer_list<T> values ) : m_values( values ) {}
 
-        auto get( size_t index ) const -> T override {
-            return m_values[index];
+        T const& get() const override {
+            return m_values[m_idx];
+        }
+        bool next() override {
+            ++m_idx;
+            return m_idx < m_values.size();
         }
     };
 
-    template<typename T>
-    class RangeGenerator : public IGenerator<T> {
-        T const m_first;
-        T const m_last;
-
+    template <typename T>
+    class GeneratorWrapper final {
+        std::unique_ptr<IGenerator<T>> m_generator;
     public:
-        RangeGenerator( T const& first, T const& last ) : m_first( first ), m_last( last ) {
-            assert( m_last > m_first );
+        GeneratorWrapper(std::unique_ptr<IGenerator<T>> generator):
+            m_generator(std::move(generator))
+        {}
+        T const& get() const {
+            return m_generator->get();
         }
-
-        auto get( size_t index ) const -> T override {
-            // ToDo:: introduce a safe cast to catch potential overflows
-            return static_cast<T>(m_first+index);
+        bool next() {
+            return m_generator->next();
         }
     };
 
+    template <typename T>
+    GeneratorWrapper<T> value(T&& value) {
+        return GeneratorWrapper<T>(pf::make_unique<SingleValueGenerator<T>>(std::forward<T>(value)));
+    }
+    template <typename T>
+    GeneratorWrapper<T> values(std::initializer_list<T> values) {
+        return GeneratorWrapper<T>(pf::make_unique<FixedValuesGenerator<T>>(values));
+    }
 
     template<typename T>
-    struct NullGenerator : IGenerator<T> {
-        auto get( size_t ) const -> T override {
-            CATCH_INTERNAL_ERROR("A Null Generator is always empty");
-        }
-    };
+    class Generators : public IGenerator<T> {
+        std::vector<GeneratorWrapper<T>> m_generators;
+        size_t m_current = 0;
 
-    template<typename T>
-    class Generator {
-        std::unique_ptr<IGenerator<T>> m_generator;
-        size_t m_size;
+        void populate(GeneratorWrapper<T>&& generator) {
+            m_generators.emplace_back(std::move(generator));
+        }
+        void populate(T&& val) {
+            m_generators.emplace_back(value(std::move(val)));
+        }
+        template<typename U>
+        void populate(U&& val) {
+            populate(T(std::move(val)));
+        }
+        template<typename U, typename... Gs>
+        void populate(U&& valueOrGenerator, Gs... moreGenerators) {
+            populate(std::forward<U>(valueOrGenerator));
+            populate(std::forward<Gs>(moreGenerators)...);
+        }
 
     public:
-        Generator( size_t size, std::unique_ptr<IGenerator<T>> generator )
-        :   m_generator( std::move( generator ) ),
-            m_size( size )
-        {}
-
-        auto size() const -> size_t { return m_size; }
-        auto operator[]( size_t index ) const -> T {
-            assert( index < m_size );
-            return m_generator->get( index );
+        template <typename... Gs>
+        Generators(Gs... moreGenerators) {
+            m_generators.reserve(sizeof...(Gs));
+            populate(std::forward<Gs>(moreGenerators)...);
         }
-    };
 
-    std::vector<size_t> randomiseIndices( size_t selectionSize, size_t sourceSize );
-
-    template<typename T>
-    class GeneratorRandomiser : public IGenerator<T> {
-        Generator<T> m_baseGenerator;
-
-        std::vector<size_t> m_indices;
-    public:
-        GeneratorRandomiser( Generator<T>&& baseGenerator, size_t numberOfItems )
-        :   m_baseGenerator( std::move( baseGenerator ) ),
-            m_indices( randomiseIndices( numberOfItems, m_baseGenerator.size() ) )
-        {}
+        T const& get() const override {
+            return m_generators[m_current].get();
+        }
 
-        auto get( size_t index ) const -> T override {
-            return m_baseGenerator[m_indices[index]];
+        bool next() override {
+            if (m_current >= m_generators.size()) {
+                return false;
+            }
+            const bool current_status = m_generators[m_current].next();
+            if (!current_status) {
+                ++m_current;
+            }
+            return m_current < m_generators.size();
         }
     };
 
-    template<typename T>
-    struct RequiresASpecialisationFor;
-
-    template<typename T>
-    auto all() -> Generator<T> { return RequiresASpecialisationFor<T>(); }
-
-    template<>
-    auto all<int>() -> Generator<int>;
-
 
-    template<typename T>
-    auto range( T const& first, T const& last ) -> Generator<T> {
-        return Generator<T>( (last-first), pf::make_unique<RangeGenerator<T>>( first, last ) );
+    template<typename... Ts>
+    GeneratorWrapper<std::tuple<Ts...>> table( std::initializer_list<std::tuple<typename std::decay<Ts>::type...>> tuples ) {
+        return values<std::tuple<Ts...>>( tuples );
     }
 
-    template<typename T>
-    auto random( T const& first, T const& last ) -> Generator<T> {
-        auto gen = range( first, last );
-        auto size = gen.size();
+    // Tag type to signal that a generator sequence should convert arguments to a specific type
+    template <typename T>
+    struct as {};
 
-        return Generator<T>( size, pf::make_unique<GeneratorRandomiser<T>>( std::move( gen ), size ) );
+    template<typename T, typename... Gs>
+    auto makeGenerators( GeneratorWrapper<T>&& generator, Gs... moreGenerators ) -> Generators<T> {
+        return Generators<T>(std::move(generator), std::forward<Gs>(moreGenerators)...);
     }
     template<typename T>
-    auto random( size_t size ) -> Generator<T> {
-        return Generator<T>( size, pf::make_unique<GeneratorRandomiser<T>>( all<T>(), size ) );
+    auto makeGenerators( GeneratorWrapper<T>&& generator ) -> Generators<T> {
+        return Generators<T>(std::move(generator));
     }
-
-    template<typename T>
-    auto values( std::initializer_list<T> values ) -> Generator<T> {
-        return Generator<T>( values.size(), pf::make_unique<FixedValuesGenerator<T>>( values ) );
+    template<typename T, typename... Gs>
+    auto makeGenerators( T&& val, Gs... moreGenerators ) -> Generators<T> {
+        return makeGenerators( value( std::forward<T>( val ) ), std::forward<Gs>( moreGenerators )... );
     }
-    template<typename T>
-    auto value( T const& val ) -> Generator<T> {
-        return Generator<T>( 1, pf::make_unique<SingleValueGenerator<T>>( val ) );
+    template<typename T, typename U, typename... Gs>
+    auto makeGenerators( as<T>, U&& val, Gs... moreGenerators ) -> Generators<T> {
+        return makeGenerators( value( T( std::forward<U>( val ) ) ), std::forward<Gs>( moreGenerators )... );
     }
 
-    template<typename T>
-    auto as() -> Generator<T> {
-        return Generator<T>( 0, pf::make_unique<NullGenerator<T>>() );
-    }
+    template <typename T>
+    class TakeGenerator : public IGenerator<T> {
+        GeneratorWrapper<T> m_generator;
+        size_t m_returned = 0;
+        size_t m_target;
+    public:
+        TakeGenerator(size_t target, GeneratorWrapper<T>&& generator):
+            m_generator(std::move(generator)),
+            m_target(target)
+        {
+            assert(target != 0 && "Empty generators are not allowed");
+        }
+        T const& get() const override {
+            return m_generator.get();
+        }
+        bool next() override {
+            ++m_returned;
+            if (m_returned >= m_target) {
+                return false;
+            }
 
-    template<typename... Ts>
-    auto table( std::initializer_list<std::tuple<Ts...>>&& tuples ) -> Generator<std::tuple<Ts...>> {
-        return values<std::tuple<Ts...>>( std::forward<std::initializer_list<std::tuple<Ts...>>>( tuples ) );
-    }
+            const auto success = m_generator.next();
+            // If the underlying generator does not contain enough values
+            // then we cut short as well
+            if (!success) {
+                m_returned = m_target;
+            }
+            return success;
+        }
+    };
 
+    template <typename T>
+    GeneratorWrapper<T> take(size_t target, GeneratorWrapper<T>&& generator) {
+        return GeneratorWrapper<T>(pf::make_unique<TakeGenerator<T>>(target, std::move(generator)));
+    }
 
-    template<typename T>
-    struct Generators : GeneratorBase {
-        std::vector<Generator<T>> m_generators;
 
-        using type = T;
+    template <typename T, typename Predicate>
+    class FilterGenerator : public IGenerator<T> {
+        GeneratorWrapper<T> m_generator;
+        Predicate m_predicate;
+    public:
+        template <typename P = Predicate>
+        FilterGenerator(P&& pred, GeneratorWrapper<T>&& generator):
+            m_generator(std::move(generator)),
+            m_predicate(std::forward<P>(pred))
+        {
+            if (!m_predicate(m_generator.get())) {
+                // It might happen that there are no values that pass the
+                // filter. In that case we throw an exception.
+                auto has_initial_value = next();
+                if (!has_initial_value) {
+                    Catch::throw_exception(GeneratorException("No valid value found in filtered generator"));
+                }
+            }
+        }
 
-        Generators() : GeneratorBase( 0 ) {}
+        T const& get() const override {
+            return m_generator.get();
+        }
 
-        void populate( T&& val ) {
-            m_size += 1;
-            m_generators.emplace_back( value( std::move( val ) ) );
+        bool next() override {
+            bool success = m_generator.next();
+            if (!success) {
+                return false;
+            }
+            while (!m_predicate(m_generator.get()) && (success = m_generator.next()) == true);
+            return success;
         }
-        template<typename U>
-        void populate( U&& val ) {
-            populate( T( std::move( val ) ) );
+    };
+
+
+    template <typename T, typename Predicate>
+    GeneratorWrapper<T> filter(Predicate&& pred, GeneratorWrapper<T>&& generator) {
+        return GeneratorWrapper<T>(std::unique_ptr<IGenerator<T>>(pf::make_unique<FilterGenerator<T, Predicate>>(std::forward<Predicate>(pred), std::move(generator))));
+    }
+
+    template <typename T>
+    class RepeatGenerator : public IGenerator<T> {
+        GeneratorWrapper<T> m_generator;
+        mutable std::vector<T> m_returned;
+        size_t m_target_repeats;
+        size_t m_current_repeat = 0;
+        size_t m_repeat_index = 0;
+    public:
+        RepeatGenerator(size_t repeats, GeneratorWrapper<T>&& generator):
+            m_generator(std::move(generator)),
+            m_target_repeats(repeats)
+        {
+            assert(m_target_repeats > 0 && "Repeat generator must repeat at least once");
         }
-        void populate( Generator<T>&& generator ) {
-            m_size += generator.size();
-            m_generators.emplace_back( std::move( generator ) );
+
+        T const& get() const override {
+            if (m_current_repeat == 0) {
+                m_returned.push_back(m_generator.get());
+                return m_returned.back();
+            }
+            return m_returned[m_repeat_index];
         }
 
-        template<typename U, typename... Gs>
-        void populate( U&& valueOrGenerator, Gs... moreGenerators ) {
-            populate( std::forward<U>( valueOrGenerator ) );
-            populate( std::forward<Gs>( moreGenerators )... );
-        }
-
-        auto operator[]( size_t index ) const -> T {
-            size_t sizes = 0;
-            for( auto const& gen : m_generators ) {
-                auto localIndex = index-sizes;
-                sizes += gen.size();
-                if( index < sizes )
-                    return gen[localIndex];
+        bool next() override {
+            // There are 2 basic cases:
+            // 1) We are still reading the generator
+            // 2) We are reading our own cache
+
+            // In the first case, we need to poke the underlying generator.
+            // If it happily moves, we are left in that state, otherwise it is time to start reading from our cache
+            if (m_current_repeat == 0) {
+                const auto success = m_generator.next();
+                if (!success) {
+                    ++m_current_repeat;
+                }
+                return m_current_repeat < m_target_repeats;
             }
-            CATCH_INTERNAL_ERROR("Index '" << index << "' is out of range (" << sizes << ')');
+
+            // In the second case, we need to move indices forward and check that we haven't run up against the end
+            ++m_repeat_index;
+            if (m_repeat_index == m_returned.size()) {
+                m_repeat_index = 0;
+                ++m_current_repeat;
+            }
+            return m_current_repeat < m_target_repeats;
         }
     };
 
-    template<typename T, typename... Gs>
-    auto makeGenerators( Generator<T>&& generator, Gs... moreGenerators ) -> Generators<T> {
-        Generators<T> generators;
-        generators.m_generators.reserve( 1+sizeof...(Gs) );
-        generators.populate( std::move( generator ), std::forward<Gs>( moreGenerators )... );
-        return generators;
+    template <typename T>
+    GeneratorWrapper<T> repeat(size_t repeats, GeneratorWrapper<T>&& generator) {
+        return GeneratorWrapper<T>(pf::make_unique<RepeatGenerator<T>>(repeats, std::move(generator)));
     }
-    template<typename T>
-    auto makeGenerators( Generator<T>&& generator ) -> Generators<T> {
-        Generators<T> generators;
-        generators.populate( std::move( generator ) );
-        return generators;
-    }
-    template<typename T, typename... Gs>
-    auto makeGenerators( T&& val, Gs... moreGenerators ) -> Generators<T> {
-        return makeGenerators( value( std::forward<T>( val ) ), std::forward<Gs>( moreGenerators )... );
+
+    template <typename T, typename U, typename Func>
+    class MapGenerator : public IGenerator<T> {
+        // TBD: provide static assert for mapping function, for friendly error message
+        GeneratorWrapper<U> m_generator;
+        Func m_function;
+        // To avoid returning dangling reference, we have to save the values
+        T m_cache;
+    public:
+        template <typename F2 = Func>
+        MapGenerator(F2&& function, GeneratorWrapper<U>&& generator) :
+            m_generator(std::move(generator)),
+            m_function(std::forward<F2>(function)),
+            m_cache(m_function(m_generator.get()))
+        {}
+
+        T const& get() const override {
+            return m_cache;
+        }
+        bool next() override {
+            const auto success = m_generator.next();
+            if (success) {
+                m_cache = m_function(m_generator.get());
+            }
+            return success;
+        }
+    };
+
+    template <typename T, typename U, typename Func>
+    GeneratorWrapper<T> map(Func&& function, GeneratorWrapper<U>&& generator) {
+        return GeneratorWrapper<T>(
+            pf::make_unique<MapGenerator<T, U, Func>>(std::forward<Func>(function), std::move(generator))
+        );
     }
-    template<typename T, typename U, typename... Gs>
-    auto makeGenerators( U&& val, Gs... moreGenerators ) -> Generators<T> {
-        return makeGenerators( value( T( std::forward<U>( val ) ) ), std::forward<Gs>( moreGenerators )... );
+    template <typename T, typename Func>
+    GeneratorWrapper<T> map(Func&& function, GeneratorWrapper<T>&& generator) {
+        return GeneratorWrapper<T>(
+            pf::make_unique<MapGenerator<T, T, Func>>(std::forward<Func>(function), std::move(generator))
+        );
     }
 
-
     auto acquireGeneratorTracker( SourceLineInfo const& lineInfo ) -> IGeneratorTracker&;
 
     template<typename L>
     // Note: The type after -> is weird, because VS2015 cannot parse
     //       the expression used in the typedef inside, when it is in
     //       return type. Yeah, ¯\_(ツ)_/¯
-    auto generate( SourceLineInfo const& lineInfo, L const& generatorExpression ) -> decltype(std::declval<decltype(generatorExpression())>()[0]) {
+    auto generate( SourceLineInfo const& lineInfo, L const& generatorExpression ) -> decltype(std::declval<decltype(generatorExpression())>().get()) {
         using UnderlyingType = typename decltype(generatorExpression())::type;
 
         IGeneratorTracker& tracker = acquireGeneratorTracker( lineInfo );
-        if( !tracker.hasGenerator() )
-            tracker.setGenerator( pf::make_unique<Generators<UnderlyingType>>( generatorExpression() ) );
+        if (!tracker.hasGenerator()) {
+            tracker.setGenerator(pf::make_unique<Generators<UnderlyingType>>(generatorExpression()));
+        }
 
-        auto const& generator = static_cast<Generators<UnderlyingType> const&>( *tracker.getGenerator() );
-        return generator[tracker.getIndex()];
+        auto const& generator = static_cast<IGenerator<UnderlyingType> const&>( *tracker.getGenerator() );
+        return generator.get();
     }
 
 } // namespace Generators
diff --git a/include/internal/catch_interfaces_generatortracker.h b/include/internal/catch_interfaces_generatortracker.h
index 2cf6269e4d..c1b1391ff1 100644
--- a/include/internal/catch_interfaces_generatortracker.h
+++ b/include/internal/catch_interfaces_generatortracker.h
@@ -13,16 +13,17 @@
 namespace Catch {
 
     namespace Generators {
-        class GeneratorBase {
-        protected:
-            size_t m_size = 0;
-
+        class GeneratorUntypedBase {
         public:
-            GeneratorBase( size_t size ) : m_size( size ) {}
-            virtual ~GeneratorBase();
-            auto size() const -> size_t { return m_size; }
+            GeneratorUntypedBase() = default;
+            virtual ~GeneratorUntypedBase();
+            // Attempts to move the generator to the next element
+             //
+             // Returns true iff the move succeeded (and a valid element
+             // can be retrieved).
+            virtual bool next() = 0;
         };
-        using GeneratorBasePtr = std::unique_ptr<GeneratorBase>;
+        using GeneratorBasePtr = std::unique_ptr<GeneratorUntypedBase>;
 
     } // namespace Generators
 
@@ -31,7 +32,6 @@ namespace Catch {
         virtual auto hasGenerator() const -> bool = 0;
         virtual auto getGenerator() const -> Generators::GeneratorBasePtr const& = 0;
         virtual void setGenerator( Generators::GeneratorBasePtr&& generator ) = 0;
-        virtual auto getIndex() const -> std::size_t = 0;
     };
 
 } // namespace Catch
diff --git a/include/internal/catch_run_context.cpp b/include/internal/catch_run_context.cpp
index ffdd2ebbf6..77dcaae072 100644
--- a/include/internal/catch_run_context.cpp
+++ b/include/internal/catch_run_context.cpp
@@ -14,7 +14,6 @@ namespace Catch {
 
     namespace Generators {
         struct GeneratorTracker : TestCaseTracking::TrackerBase, IGeneratorTracker {
-            size_t m_index = static_cast<size_t>( -1 );
             GeneratorBasePtr m_generator;
 
             GeneratorTracker( TestCaseTracking::NameAndLocation const& nameAndLocation, TrackerContext& ctx, ITracker* parent )
@@ -28,7 +27,7 @@ namespace Catch {
                 ITracker& currentTracker = ctx.currentTracker();
                 if( TestCaseTracking::ITrackerPtr childTracker = currentTracker.findChild( nameAndLocation ) ) {
                     assert( childTracker );
-                    assert( childTracker->isIndexTracker() );
+                    assert( childTracker->isGeneratorTracker() );
                     tracker = std::static_pointer_cast<GeneratorTracker>( childTracker );
                 }
                 else {
@@ -37,28 +36,24 @@ namespace Catch {
                 }
 
                 if( !ctx.completedCycle() && !tracker->isComplete() ) {
-                    if( tracker->m_runState != ExecutingChildren && tracker->m_runState != NeedsAnotherRun )
-                        tracker->moveNext();
                     tracker->open();
                 }
 
                 return *tracker;
             }
 
-            void moveNext() {
-                m_index++;
-                m_children.clear();
-            }
-
             // TrackerBase interface
-            bool isIndexTracker() const override { return true; }
+            bool isGeneratorTracker() const override { return true; }
             auto hasGenerator() const -> bool override {
                 return !!m_generator;
             }
             void close() override {
                 TrackerBase::close();
-                if( m_runState == CompletedSuccessfully && m_index < m_generator->size()-1 )
+                // Generator interface only finds out if it has another item on atual move
+                if (m_runState == CompletedSuccessfully && m_generator->next()) {
+                    m_children.clear();
                     m_runState = Executing;
+                }
             }
 
             // IGeneratorTracker interface
@@ -68,9 +63,6 @@ namespace Catch {
             void setGenerator( GeneratorBasePtr&& generator ) override {
                 m_generator = std::move( generator );
             }
-            auto getIndex() const -> size_t override {
-                return m_index;
-            }
         };
         GeneratorTracker::~GeneratorTracker() {}
     }
diff --git a/include/internal/catch_test_case_tracker.cpp b/include/internal/catch_test_case_tracker.cpp
index f6e5ac081d..210f273052 100644
--- a/include/internal/catch_test_case_tracker.cpp
+++ b/include/internal/catch_test_case_tracker.cpp
@@ -121,7 +121,7 @@ namespace TestCaseTracking {
     }
 
     bool TrackerBase::isSectionTracker() const { return false; }
-    bool TrackerBase::isIndexTracker() const { return false; }
+    bool TrackerBase::isGeneratorTracker() const { return false; }
 
     void TrackerBase::open() {
         m_runState = Executing;
diff --git a/include/internal/catch_test_case_tracker.h b/include/internal/catch_test_case_tracker.h
index e873d788e2..172760017d 100644
--- a/include/internal/catch_test_case_tracker.h
+++ b/include/internal/catch_test_case_tracker.h
@@ -54,7 +54,7 @@ namespace TestCaseTracking {
 
         // Debug/ checking
         virtual bool isSectionTracker() const = 0;
-        virtual bool isIndexTracker() const = 0;
+        virtual bool isGeneratorTracker() const = 0;
     };
 
     class TrackerContext {
@@ -120,7 +120,7 @@ namespace TestCaseTracking {
         void openChild() override;
 
         bool isSectionTracker() const override;
-        bool isIndexTracker() const override;
+        bool isGeneratorTracker() const override;
 
         void open();
 
diff --git a/projects/SelfTest/Baselines/compact.sw.approved.txt b/projects/SelfTest/Baselines/compact.sw.approved.txt
index 72627f1fb5..615e368b35 100644
--- a/projects/SelfTest/Baselines/compact.sw.approved.txt
+++ b/projects/SelfTest/Baselines/compact.sw.approved.txt
@@ -57,106 +57,87 @@ Tricky.tests.cpp:<line number>: passed: !is_true<false>::value for: true
 Tricky.tests.cpp:<line number>: passed: !!is_true<true>::value for: true
 Tricky.tests.cpp:<line number>: passed: is_true<true>::value for: true
 Tricky.tests.cpp:<line number>: passed: !(is_true<false>::value) for: !false
-Generators.tests.cpp:<line number>: passed: x < y for: 1 < 101
-Generators.tests.cpp:<line number>: passed: x < y for: 1 < 102
-Generators.tests.cpp:<line number>: passed: x < y for: 1 < 103
-Generators.tests.cpp:<line number>: passed: x < y for: 1 < 104
-Generators.tests.cpp:<line number>: passed: x < y for: 1 < 105
-Generators.tests.cpp:<line number>: passed: x < y for: 1 < 106
-Generators.tests.cpp:<line number>: passed: x < y for: 1 < 107
-Generators.tests.cpp:<line number>: passed: x < y for: 1 < 108
-Generators.tests.cpp:<line number>: passed: x < y for: 1 < 109
-Generators.tests.cpp:<line number>: passed: x < y for: 1 < 110
-Generators.tests.cpp:<line number>: passed: x < y for: 2 < 101
-Generators.tests.cpp:<line number>: passed: x < y for: 2 < 102
-Generators.tests.cpp:<line number>: passed: x < y for: 2 < 103
-Generators.tests.cpp:<line number>: passed: x < y for: 2 < 104
-Generators.tests.cpp:<line number>: passed: x < y for: 2 < 105
-Generators.tests.cpp:<line number>: passed: x < y for: 2 < 106
-Generators.tests.cpp:<line number>: passed: x < y for: 2 < 107
-Generators.tests.cpp:<line number>: passed: x < y for: 2 < 108
-Generators.tests.cpp:<line number>: passed: x < y for: 2 < 109
-Generators.tests.cpp:<line number>: passed: x < y for: 2 < 110
-Generators.tests.cpp:<line number>: passed: x < y for: 3 < 101
-Generators.tests.cpp:<line number>: passed: x < y for: 3 < 102
-Generators.tests.cpp:<line number>: passed: x < y for: 3 < 103
-Generators.tests.cpp:<line number>: passed: x < y for: 3 < 104
-Generators.tests.cpp:<line number>: passed: x < y for: 3 < 105
-Generators.tests.cpp:<line number>: passed: x < y for: 3 < 106
-Generators.tests.cpp:<line number>: passed: x < y for: 3 < 107
-Generators.tests.cpp:<line number>: passed: x < y for: 3 < 108
-Generators.tests.cpp:<line number>: passed: x < y for: 3 < 109
-Generators.tests.cpp:<line number>: passed: x < y for: 3 < 110
-Generators.tests.cpp:<line number>: passed: x < y for: 4 < 101
-Generators.tests.cpp:<line number>: passed: x < y for: 4 < 102
-Generators.tests.cpp:<line number>: passed: x < y for: 4 < 103
-Generators.tests.cpp:<line number>: passed: x < y for: 4 < 104
-Generators.tests.cpp:<line number>: passed: x < y for: 4 < 105
-Generators.tests.cpp:<line number>: passed: x < y for: 4 < 106
-Generators.tests.cpp:<line number>: passed: x < y for: 4 < 107
-Generators.tests.cpp:<line number>: passed: x < y for: 4 < 108
-Generators.tests.cpp:<line number>: passed: x < y for: 4 < 109
-Generators.tests.cpp:<line number>: passed: x < y for: 4 < 110
-Generators.tests.cpp:<line number>: passed: x < y for: 5 < 101
-Generators.tests.cpp:<line number>: passed: x < y for: 5 < 102
-Generators.tests.cpp:<line number>: passed: x < y for: 5 < 103
-Generators.tests.cpp:<line number>: passed: x < y for: 5 < 104
-Generators.tests.cpp:<line number>: passed: x < y for: 5 < 105
-Generators.tests.cpp:<line number>: passed: x < y for: 5 < 106
-Generators.tests.cpp:<line number>: passed: x < y for: 5 < 107
-Generators.tests.cpp:<line number>: passed: x < y for: 5 < 108
-Generators.tests.cpp:<line number>: passed: x < y for: 5 < 109
-Generators.tests.cpp:<line number>: passed: x < y for: 5 < 110
-Generators.tests.cpp:<line number>: passed: x < y for: 6 < 101
-Generators.tests.cpp:<line number>: passed: x < y for: 6 < 102
-Generators.tests.cpp:<line number>: passed: x < y for: 6 < 103
-Generators.tests.cpp:<line number>: passed: x < y for: 6 < 104
-Generators.tests.cpp:<line number>: passed: x < y for: 6 < 105
-Generators.tests.cpp:<line number>: passed: x < y for: 6 < 106
-Generators.tests.cpp:<line number>: passed: x < y for: 6 < 107
-Generators.tests.cpp:<line number>: passed: x < y for: 6 < 108
-Generators.tests.cpp:<line number>: passed: x < y for: 6 < 109
-Generators.tests.cpp:<line number>: passed: x < y for: 6 < 110
-Generators.tests.cpp:<line number>: passed: x < y for: 7 < 101
-Generators.tests.cpp:<line number>: passed: x < y for: 7 < 102
-Generators.tests.cpp:<line number>: passed: x < y for: 7 < 103
-Generators.tests.cpp:<line number>: passed: x < y for: 7 < 104
-Generators.tests.cpp:<line number>: passed: x < y for: 7 < 105
-Generators.tests.cpp:<line number>: passed: x < y for: 7 < 106
-Generators.tests.cpp:<line number>: passed: x < y for: 7 < 107
-Generators.tests.cpp:<line number>: passed: x < y for: 7 < 108
-Generators.tests.cpp:<line number>: passed: x < y for: 7 < 109
-Generators.tests.cpp:<line number>: passed: x < y for: 7 < 110
-Generators.tests.cpp:<line number>: passed: x < y for: 8 < 101
-Generators.tests.cpp:<line number>: passed: x < y for: 8 < 102
-Generators.tests.cpp:<line number>: passed: x < y for: 8 < 103
-Generators.tests.cpp:<line number>: passed: x < y for: 8 < 104
-Generators.tests.cpp:<line number>: passed: x < y for: 8 < 105
-Generators.tests.cpp:<line number>: passed: x < y for: 8 < 106
-Generators.tests.cpp:<line number>: passed: x < y for: 8 < 107
-Generators.tests.cpp:<line number>: passed: x < y for: 8 < 108
-Generators.tests.cpp:<line number>: passed: x < y for: 8 < 109
-Generators.tests.cpp:<line number>: passed: x < y for: 8 < 110
-Generators.tests.cpp:<line number>: passed: x < y for: 9 < 101
-Generators.tests.cpp:<line number>: passed: x < y for: 9 < 102
-Generators.tests.cpp:<line number>: passed: x < y for: 9 < 103
-Generators.tests.cpp:<line number>: passed: x < y for: 9 < 104
-Generators.tests.cpp:<line number>: passed: x < y for: 9 < 105
-Generators.tests.cpp:<line number>: passed: x < y for: 9 < 106
-Generators.tests.cpp:<line number>: passed: x < y for: 9 < 107
-Generators.tests.cpp:<line number>: passed: x < y for: 9 < 108
-Generators.tests.cpp:<line number>: passed: x < y for: 9 < 109
-Generators.tests.cpp:<line number>: passed: x < y for: 9 < 110
-Generators.tests.cpp:<line number>: passed: x < y for: 10 < 101
-Generators.tests.cpp:<line number>: passed: x < y for: 10 < 102
-Generators.tests.cpp:<line number>: passed: x < y for: 10 < 103
-Generators.tests.cpp:<line number>: passed: x < y for: 10 < 104
-Generators.tests.cpp:<line number>: passed: x < y for: 10 < 105
-Generators.tests.cpp:<line number>: passed: x < y for: 10 < 106
-Generators.tests.cpp:<line number>: passed: x < y for: 10 < 107
-Generators.tests.cpp:<line number>: passed: x < y for: 10 < 108
-Generators.tests.cpp:<line number>: passed: x < y for: 10 < 109
-Generators.tests.cpp:<line number>: passed: x < y for: 10 < 110
+Generators.tests.cpp:<line number>: passed: x < y for: 1 < 4
+Generators.tests.cpp:<line number>: passed: y < z for: 4 < 7
+Generators.tests.cpp:<line number>: passed: x < z for: 1 < 7
+Generators.tests.cpp:<line number>: passed: x < y for: 1 < 4
+Generators.tests.cpp:<line number>: passed: y < z for: 4 < 8
+Generators.tests.cpp:<line number>: passed: x < z for: 1 < 8
+Generators.tests.cpp:<line number>: passed: x < y for: 1 < 4
+Generators.tests.cpp:<line number>: passed: y < z for: 4 < 9
+Generators.tests.cpp:<line number>: passed: x < z for: 1 < 9
+Generators.tests.cpp:<line number>: passed: x < y for: 1 < 5
+Generators.tests.cpp:<line number>: passed: y < z for: 5 < 7
+Generators.tests.cpp:<line number>: passed: x < z for: 1 < 7
+Generators.tests.cpp:<line number>: passed: x < y for: 1 < 5
+Generators.tests.cpp:<line number>: passed: y < z for: 5 < 8
+Generators.tests.cpp:<line number>: passed: x < z for: 1 < 8
+Generators.tests.cpp:<line number>: passed: x < y for: 1 < 5
+Generators.tests.cpp:<line number>: passed: y < z for: 5 < 9
+Generators.tests.cpp:<line number>: passed: x < z for: 1 < 9
+Generators.tests.cpp:<line number>: passed: x < y for: 1 < 6
+Generators.tests.cpp:<line number>: passed: y < z for: 6 < 7
+Generators.tests.cpp:<line number>: passed: x < z for: 1 < 7
+Generators.tests.cpp:<line number>: passed: x < y for: 1 < 6
+Generators.tests.cpp:<line number>: passed: y < z for: 6 < 8
+Generators.tests.cpp:<line number>: passed: x < z for: 1 < 8
+Generators.tests.cpp:<line number>: passed: x < y for: 1 < 6
+Generators.tests.cpp:<line number>: passed: y < z for: 6 < 9
+Generators.tests.cpp:<line number>: passed: x < z for: 1 < 9
+Generators.tests.cpp:<line number>: passed: x < y for: 2 < 4
+Generators.tests.cpp:<line number>: passed: y < z for: 4 < 7
+Generators.tests.cpp:<line number>: passed: x < z for: 2 < 7
+Generators.tests.cpp:<line number>: passed: x < y for: 2 < 4
+Generators.tests.cpp:<line number>: passed: y < z for: 4 < 8
+Generators.tests.cpp:<line number>: passed: x < z for: 2 < 8
+Generators.tests.cpp:<line number>: passed: x < y for: 2 < 4
+Generators.tests.cpp:<line number>: passed: y < z for: 4 < 9
+Generators.tests.cpp:<line number>: passed: x < z for: 2 < 9
+Generators.tests.cpp:<line number>: passed: x < y for: 2 < 5
+Generators.tests.cpp:<line number>: passed: y < z for: 5 < 7
+Generators.tests.cpp:<line number>: passed: x < z for: 2 < 7
+Generators.tests.cpp:<line number>: passed: x < y for: 2 < 5
+Generators.tests.cpp:<line number>: passed: y < z for: 5 < 8
+Generators.tests.cpp:<line number>: passed: x < z for: 2 < 8
+Generators.tests.cpp:<line number>: passed: x < y for: 2 < 5
+Generators.tests.cpp:<line number>: passed: y < z for: 5 < 9
+Generators.tests.cpp:<line number>: passed: x < z for: 2 < 9
+Generators.tests.cpp:<line number>: passed: x < y for: 2 < 6
+Generators.tests.cpp:<line number>: passed: y < z for: 6 < 7
+Generators.tests.cpp:<line number>: passed: x < z for: 2 < 7
+Generators.tests.cpp:<line number>: passed: x < y for: 2 < 6
+Generators.tests.cpp:<line number>: passed: y < z for: 6 < 8
+Generators.tests.cpp:<line number>: passed: x < z for: 2 < 8
+Generators.tests.cpp:<line number>: passed: x < y for: 2 < 6
+Generators.tests.cpp:<line number>: passed: y < z for: 6 < 9
+Generators.tests.cpp:<line number>: passed: x < z for: 2 < 9
+Generators.tests.cpp:<line number>: passed: x < y for: 3 < 4
+Generators.tests.cpp:<line number>: passed: y < z for: 4 < 7
+Generators.tests.cpp:<line number>: passed: x < z for: 3 < 7
+Generators.tests.cpp:<line number>: passed: x < y for: 3 < 4
+Generators.tests.cpp:<line number>: passed: y < z for: 4 < 8
+Generators.tests.cpp:<line number>: passed: x < z for: 3 < 8
+Generators.tests.cpp:<line number>: passed: x < y for: 3 < 4
+Generators.tests.cpp:<line number>: passed: y < z for: 4 < 9
+Generators.tests.cpp:<line number>: passed: x < z for: 3 < 9
+Generators.tests.cpp:<line number>: passed: x < y for: 3 < 5
+Generators.tests.cpp:<line number>: passed: y < z for: 5 < 7
+Generators.tests.cpp:<line number>: passed: x < z for: 3 < 7
+Generators.tests.cpp:<line number>: passed: x < y for: 3 < 5
+Generators.tests.cpp:<line number>: passed: y < z for: 5 < 8
+Generators.tests.cpp:<line number>: passed: x < z for: 3 < 8
+Generators.tests.cpp:<line number>: passed: x < y for: 3 < 5
+Generators.tests.cpp:<line number>: passed: y < z for: 5 < 9
+Generators.tests.cpp:<line number>: passed: x < z for: 3 < 9
+Generators.tests.cpp:<line number>: passed: x < y for: 3 < 6
+Generators.tests.cpp:<line number>: passed: y < z for: 6 < 7
+Generators.tests.cpp:<line number>: passed: x < z for: 3 < 7
+Generators.tests.cpp:<line number>: passed: x < y for: 3 < 6
+Generators.tests.cpp:<line number>: passed: y < z for: 6 < 8
+Generators.tests.cpp:<line number>: passed: x < z for: 3 < 8
+Generators.tests.cpp:<line number>: passed: x < y for: 3 < 6
+Generators.tests.cpp:<line number>: passed: y < z for: 6 < 9
+Generators.tests.cpp:<line number>: passed: x < z for: 3 < 9
 Class.tests.cpp:<line number>: failed: s == "world" for: "hello" == "world"
 Class.tests.cpp:<line number>: passed: s == "hello" for: "hello" == "hello"
 Class.tests.cpp:<line number>: failed: Template_Fixture_2<TestType>::m_a.size() == 1 for: 0 == 1
@@ -418,48 +399,98 @@ Matchers.tests.cpp:<line number>: passed: WithinAbs(1.f, 0.f)
 Matchers.tests.cpp:<line number>: passed: WithinAbs(1.f, -1.f), std::domain_error
 Matchers.tests.cpp:<line number>: passed: WithinULP(1.f, 0)
 Matchers.tests.cpp:<line number>: passed: WithinULP(1.f, -1), std::domain_error
-Generators.tests.cpp:<line number>: passed: with 2 messages: 'i := "a"' and 'j := 8'
-Generators.tests.cpp:<line number>: passed: with 2 messages: 'i := "a"' and 'j := 9'
-Generators.tests.cpp:<line number>: passed: with 2 messages: 'i := "a"' and 'j := 10'
-Generators.tests.cpp:<line number>: passed: with 2 messages: 'i := "a"' and 'j := 2'
-Generators.tests.cpp:<line number>: passed: with 2 messages: 'i := "a"' and 'j := 3.141'
-Generators.tests.cpp:<line number>: passed: with 2 messages: 'i := "a"' and 'j := 1.379'
-Generators.tests.cpp:<line number>: passed: with 2 messages: 'i := "b"' and 'j := 8'
-Generators.tests.cpp:<line number>: passed: with 2 messages: 'i := "b"' and 'j := 9'
-Generators.tests.cpp:<line number>: passed: with 2 messages: 'i := "b"' and 'j := 10'
-Generators.tests.cpp:<line number>: passed: with 2 messages: 'i := "b"' and 'j := 2'
-Generators.tests.cpp:<line number>: passed: with 2 messages: 'i := "b"' and 'j := 3.141'
-Generators.tests.cpp:<line number>: passed: with 2 messages: 'i := "b"' and 'j := 1.379'
-Generators.tests.cpp:<line number>: passed: with 2 messages: 'i := "c"' and 'j := 8'
-Generators.tests.cpp:<line number>: passed: with 2 messages: 'i := "c"' and 'j := 9'
-Generators.tests.cpp:<line number>: passed: with 2 messages: 'i := "c"' and 'j := 10'
-Generators.tests.cpp:<line number>: passed: with 2 messages: 'i := "c"' and 'j := 2'
-Generators.tests.cpp:<line number>: passed: with 2 messages: 'i := "c"' and 'j := 3.141'
-Generators.tests.cpp:<line number>: passed: with 2 messages: 'i := "c"' and 'j := 1.379'
-GeneratorsImpl.tests.cpp:<line number>: passed: gen.size() == 2 for: 2 == 2
-GeneratorsImpl.tests.cpp:<line number>: passed: gen[0] == 1 for: 1 == 1
-GeneratorsImpl.tests.cpp:<line number>: passed: gen[1] == 2 for: 2 == 2
-GeneratorsImpl.tests.cpp:<line number>: passed: gen.size() == 4 for: 4 == 4
-GeneratorsImpl.tests.cpp:<line number>: passed: gen[0] == 3 for: 3 == 3
-GeneratorsImpl.tests.cpp:<line number>: passed: gen[1] == 1 for: 1 == 1
-GeneratorsImpl.tests.cpp:<line number>: passed: gen[2] == 4 for: 4 == 4
-GeneratorsImpl.tests.cpp:<line number>: passed: gen[3] == 1 for: 1 == 1
-GeneratorsImpl.tests.cpp:<line number>: passed: gen.size() == 4 for: 4 == 4
-GeneratorsImpl.tests.cpp:<line number>: passed: gen[0] == 1 for: 1 == 1
-GeneratorsImpl.tests.cpp:<line number>: passed: gen[1] == 2 for: 2 == 2
-GeneratorsImpl.tests.cpp:<line number>: passed: gen[2] == 9 for: 9 == 9
-GeneratorsImpl.tests.cpp:<line number>: passed: gen[3] == 7 for: 7 == 7
-GeneratorsImpl.tests.cpp:<line number>: passed: gen.size() == 2 for: 2 == 2
-GeneratorsImpl.tests.cpp:<line number>: passed: gen[0] == 3 for: 3 == 3
-GeneratorsImpl.tests.cpp:<line number>: passed: gen[1] == 1 for: 1 == 1
-GeneratorsImpl.tests.cpp:<line number>: passed: gen.size() == 2 for: 2 == 2
-GeneratorsImpl.tests.cpp:<line number>: passed: gen[0] == 3 for: 3 == 3
-GeneratorsImpl.tests.cpp:<line number>: passed: gen[1] == 1 for: 1 == 1
-GeneratorsImpl.tests.cpp:<line number>: passed: base->size() == 4 for: 4 == 4
-GeneratorsImpl.tests.cpp:<line number>: passed: typed for: 0x<hex digits>
-GeneratorsImpl.tests.cpp:<line number>: passed: typed->size() == 4 for: 4 == 4
-GeneratorsImpl.tests.cpp:<line number>: passed: (*typed)[0] == 7 for: 7 == 7
-GeneratorsImpl.tests.cpp:<line number>: passed: (*typed)[3] == 11 for: 11 == 11
+Generators.tests.cpp:<line number>: passed: i % 2 == 0 for: 0 == 0
+Generators.tests.cpp:<line number>: passed: i % 2 == 0 for: 0 == 0
+Generators.tests.cpp:<line number>: passed: i % 2 == 0 for: 0 == 0
+Generators.tests.cpp:<line number>: passed: i < 4 for: 1 < 4
+Generators.tests.cpp:<line number>: passed: i < 4 for: 2 < 4
+Generators.tests.cpp:<line number>: passed: i < 4 for: 3 < 4
+Generators.tests.cpp:<line number>: passed: i % 2 == 0 for: 0 == 0
+Generators.tests.cpp:<line number>: passed: i % 2 == 0 for: 0 == 0
+Generators.tests.cpp:<line number>: passed: i % 2 == 0 for: 0 == 0
+Generators.tests.cpp:<line number>: passed: i.size() == 1 for: 1 == 1
+Generators.tests.cpp:<line number>: passed: i.size() == 1 for: 1 == 1
+Generators.tests.cpp:<line number>: passed: i.size() == 1 for: 1 == 1
+Generators.tests.cpp:<line number>: passed: j > 0 for: 1 > 0
+Generators.tests.cpp:<line number>: passed: j > 0 for: 2 > 0
+Generators.tests.cpp:<line number>: passed: j > 0 for: 3 > 0
+Generators.tests.cpp:<line number>: passed: j > 0 for: 1 > 0
+Generators.tests.cpp:<line number>: passed: j > 0 for: 2 > 0
+Generators.tests.cpp:<line number>: passed: j > 0 for: 3 > 0
+Generators.tests.cpp:<line number>: passed: j < i for: -3 < 1
+Generators.tests.cpp:<line number>: passed: j < i for: -2 < 1
+Generators.tests.cpp:<line number>: passed: j < i for: -1 < 1
+Generators.tests.cpp:<line number>: passed: 4u * i > str.size() for: 4 > 1
+Generators.tests.cpp:<line number>: passed: 4u * i > str.size() for: 4 > 2
+Generators.tests.cpp:<line number>: passed: 4u * i > str.size() for: 4 > 3
+Generators.tests.cpp:<line number>: passed: j < i for: -3 < 2
+Generators.tests.cpp:<line number>: passed: j < i for: -2 < 2
+Generators.tests.cpp:<line number>: passed: j < i for: -1 < 2
+Generators.tests.cpp:<line number>: passed: 4u * i > str.size() for: 8 > 1
+Generators.tests.cpp:<line number>: passed: 4u * i > str.size() for: 8 > 2
+Generators.tests.cpp:<line number>: passed: 4u * i > str.size() for: 8 > 3
+Generators.tests.cpp:<line number>: passed: j < i for: -3 < 3
+Generators.tests.cpp:<line number>: passed: j < i for: -2 < 3
+Generators.tests.cpp:<line number>: passed: j < i for: -1 < 3
+Generators.tests.cpp:<line number>: passed: 4u * i > str.size() for: 12 > 1
+Generators.tests.cpp:<line number>: passed: 4u * i > str.size() for: 12 > 2
+Generators.tests.cpp:<line number>: passed: 4u * i > str.size() for: 12 > 3
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.get() == 123 for: 123 == 123
+GeneratorsImpl.tests.cpp:<line number>: passed: !(gen.next()) for: !false
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.get() == 1 for: 1 == 1
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.next() for: true
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.get() == 3 for: 3 == 3
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.next() for: true
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.get() == 5 for: 5 == 5
+GeneratorsImpl.tests.cpp:<line number>: passed: !(gen.next()) for: !false
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.get() == 1 for: 1 == 1
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.next() for: true
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.get() == 5 for: 5 == 5
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.next() for: true
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.get() == 2 for: 2 == 2
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.next() for: true
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.get() == 4 for: 4 == 4
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.next() for: true
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.get() == 0 for: 0 == 0
+GeneratorsImpl.tests.cpp:<line number>: passed: !(gen.next()) for: !false
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.get().size() == 2 for: 2 == 2
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.get() == "aa" for: "aa" == "aa"
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.next() for: true
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.get() == "bb" for: "bb" == "bb"
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.next() for: true
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.get() == "cc" for: "cc" == "cc"
+GeneratorsImpl.tests.cpp:<line number>: passed: !(gen.next()) for: !false
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.get() == 1 for: 1 == 1
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.next() for: true
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.get() == 3 for: 3 == 3
+GeneratorsImpl.tests.cpp:<line number>: passed: !(gen.next()) for: !false
+GeneratorsImpl.tests.cpp:<line number>: passed: filter([] (int) { return false; }, value(1)), Catch::GeneratorException
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.get() == 1 for: 1 == 1
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.next() for: true
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.get() == 2 for: 2 == 2
+GeneratorsImpl.tests.cpp:<line number>: passed: !(gen.next()) for: !false
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.get() == 1 for: 1 == 1
+GeneratorsImpl.tests.cpp:<line number>: passed: !(gen.next()) for: !false
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.get() == 2.0 for: 2.0 == 2.0
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.next() for: true
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.get() == 4.0 for: 4.0 == 4.0
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.next() for: true
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.get() == 6.0 for: 6.0 == 6.0
+GeneratorsImpl.tests.cpp:<line number>: passed: !(gen.next()) for: !false
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.get() == 3 for: 3 == 3
+GeneratorsImpl.tests.cpp:<line number>: passed: !(gen.next()) for: !false
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.get() == 1 for: 1 == 1
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.next() for: true
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.get() == 2 for: 2 == 2
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.next() for: true
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.get() == 3 for: 3 == 3
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.next() for: true
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.get() == 1 for: 1 == 1
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.next() for: true
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.get() == 2 for: 2 == 2
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.next() for: true
+GeneratorsImpl.tests.cpp:<line number>: passed: gen.get() == 3 for: 3 == 3
+GeneratorsImpl.tests.cpp:<line number>: passed: !(gen.next()) for: !false
 Approx.tests.cpp:<line number>: passed: d >= Approx( 1.22 ) for: 1.23 >= Approx( 1.22 )
 Approx.tests.cpp:<line number>: passed: d >= Approx( 1.23 ) for: 1.23 >= Approx( 1.23 )
 Approx.tests.cpp:<line number>: passed: !(d >= Approx( 1.24 )) for: !(1.23 >= Approx( 1.24 ))
@@ -1274,6 +1305,10 @@ Generators.tests.cpp:<line number>: passed: data.str.size() == data.len for: 3 =
 Generators.tests.cpp:<line number>: passed: data.str.size() == data.len for: 3 == 3
 Generators.tests.cpp:<line number>: passed: data.str.size() == data.len for: 5 == 5
 Generators.tests.cpp:<line number>: passed: data.str.size() == data.len for: 4 == 4
+Generators.tests.cpp:<line number>: passed: strlen(std::get<0>(data)) == static_cast<size_t>(std::get<1>(data)) for: 5 == 5
+Generators.tests.cpp:<line number>: passed: strlen(std::get<0>(data)) == static_cast<size_t>(std::get<1>(data)) for: 6 == 6
+Generators.tests.cpp:<line number>: passed: strlen(std::get<0>(data)) == static_cast<size_t>(std::get<1>(data)) for: 5 == 5
+Generators.tests.cpp:<line number>: passed: strlen(std::get<0>(data)) == static_cast<size_t>(std::get<1>(data)) for: 6 == 6
 Exception.tests.cpp:<line number>: failed: unexpected exception with message: 'Why would you throw a std::string?'
 Misc.tests.cpp:<line number>: passed: result == "\"wide load\"" for: ""wide load"" == ""wide load""
 Misc.tests.cpp:<line number>: passed: result == "\"wide load\"" for: ""wide load"" == ""wide load""
diff --git a/projects/SelfTest/Baselines/console.std.approved.txt b/projects/SelfTest/Baselines/console.std.approved.txt
index dff912cf6e..a9ca0277d5 100644
--- a/projects/SelfTest/Baselines/console.std.approved.txt
+++ b/projects/SelfTest/Baselines/console.std.approved.txt
@@ -1170,6 +1170,6 @@ due to unexpected exception with message:
   Why would you throw a std::string?
 
 ===============================================================================
-test cases:  243 |  183 passed |  56 failed |  4 failed as expected
-assertions: 1262 | 1126 passed | 115 failed | 21 failed as expected
+test cases:  245 |  185 passed |  56 failed |  4 failed as expected
+assertions: 1297 | 1161 passed | 115 failed | 21 failed as expected
 
diff --git a/projects/SelfTest/Baselines/console.sw.approved.txt b/projects/SelfTest/Baselines/console.sw.approved.txt
index 79334630c1..92a78c57d2 100644
--- a/projects/SelfTest/Baselines/console.sw.approved.txt
+++ b/projects/SelfTest/Baselines/console.sw.approved.txt
@@ -456,7 +456,7 @@ with expansion:
   !false
 
 -------------------------------------------------------------------------------
-10x10 ints
+3x3x3 ints
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
@@ -464,98 +464,20 @@ Generators.tests.cpp:<line number>
 Generators.tests.cpp:<line number>: PASSED:
   CHECK( x < y )
 with expansion:
-  1 < 101
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
-
-Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
-with expansion:
-  1 < 102
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
-
-Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
-with expansion:
-  1 < 103
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
-
-Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
-with expansion:
-  1 < 104
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
-
-Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
-with expansion:
-  1 < 105
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
-
-Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
-with expansion:
-  1 < 106
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
-
-Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
-with expansion:
-  1 < 107
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
+  1 < 4
 
 Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
+  CHECK( y < z )
 with expansion:
-  1 < 108
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
+  4 < 7
 
 Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
+  REQUIRE( x < z )
 with expansion:
-  1 < 109
+  1 < 7
 
 -------------------------------------------------------------------------------
-10x10 ints
+3x3x3 ints
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
@@ -563,32 +485,20 @@ Generators.tests.cpp:<line number>
 Generators.tests.cpp:<line number>: PASSED:
   CHECK( x < y )
 with expansion:
-  1 < 110
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
+  1 < 4
 
 Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
+  CHECK( y < z )
 with expansion:
-  2 < 101
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
+  4 < 8
 
 Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
+  REQUIRE( x < z )
 with expansion:
-  2 < 102
+  1 < 8
 
 -------------------------------------------------------------------------------
-10x10 ints
+3x3x3 ints
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
@@ -596,65 +506,20 @@ Generators.tests.cpp:<line number>
 Generators.tests.cpp:<line number>: PASSED:
   CHECK( x < y )
 with expansion:
-  2 < 103
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
+  1 < 4
 
 Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
+  CHECK( y < z )
 with expansion:
-  2 < 104
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
-
-Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
-with expansion:
-  2 < 105
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
-
-Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
-with expansion:
-  2 < 106
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
-
-Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
-with expansion:
-  2 < 107
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
+  4 < 9
 
 Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
+  REQUIRE( x < z )
 with expansion:
-  2 < 108
+  1 < 9
 
 -------------------------------------------------------------------------------
-10x10 ints
+3x3x3 ints
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
@@ -662,32 +527,20 @@ Generators.tests.cpp:<line number>
 Generators.tests.cpp:<line number>: PASSED:
   CHECK( x < y )
 with expansion:
-  2 < 109
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
+  1 < 5
 
 Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
+  CHECK( y < z )
 with expansion:
-  2 < 110
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
+  5 < 7
 
 Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
+  REQUIRE( x < z )
 with expansion:
-  3 < 101
+  1 < 7
 
 -------------------------------------------------------------------------------
-10x10 ints
+3x3x3 ints
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
@@ -695,32 +548,20 @@ Generators.tests.cpp:<line number>
 Generators.tests.cpp:<line number>: PASSED:
   CHECK( x < y )
 with expansion:
-  3 < 102
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
+  1 < 5
 
 Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
+  CHECK( y < z )
 with expansion:
-  3 < 103
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
+  5 < 8
 
 Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
+  REQUIRE( x < z )
 with expansion:
-  3 < 104
+  1 < 8
 
 -------------------------------------------------------------------------------
-10x10 ints
+3x3x3 ints
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
@@ -728,32 +569,20 @@ Generators.tests.cpp:<line number>
 Generators.tests.cpp:<line number>: PASSED:
   CHECK( x < y )
 with expansion:
-  3 < 105
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
+  1 < 5
 
 Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
+  CHECK( y < z )
 with expansion:
-  3 < 106
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
+  5 < 9
 
 Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
+  REQUIRE( x < z )
 with expansion:
-  3 < 107
+  1 < 9
 
 -------------------------------------------------------------------------------
-10x10 ints
+3x3x3 ints
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
@@ -761,32 +590,20 @@ Generators.tests.cpp:<line number>
 Generators.tests.cpp:<line number>: PASSED:
   CHECK( x < y )
 with expansion:
-  3 < 108
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
+  1 < 6
 
 Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
+  CHECK( y < z )
 with expansion:
-  3 < 109
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
+  6 < 7
 
 Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
+  REQUIRE( x < z )
 with expansion:
-  3 < 110
+  1 < 7
 
 -------------------------------------------------------------------------------
-10x10 ints
+3x3x3 ints
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
@@ -794,32 +611,20 @@ Generators.tests.cpp:<line number>
 Generators.tests.cpp:<line number>: PASSED:
   CHECK( x < y )
 with expansion:
-  4 < 101
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
+  1 < 6
 
 Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
+  CHECK( y < z )
 with expansion:
-  4 < 102
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
+  6 < 8
 
 Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
+  REQUIRE( x < z )
 with expansion:
-  4 < 103
+  1 < 8
 
 -------------------------------------------------------------------------------
-10x10 ints
+3x3x3 ints
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
@@ -827,32 +632,20 @@ Generators.tests.cpp:<line number>
 Generators.tests.cpp:<line number>: PASSED:
   CHECK( x < y )
 with expansion:
-  4 < 104
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
+  1 < 6
 
 Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
+  CHECK( y < z )
 with expansion:
-  4 < 105
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
+  6 < 9
 
 Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
+  REQUIRE( x < z )
 with expansion:
-  4 < 106
+  1 < 9
 
 -------------------------------------------------------------------------------
-10x10 ints
+3x3x3 ints
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
@@ -860,32 +653,20 @@ Generators.tests.cpp:<line number>
 Generators.tests.cpp:<line number>: PASSED:
   CHECK( x < y )
 with expansion:
-  4 < 107
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
+  2 < 4
 
 Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
+  CHECK( y < z )
 with expansion:
-  4 < 108
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
+  4 < 7
 
 Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
+  REQUIRE( x < z )
 with expansion:
-  4 < 109
+  2 < 7
 
 -------------------------------------------------------------------------------
-10x10 ints
+3x3x3 ints
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
@@ -893,32 +674,20 @@ Generators.tests.cpp:<line number>
 Generators.tests.cpp:<line number>: PASSED:
   CHECK( x < y )
 with expansion:
-  4 < 110
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
+  2 < 4
 
 Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
+  CHECK( y < z )
 with expansion:
-  5 < 101
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
+  4 < 8
 
 Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
+  REQUIRE( x < z )
 with expansion:
-  5 < 102
+  2 < 8
 
 -------------------------------------------------------------------------------
-10x10 ints
+3x3x3 ints
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
@@ -926,32 +695,20 @@ Generators.tests.cpp:<line number>
 Generators.tests.cpp:<line number>: PASSED:
   CHECK( x < y )
 with expansion:
-  5 < 103
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
+  2 < 4
 
 Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
+  CHECK( y < z )
 with expansion:
-  5 < 104
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
+  4 < 9
 
 Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
+  REQUIRE( x < z )
 with expansion:
-  5 < 105
+  2 < 9
 
 -------------------------------------------------------------------------------
-10x10 ints
+3x3x3 ints
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
@@ -959,296 +716,20 @@ Generators.tests.cpp:<line number>
 Generators.tests.cpp:<line number>: PASSED:
   CHECK( x < y )
 with expansion:
-  5 < 106
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
-
-Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
-with expansion:
-  5 < 107
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
-
-Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
-with expansion:
-  5 < 108
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
-
-Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
-with expansion:
-  5 < 109
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
-
-Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
-with expansion:
-  5 < 110
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
-
-Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
-with expansion:
-  6 < 101
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
-
-Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
-with expansion:
-  6 < 102
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
-
-Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
-with expansion:
-  6 < 103
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
-
-Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
-with expansion:
-  6 < 104
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
-
-Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
-with expansion:
-  6 < 105
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
-
-Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
-with expansion:
-  6 < 106
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
-
-Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
-with expansion:
-  6 < 107
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
-
-Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
-with expansion:
-  6 < 108
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
-
-Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
-with expansion:
-  6 < 109
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
-
-Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
-with expansion:
-  6 < 110
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
-
-Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
-with expansion:
-  7 < 101
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
-
-Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
-with expansion:
-  7 < 102
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
-
-Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
-with expansion:
-  7 < 103
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
-
-Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
-with expansion:
-  7 < 104
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
-
-Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
-with expansion:
-  7 < 105
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
-
-Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
-with expansion:
-  7 < 106
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
-
-Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
-with expansion:
-  7 < 107
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
-
-Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
-with expansion:
-  7 < 108
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
-
-Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
-with expansion:
-  7 < 109
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
-
-Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
-with expansion:
-  7 < 110
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
-
-Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
-with expansion:
-  8 < 101
-
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
+  2 < 5
 
 Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
+  CHECK( y < z )
+with expansion:
+  5 < 7
+
+Generators.tests.cpp:<line number>: PASSED:
+  REQUIRE( x < z )
 with expansion:
-  8 < 102
+  2 < 7
 
 -------------------------------------------------------------------------------
-10x10 ints
+3x3x3 ints
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
@@ -1256,21 +737,20 @@ Generators.tests.cpp:<line number>
 Generators.tests.cpp:<line number>: PASSED:
   CHECK( x < y )
 with expansion:
-  8 < 103
+  2 < 5
 
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
+Generators.tests.cpp:<line number>: PASSED:
+  CHECK( y < z )
+with expansion:
+  5 < 8
 
 Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
+  REQUIRE( x < z )
 with expansion:
-  8 < 104
+  2 < 8
 
 -------------------------------------------------------------------------------
-10x10 ints
+3x3x3 ints
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
@@ -1278,21 +758,20 @@ Generators.tests.cpp:<line number>
 Generators.tests.cpp:<line number>: PASSED:
   CHECK( x < y )
 with expansion:
-  8 < 105
+  2 < 5
 
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
+Generators.tests.cpp:<line number>: PASSED:
+  CHECK( y < z )
+with expansion:
+  5 < 9
 
 Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
+  REQUIRE( x < z )
 with expansion:
-  8 < 106
+  2 < 9
 
 -------------------------------------------------------------------------------
-10x10 ints
+3x3x3 ints
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
@@ -1300,21 +779,20 @@ Generators.tests.cpp:<line number>
 Generators.tests.cpp:<line number>: PASSED:
   CHECK( x < y )
 with expansion:
-  8 < 107
+  2 < 6
 
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
+Generators.tests.cpp:<line number>: PASSED:
+  CHECK( y < z )
+with expansion:
+  6 < 7
 
 Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
+  REQUIRE( x < z )
 with expansion:
-  8 < 108
+  2 < 7
 
 -------------------------------------------------------------------------------
-10x10 ints
+3x3x3 ints
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
@@ -1322,21 +800,20 @@ Generators.tests.cpp:<line number>
 Generators.tests.cpp:<line number>: PASSED:
   CHECK( x < y )
 with expansion:
-  8 < 109
+  2 < 6
 
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
+Generators.tests.cpp:<line number>: PASSED:
+  CHECK( y < z )
+with expansion:
+  6 < 8
 
 Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
+  REQUIRE( x < z )
 with expansion:
-  8 < 110
+  2 < 8
 
 -------------------------------------------------------------------------------
-10x10 ints
+3x3x3 ints
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
@@ -1344,21 +821,20 @@ Generators.tests.cpp:<line number>
 Generators.tests.cpp:<line number>: PASSED:
   CHECK( x < y )
 with expansion:
-  9 < 101
+  2 < 6
 
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
+Generators.tests.cpp:<line number>: PASSED:
+  CHECK( y < z )
+with expansion:
+  6 < 9
 
 Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
+  REQUIRE( x < z )
 with expansion:
-  9 < 102
+  2 < 9
 
 -------------------------------------------------------------------------------
-10x10 ints
+3x3x3 ints
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
@@ -1366,21 +842,20 @@ Generators.tests.cpp:<line number>
 Generators.tests.cpp:<line number>: PASSED:
   CHECK( x < y )
 with expansion:
-  9 < 103
+  3 < 4
 
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
+Generators.tests.cpp:<line number>: PASSED:
+  CHECK( y < z )
+with expansion:
+  4 < 7
 
 Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
+  REQUIRE( x < z )
 with expansion:
-  9 < 104
+  3 < 7
 
 -------------------------------------------------------------------------------
-10x10 ints
+3x3x3 ints
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
@@ -1388,21 +863,20 @@ Generators.tests.cpp:<line number>
 Generators.tests.cpp:<line number>: PASSED:
   CHECK( x < y )
 with expansion:
-  9 < 105
+  3 < 4
 
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
+Generators.tests.cpp:<line number>: PASSED:
+  CHECK( y < z )
+with expansion:
+  4 < 8
 
 Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
+  REQUIRE( x < z )
 with expansion:
-  9 < 106
+  3 < 8
 
 -------------------------------------------------------------------------------
-10x10 ints
+3x3x3 ints
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
@@ -1410,21 +884,20 @@ Generators.tests.cpp:<line number>
 Generators.tests.cpp:<line number>: PASSED:
   CHECK( x < y )
 with expansion:
-  9 < 107
+  3 < 4
 
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
+Generators.tests.cpp:<line number>: PASSED:
+  CHECK( y < z )
+with expansion:
+  4 < 9
 
 Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
+  REQUIRE( x < z )
 with expansion:
-  9 < 108
+  3 < 9
 
 -------------------------------------------------------------------------------
-10x10 ints
+3x3x3 ints
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
@@ -1432,21 +905,20 @@ Generators.tests.cpp:<line number>
 Generators.tests.cpp:<line number>: PASSED:
   CHECK( x < y )
 with expansion:
-  9 < 109
+  3 < 5
 
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
+Generators.tests.cpp:<line number>: PASSED:
+  CHECK( y < z )
+with expansion:
+  5 < 7
 
 Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
+  REQUIRE( x < z )
 with expansion:
-  9 < 110
+  3 < 7
 
 -------------------------------------------------------------------------------
-10x10 ints
+3x3x3 ints
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
@@ -1454,21 +926,20 @@ Generators.tests.cpp:<line number>
 Generators.tests.cpp:<line number>: PASSED:
   CHECK( x < y )
 with expansion:
-  10 < 101
+  3 < 5
 
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
+Generators.tests.cpp:<line number>: PASSED:
+  CHECK( y < z )
+with expansion:
+  5 < 8
 
 Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
+  REQUIRE( x < z )
 with expansion:
-  10 < 102
+  3 < 8
 
 -------------------------------------------------------------------------------
-10x10 ints
+3x3x3 ints
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
@@ -1476,21 +947,20 @@ Generators.tests.cpp:<line number>
 Generators.tests.cpp:<line number>: PASSED:
   CHECK( x < y )
 with expansion:
-  10 < 103
+  3 < 5
 
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
+Generators.tests.cpp:<line number>: PASSED:
+  CHECK( y < z )
+with expansion:
+  5 < 9
 
 Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
+  REQUIRE( x < z )
 with expansion:
-  10 < 104
+  3 < 9
 
 -------------------------------------------------------------------------------
-10x10 ints
+3x3x3 ints
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
@@ -1498,21 +968,20 @@ Generators.tests.cpp:<line number>
 Generators.tests.cpp:<line number>: PASSED:
   CHECK( x < y )
 with expansion:
-  10 < 105
+  3 < 6
 
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
+Generators.tests.cpp:<line number>: PASSED:
+  CHECK( y < z )
+with expansion:
+  6 < 7
 
 Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
+  REQUIRE( x < z )
 with expansion:
-  10 < 106
+  3 < 7
 
 -------------------------------------------------------------------------------
-10x10 ints
+3x3x3 ints
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
@@ -1520,21 +989,20 @@ Generators.tests.cpp:<line number>
 Generators.tests.cpp:<line number>: PASSED:
   CHECK( x < y )
 with expansion:
-  10 < 107
+  3 < 6
 
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
+Generators.tests.cpp:<line number>: PASSED:
+  CHECK( y < z )
+with expansion:
+  6 < 8
 
 Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
+  REQUIRE( x < z )
 with expansion:
-  10 < 108
+  3 < 8
 
 -------------------------------------------------------------------------------
-10x10 ints
+3x3x3 ints
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
@@ -1542,18 +1010,17 @@ Generators.tests.cpp:<line number>
 Generators.tests.cpp:<line number>: PASSED:
   CHECK( x < y )
 with expansion:
-  10 < 109
+  3 < 6
 
--------------------------------------------------------------------------------
-10x10 ints
--------------------------------------------------------------------------------
-Generators.tests.cpp:<line number>
-...............................................................................
+Generators.tests.cpp:<line number>: PASSED:
+  CHECK( y < z )
+with expansion:
+  6 < 9
 
 Generators.tests.cpp:<line number>: PASSED:
-  CHECK( x < y )
+  REQUIRE( x < z )
 with expansion:
-  10 < 110
+  3 < 9
 
 -------------------------------------------------------------------------------
 A METHOD_AS_TEST_CASE based test run that fails
@@ -3384,382 +2851,794 @@ Matchers.tests.cpp:<line number>: PASSED:
   REQUIRE_THROWS_AS( WithinULP(1.f, -1), std::domain_error )
 
 -------------------------------------------------------------------------------
-Generators
+Generators -- adapters
+  Filtering by predicate
+-------------------------------------------------------------------------------
+Generators.tests.cpp:<line number>
+...............................................................................
+
+Generators.tests.cpp:<line number>: PASSED:
+  REQUIRE( i % 2 == 0 )
+with expansion:
+  0 == 0
+
+-------------------------------------------------------------------------------
+Generators -- adapters
+  Filtering by predicate
+-------------------------------------------------------------------------------
+Generators.tests.cpp:<line number>
+...............................................................................
+
+Generators.tests.cpp:<line number>: PASSED:
+  REQUIRE( i % 2 == 0 )
+with expansion:
+  0 == 0
+
+-------------------------------------------------------------------------------
+Generators -- adapters
+  Filtering by predicate
+-------------------------------------------------------------------------------
+Generators.tests.cpp:<line number>
+...............................................................................
+
+Generators.tests.cpp:<line number>: PASSED:
+  REQUIRE( i % 2 == 0 )
+with expansion:
+  0 == 0
+
+-------------------------------------------------------------------------------
+Generators -- adapters
+  Shortening a range
+-------------------------------------------------------------------------------
+Generators.tests.cpp:<line number>
+...............................................................................
+
+Generators.tests.cpp:<line number>: PASSED:
+  REQUIRE( i < 4 )
+with expansion:
+  1 < 4
+
+-------------------------------------------------------------------------------
+Generators -- adapters
+  Shortening a range
+-------------------------------------------------------------------------------
+Generators.tests.cpp:<line number>
+...............................................................................
+
+Generators.tests.cpp:<line number>: PASSED:
+  REQUIRE( i < 4 )
+with expansion:
+  2 < 4
+
+-------------------------------------------------------------------------------
+Generators -- adapters
+  Shortening a range
+-------------------------------------------------------------------------------
+Generators.tests.cpp:<line number>
+...............................................................................
+
+Generators.tests.cpp:<line number>: PASSED:
+  REQUIRE( i < 4 )
+with expansion:
+  3 < 4
+
+-------------------------------------------------------------------------------
+Generators -- adapters
+  Transforming elements
+  Same type
+-------------------------------------------------------------------------------
+Generators.tests.cpp:<line number>
+...............................................................................
+
+Generators.tests.cpp:<line number>: PASSED:
+  REQUIRE( i % 2 == 0 )
+with expansion:
+  0 == 0
+
+-------------------------------------------------------------------------------
+Generators -- adapters
+  Transforming elements
+  Same type
+-------------------------------------------------------------------------------
+Generators.tests.cpp:<line number>
+...............................................................................
+
+Generators.tests.cpp:<line number>: PASSED:
+  REQUIRE( i % 2 == 0 )
+with expansion:
+  0 == 0
+
+-------------------------------------------------------------------------------
+Generators -- adapters
+  Transforming elements
+  Same type
+-------------------------------------------------------------------------------
+Generators.tests.cpp:<line number>
+...............................................................................
+
+Generators.tests.cpp:<line number>: PASSED:
+  REQUIRE( i % 2 == 0 )
+with expansion:
+  0 == 0
+
+-------------------------------------------------------------------------------
+Generators -- adapters
+  Transforming elements
+  Different type
+-------------------------------------------------------------------------------
+Generators.tests.cpp:<line number>
+...............................................................................
+
+Generators.tests.cpp:<line number>: PASSED:
+  REQUIRE( i.size() == 1 )
+with expansion:
+  1 == 1
+
+-------------------------------------------------------------------------------
+Generators -- adapters
+  Transforming elements
+  Different type
+-------------------------------------------------------------------------------
+Generators.tests.cpp:<line number>
+...............................................................................
+
+Generators.tests.cpp:<line number>: PASSED:
+  REQUIRE( i.size() == 1 )
+with expansion:
+  1 == 1
+
+-------------------------------------------------------------------------------
+Generators -- adapters
+  Transforming elements
+  Different type
+-------------------------------------------------------------------------------
+Generators.tests.cpp:<line number>
+...............................................................................
+
+Generators.tests.cpp:<line number>: PASSED:
+  REQUIRE( i.size() == 1 )
+with expansion:
+  1 == 1
+
+-------------------------------------------------------------------------------
+Generators -- adapters
+  Repeating a generator
+-------------------------------------------------------------------------------
+Generators.tests.cpp:<line number>
+...............................................................................
+
+Generators.tests.cpp:<line number>: PASSED:
+  REQUIRE( j > 0 )
+with expansion:
+  1 > 0
+
+-------------------------------------------------------------------------------
+Generators -- adapters
+  Repeating a generator
+-------------------------------------------------------------------------------
+Generators.tests.cpp:<line number>
+...............................................................................
+
+Generators.tests.cpp:<line number>: PASSED:
+  REQUIRE( j > 0 )
+with expansion:
+  2 > 0
+
+-------------------------------------------------------------------------------
+Generators -- adapters
+  Repeating a generator
+-------------------------------------------------------------------------------
+Generators.tests.cpp:<line number>
+...............................................................................
+
+Generators.tests.cpp:<line number>: PASSED:
+  REQUIRE( j > 0 )
+with expansion:
+  3 > 0
+
+-------------------------------------------------------------------------------
+Generators -- adapters
+  Repeating a generator
+-------------------------------------------------------------------------------
+Generators.tests.cpp:<line number>
+...............................................................................
+
+Generators.tests.cpp:<line number>: PASSED:
+  REQUIRE( j > 0 )
+with expansion:
+  1 > 0
+
+-------------------------------------------------------------------------------
+Generators -- adapters
+  Repeating a generator
+-------------------------------------------------------------------------------
+Generators.tests.cpp:<line number>
+...............................................................................
+
+Generators.tests.cpp:<line number>: PASSED:
+  REQUIRE( j > 0 )
+with expansion:
+  2 > 0
+
+-------------------------------------------------------------------------------
+Generators -- adapters
+  Repeating a generator
+-------------------------------------------------------------------------------
+Generators.tests.cpp:<line number>
+...............................................................................
+
+Generators.tests.cpp:<line number>: PASSED:
+  REQUIRE( j > 0 )
+with expansion:
+  3 > 0
+
+-------------------------------------------------------------------------------
+Generators -- simple
   one
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
 
 Generators.tests.cpp:<line number>: PASSED:
-with messages:
-  i := "a"
-  j := 8
+  REQUIRE( j < i )
+with expansion:
+  -3 < 1
 
 -------------------------------------------------------------------------------
-Generators
+Generators -- simple
   one
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
 
 Generators.tests.cpp:<line number>: PASSED:
-with messages:
-  i := "a"
-  j := 9
+  REQUIRE( j < i )
+with expansion:
+  -2 < 1
 
 -------------------------------------------------------------------------------
-Generators
+Generators -- simple
   one
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
 
 Generators.tests.cpp:<line number>: PASSED:
-with messages:
-  i := "a"
-  j := 10
+  REQUIRE( j < i )
+with expansion:
+  -1 < 1
 
 -------------------------------------------------------------------------------
-Generators
-  one
+Generators -- simple
+  two
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
 
 Generators.tests.cpp:<line number>: PASSED:
-with messages:
-  i := "a"
-  j := 2
+  REQUIRE( 4u * i > str.size() )
+with expansion:
+  4 > 1
 
 -------------------------------------------------------------------------------
-Generators
+Generators -- simple
   two
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
 
 Generators.tests.cpp:<line number>: PASSED:
-with messages:
-  i := "a"
-  j := 3.141
+  REQUIRE( 4u * i > str.size() )
+with expansion:
+  4 > 2
 
 -------------------------------------------------------------------------------
-Generators
+Generators -- simple
   two
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
 
 Generators.tests.cpp:<line number>: PASSED:
-with messages:
-  i := "a"
-  j := 1.379
+  REQUIRE( 4u * i > str.size() )
+with expansion:
+  4 > 3
 
 -------------------------------------------------------------------------------
-Generators
+Generators -- simple
   one
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
 
 Generators.tests.cpp:<line number>: PASSED:
-with messages:
-  i := "b"
-  j := 8
+  REQUIRE( j < i )
+with expansion:
+  -3 < 2
 
 -------------------------------------------------------------------------------
-Generators
+Generators -- simple
   one
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
 
 Generators.tests.cpp:<line number>: PASSED:
-with messages:
-  i := "b"
-  j := 9
+  REQUIRE( j < i )
+with expansion:
+  -2 < 2
 
 -------------------------------------------------------------------------------
-Generators
+Generators -- simple
   one
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
 
 Generators.tests.cpp:<line number>: PASSED:
-with messages:
-  i := "b"
-  j := 10
+  REQUIRE( j < i )
+with expansion:
+  -1 < 2
 
 -------------------------------------------------------------------------------
-Generators
-  one
+Generators -- simple
+  two
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
 
 Generators.tests.cpp:<line number>: PASSED:
-with messages:
-  i := "b"
-  j := 2
+  REQUIRE( 4u * i > str.size() )
+with expansion:
+  8 > 1
 
 -------------------------------------------------------------------------------
-Generators
+Generators -- simple
   two
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
 
 Generators.tests.cpp:<line number>: PASSED:
-with messages:
-  i := "b"
-  j := 3.141
+  REQUIRE( 4u * i > str.size() )
+with expansion:
+  8 > 2
 
 -------------------------------------------------------------------------------
-Generators
+Generators -- simple
   two
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
 
 Generators.tests.cpp:<line number>: PASSED:
-with messages:
-  i := "b"
-  j := 1.379
+  REQUIRE( 4u * i > str.size() )
+with expansion:
+  8 > 3
 
 -------------------------------------------------------------------------------
-Generators
+Generators -- simple
   one
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
 
 Generators.tests.cpp:<line number>: PASSED:
-with messages:
-  i := "c"
-  j := 8
+  REQUIRE( j < i )
+with expansion:
+  -3 < 3
 
 -------------------------------------------------------------------------------
-Generators
+Generators -- simple
   one
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
 
 Generators.tests.cpp:<line number>: PASSED:
-with messages:
-  i := "c"
-  j := 9
+  REQUIRE( j < i )
+with expansion:
+  -2 < 3
 
 -------------------------------------------------------------------------------
-Generators
+Generators -- simple
   one
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
 
 Generators.tests.cpp:<line number>: PASSED:
-with messages:
-  i := "c"
-  j := 10
+  REQUIRE( j < i )
+with expansion:
+  -1 < 3
 
 -------------------------------------------------------------------------------
-Generators
-  one
+Generators -- simple
+  two
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
 
 Generators.tests.cpp:<line number>: PASSED:
-with messages:
-  i := "c"
-  j := 2
+  REQUIRE( 4u * i > str.size() )
+with expansion:
+  12 > 1
 
 -------------------------------------------------------------------------------
-Generators
+Generators -- simple
   two
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
 
 Generators.tests.cpp:<line number>: PASSED:
-with messages:
-  i := "c"
-  j := 3.141
+  REQUIRE( 4u * i > str.size() )
+with expansion:
+  12 > 2
 
 -------------------------------------------------------------------------------
-Generators
+Generators -- simple
   two
 -------------------------------------------------------------------------------
 Generators.tests.cpp:<line number>
 ...............................................................................
 
 Generators.tests.cpp:<line number>: PASSED:
-with messages:
-  i := "c"
-  j := 1.379
+  REQUIRE( 4u * i > str.size() )
+with expansion:
+  12 > 3
 
 -------------------------------------------------------------------------------
-Generators impl
-  range
+Generators internals
+  Single value
 -------------------------------------------------------------------------------
 GeneratorsImpl.tests.cpp:<line number>
 ...............................................................................
 
 GeneratorsImpl.tests.cpp:<line number>: PASSED:
-  CHECK( gen.size() == 2 )
+  REQUIRE( gen.get() == 123 )
 with expansion:
-  2 == 2
+  123 == 123
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE_FALSE( gen.next() )
+with expansion:
+  !false
+
+-------------------------------------------------------------------------------
+Generators internals
+  Preset values
+-------------------------------------------------------------------------------
+GeneratorsImpl.tests.cpp:<line number>
+...............................................................................
 
 GeneratorsImpl.tests.cpp:<line number>: PASSED:
-  CHECK( gen[0] == 1 )
+  REQUIRE( gen.get() == 1 )
 with expansion:
   1 == 1
 
 GeneratorsImpl.tests.cpp:<line number>: PASSED:
-  CHECK( gen[1] == 2 )
+  REQUIRE( gen.next() )
 with expansion:
-  2 == 2
+  true
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE( gen.get() == 3 )
+with expansion:
+  3 == 3
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE( gen.next() )
+with expansion:
+  true
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE( gen.get() == 5 )
+with expansion:
+  5 == 5
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE_FALSE( gen.next() )
+with expansion:
+  !false
 
 -------------------------------------------------------------------------------
-Generators impl
-  fixed values
+Generators internals
+  Generator combinator
 -------------------------------------------------------------------------------
 GeneratorsImpl.tests.cpp:<line number>
 ...............................................................................
 
 GeneratorsImpl.tests.cpp:<line number>: PASSED:
-  CHECK( gen.size() == 4 )
+  REQUIRE( gen.get() == 1 )
 with expansion:
-  4 == 4
+  1 == 1
 
 GeneratorsImpl.tests.cpp:<line number>: PASSED:
-  CHECK( gen[0] == 3 )
+  REQUIRE( gen.next() )
 with expansion:
-  3 == 3
+  true
 
 GeneratorsImpl.tests.cpp:<line number>: PASSED:
-  CHECK( gen[1] == 1 )
+  REQUIRE( gen.get() == 5 )
 with expansion:
-  1 == 1
+  5 == 5
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE( gen.next() )
+with expansion:
+  true
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE( gen.get() == 2 )
+with expansion:
+  2 == 2
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE( gen.next() )
+with expansion:
+  true
 
 GeneratorsImpl.tests.cpp:<line number>: PASSED:
-  CHECK( gen[2] == 4 )
+  REQUIRE( gen.get() == 4 )
 with expansion:
   4 == 4
 
 GeneratorsImpl.tests.cpp:<line number>: PASSED:
-  CHECK( gen[3] == 1 )
+  REQUIRE( gen.next() )
 with expansion:
-  1 == 1
+  true
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE( gen.get() == 0 )
+with expansion:
+  0 == 0
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE_FALSE( gen.next() )
+with expansion:
+  !false
 
 -------------------------------------------------------------------------------
-Generators impl
-  combined
+Generators internals
+  Explicitly typed generator sequence
 -------------------------------------------------------------------------------
 GeneratorsImpl.tests.cpp:<line number>
 ...............................................................................
 
 GeneratorsImpl.tests.cpp:<line number>: PASSED:
-  CHECK( gen.size() == 4 )
+  REQUIRE( gen.get().size() == 2 )
 with expansion:
-  4 == 4
+  2 == 2
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE( gen.get() == "aa" )
+with expansion:
+  "aa" == "aa"
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE( gen.next() )
+with expansion:
+  true
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE( gen.get() == "bb" )
+with expansion:
+  "bb" == "bb"
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE( gen.next() )
+with expansion:
+  true
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE( gen.get() == "cc" )
+with expansion:
+  "cc" == "cc"
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE_FALSE( gen.next() )
+with expansion:
+  !false
+
+-------------------------------------------------------------------------------
+Generators internals
+  Filter generator
+-------------------------------------------------------------------------------
+GeneratorsImpl.tests.cpp:<line number>
+...............................................................................
 
 GeneratorsImpl.tests.cpp:<line number>: PASSED:
-  CHECK( gen[0] == 1 )
+  REQUIRE( gen.get() == 1 )
 with expansion:
   1 == 1
 
 GeneratorsImpl.tests.cpp:<line number>: PASSED:
-  CHECK( gen[1] == 2 )
+  REQUIRE( gen.next() )
 with expansion:
-  2 == 2
+  true
 
 GeneratorsImpl.tests.cpp:<line number>: PASSED:
-  CHECK( gen[2] == 9 )
+  REQUIRE( gen.get() == 3 )
 with expansion:
-  9 == 9
+  3 == 3
 
 GeneratorsImpl.tests.cpp:<line number>: PASSED:
-  CHECK( gen[3] == 7 )
+  REQUIRE_FALSE( gen.next() )
 with expansion:
-  7 == 7
+  !false
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE_THROWS_AS( filter([] (int) { return false; }, value(1)), Catch::GeneratorException )
 
 -------------------------------------------------------------------------------
-Generators impl
-  values
+Generators internals
+  Take generator
+  Take less
 -------------------------------------------------------------------------------
 GeneratorsImpl.tests.cpp:<line number>
 ...............................................................................
 
 GeneratorsImpl.tests.cpp:<line number>: PASSED:
-  CHECK( gen.size() == 2 )
+  REQUIRE( gen.get() == 1 )
+with expansion:
+  1 == 1
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE( gen.next() )
+with expansion:
+  true
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE( gen.get() == 2 )
 with expansion:
   2 == 2
 
 GeneratorsImpl.tests.cpp:<line number>: PASSED:
-  CHECK( gen[0] == 3 )
+  REQUIRE_FALSE( gen.next() )
 with expansion:
-  3 == 3
+  !false
+
+-------------------------------------------------------------------------------
+Generators internals
+  Take generator
+  Take more
+-------------------------------------------------------------------------------
+GeneratorsImpl.tests.cpp:<line number>
+...............................................................................
 
 GeneratorsImpl.tests.cpp:<line number>: PASSED:
-  CHECK( gen[1] == 1 )
+  REQUIRE( gen.get() == 1 )
 with expansion:
   1 == 1
 
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE_FALSE( gen.next() )
+with expansion:
+  !false
+
 -------------------------------------------------------------------------------
-Generators impl
-  values2
+Generators internals
+  Map
 -------------------------------------------------------------------------------
 GeneratorsImpl.tests.cpp:<line number>
 ...............................................................................
 
 GeneratorsImpl.tests.cpp:<line number>: PASSED:
-  CHECK( gen.size() == 2 )
+  REQUIRE( gen.get() == 2.0 )
 with expansion:
-  2 == 2
+  2.0 == 2.0
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE( gen.next() )
+with expansion:
+  true
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE( gen.get() == 4.0 )
+with expansion:
+  4.0 == 4.0
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE( gen.next() )
+with expansion:
+  true
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE( gen.get() == 6.0 )
+with expansion:
+  6.0 == 6.0
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE_FALSE( gen.next() )
+with expansion:
+  !false
+
+-------------------------------------------------------------------------------
+Generators internals
+  Repeat
+  Singular repeat
+-------------------------------------------------------------------------------
+GeneratorsImpl.tests.cpp:<line number>
+...............................................................................
 
 GeneratorsImpl.tests.cpp:<line number>: PASSED:
-  CHECK( gen[0] == 3 )
+  REQUIRE( gen.get() == 3 )
 with expansion:
   3 == 3
 
 GeneratorsImpl.tests.cpp:<line number>: PASSED:
-  CHECK( gen[1] == 1 )
+  REQUIRE_FALSE( gen.next() )
 with expansion:
-  1 == 1
+  !false
 
 -------------------------------------------------------------------------------
-Generators impl
-  type erasure
+Generators internals
+  Repeat
+  Actual repeat
 -------------------------------------------------------------------------------
 GeneratorsImpl.tests.cpp:<line number>
 ...............................................................................
 
 GeneratorsImpl.tests.cpp:<line number>: PASSED:
-  CHECK( base->size() == 4 )
+  REQUIRE( gen.get() == 1 )
 with expansion:
-  4 == 4
+  1 == 1
 
 GeneratorsImpl.tests.cpp:<line number>: PASSED:
-  REQUIRE( typed )
+  REQUIRE( gen.next() )
 with expansion:
-  0x<hex digits>
+  true
 
 GeneratorsImpl.tests.cpp:<line number>: PASSED:
-  CHECK( typed->size() == 4 )
+  REQUIRE( gen.get() == 2 )
 with expansion:
-  4 == 4
+  2 == 2
 
 GeneratorsImpl.tests.cpp:<line number>: PASSED:
-  CHECK( (*typed)[0] == 7 )
+  REQUIRE( gen.next() )
 with expansion:
-  7 == 7
+  true
 
 GeneratorsImpl.tests.cpp:<line number>: PASSED:
-  CHECK( (*typed)[3] == 11 )
+  REQUIRE( gen.get() == 3 )
 with expansion:
-  11 == 11
+  3 == 3
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE( gen.next() )
+with expansion:
+  true
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE( gen.get() == 1 )
+with expansion:
+  1 == 1
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE( gen.next() )
+with expansion:
+  true
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE( gen.get() == 2 )
+with expansion:
+  2 == 2
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE( gen.next() )
+with expansion:
+  true
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE( gen.get() == 3 )
+with expansion:
+  3 == 3
+
+GeneratorsImpl.tests.cpp:<line number>: PASSED:
+  REQUIRE_FALSE( gen.next() )
+with expansion:
+  !false
 
 -------------------------------------------------------------------------------
 Greater-than inequalities with different epsilons
@@ -9747,6 +9626,50 @@ Generators.tests.cpp:<line number>: PASSED:
 with expansion:
   4 == 4
 
+-------------------------------------------------------------------------------
+tables
+-------------------------------------------------------------------------------
+Generators.tests.cpp:<line number>
+...............................................................................
+
+Generators.tests.cpp:<line number>: PASSED:
+  REQUIRE( strlen(std::get<0>(data)) == static_cast<size_t>(std::get<1>(data)) )
+with expansion:
+  5 == 5
+
+-------------------------------------------------------------------------------
+tables
+-------------------------------------------------------------------------------
+Generators.tests.cpp:<line number>
+...............................................................................
+
+Generators.tests.cpp:<line number>: PASSED:
+  REQUIRE( strlen(std::get<0>(data)) == static_cast<size_t>(std::get<1>(data)) )
+with expansion:
+  6 == 6
+
+-------------------------------------------------------------------------------
+tables
+-------------------------------------------------------------------------------
+Generators.tests.cpp:<line number>
+...............................................................................
+
+Generators.tests.cpp:<line number>: PASSED:
+  REQUIRE( strlen(std::get<0>(data)) == static_cast<size_t>(std::get<1>(data)) )
+with expansion:
+  5 == 5
+
+-------------------------------------------------------------------------------
+tables
+-------------------------------------------------------------------------------
+Generators.tests.cpp:<line number>
+...............................................................................
+
+Generators.tests.cpp:<line number>: PASSED:
+  REQUIRE( strlen(std::get<0>(data)) == static_cast<size_t>(std::get<1>(data)) )
+with expansion:
+  6 == 6
+
 -------------------------------------------------------------------------------
 thrown std::strings are translated
 -------------------------------------------------------------------------------
@@ -10224,6 +10147,6 @@ Misc.tests.cpp:<line number>
 Misc.tests.cpp:<line number>: PASSED:
 
 ===============================================================================
-test cases:  243 |  170 passed |  69 failed |  4 failed as expected
-assertions: 1276 | 1126 passed | 129 failed | 21 failed as expected
+test cases:  245 |  172 passed |  69 failed |  4 failed as expected
+assertions: 1311 | 1161 passed | 129 failed | 21 failed as expected
 
diff --git a/projects/SelfTest/Baselines/junit.sw.approved.txt b/projects/SelfTest/Baselines/junit.sw.approved.txt
index 17cc828110..a245a37ab7 100644
--- a/projects/SelfTest/Baselines/junit.sw.approved.txt
+++ b/projects/SelfTest/Baselines/junit.sw.approved.txt
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <testsuitesloose text artifact
 >
-  <testsuite name="<exe-name>" errors="17" failures="113" tests="1277" hostname="tbd" time="{duration}" timestamp="{iso8601-timestamp}">
+  <testsuite name="<exe-name>" errors="17" failures="113" tests="1312" hostname="tbd" time="{duration}" timestamp="{iso8601-timestamp}">
     <testcase classname="<exe-name>.global" name="# A test name that starts with a #" time="{duration}"/>
     <testcase classname="<exe-name>.global" name="#1005: Comparing pointer to int and long (NULL can be either on various systems)" time="{duration}"/>
     <testcase classname="<exe-name>.global" name="#1027" time="{duration}"/>
@@ -70,7 +70,7 @@ Condition.tests.cpp:<line number>
     <testcase classname="<exe-name>.global" name="(unimplemented) static bools can be evaluated/negation" time="{duration}"/>
     <testcase classname="<exe-name>.global" name="(unimplemented) static bools can be evaluated/double negation" time="{duration}"/>
     <testcase classname="<exe-name>.global" name="(unimplemented) static bools can be evaluated/direct" time="{duration}"/>
-    <testcase classname="<exe-name>.global" name="10x10 ints" time="{duration}"/>
+    <testcase classname="<exe-name>.global" name="3x3x3 ints" time="{duration}"/>
     <testcase classname="<exe-name>.TestClass" name="A METHOD_AS_TEST_CASE based test run that fails" time="{duration}">
       <failure message="&quot;hello&quot; == &quot;world&quot;" type="REQUIRE">
 Class.tests.cpp:<line number>
@@ -339,14 +339,23 @@ Message.tests.cpp:<line number>
     <testcase classname="<exe-name>.global" name="Floating point matchers: float/ULPs" time="{duration}"/>
     <testcase classname="<exe-name>.global" name="Floating point matchers: float/Composed" time="{duration}"/>
     <testcase classname="<exe-name>.global" name="Floating point matchers: float/Constructor validation" time="{duration}"/>
-    <testcase classname="<exe-name>.global" name="Generators/one" time="{duration}"/>
-    <testcase classname="<exe-name>.global" name="Generators/two" time="{duration}"/>
-    <testcase classname="<exe-name>.global" name="Generators impl/range" time="{duration}"/>
-    <testcase classname="<exe-name>.global" name="Generators impl/fixed values" time="{duration}"/>
-    <testcase classname="<exe-name>.global" name="Generators impl/combined" time="{duration}"/>
-    <testcase classname="<exe-name>.global" name="Generators impl/values" time="{duration}"/>
-    <testcase classname="<exe-name>.global" name="Generators impl/values2" time="{duration}"/>
-    <testcase classname="<exe-name>.global" name="Generators impl/type erasure" time="{duration}"/>
+    <testcase classname="<exe-name>.global" name="Generators -- adapters/Filtering by predicate" time="{duration}"/>
+    <testcase classname="<exe-name>.global" name="Generators -- adapters/Shortening a range" time="{duration}"/>
+    <testcase classname="<exe-name>.global" name="Generators -- adapters/Transforming elements/Same type" time="{duration}"/>
+    <testcase classname="<exe-name>.global" name="Generators -- adapters/Transforming elements/Different type" time="{duration}"/>
+    <testcase classname="<exe-name>.global" name="Generators -- adapters/Repeating a generator" time="{duration}"/>
+    <testcase classname="<exe-name>.global" name="Generators -- simple/one" time="{duration}"/>
+    <testcase classname="<exe-name>.global" name="Generators -- simple/two" time="{duration}"/>
+    <testcase classname="<exe-name>.global" name="Generators internals/Single value" time="{duration}"/>
+    <testcase classname="<exe-name>.global" name="Generators internals/Preset values" time="{duration}"/>
+    <testcase classname="<exe-name>.global" name="Generators internals/Generator combinator" time="{duration}"/>
+    <testcase classname="<exe-name>.global" name="Generators internals/Explicitly typed generator sequence" time="{duration}"/>
+    <testcase classname="<exe-name>.global" name="Generators internals/Filter generator" time="{duration}"/>
+    <testcase classname="<exe-name>.global" name="Generators internals/Take generator/Take less" time="{duration}"/>
+    <testcase classname="<exe-name>.global" name="Generators internals/Take generator/Take more" time="{duration}"/>
+    <testcase classname="<exe-name>.global" name="Generators internals/Map" time="{duration}"/>
+    <testcase classname="<exe-name>.global" name="Generators internals/Repeat/Singular repeat" time="{duration}"/>
+    <testcase classname="<exe-name>.global" name="Generators internals/Repeat/Actual repeat" time="{duration}"/>
     <testcase classname="<exe-name>.global" name="Greater-than inequalities with different epsilons" time="{duration}"/>
     <testcase classname="<exe-name>.global" name="INFO and WARN do not abort tests" time="{duration}"/>
     <testcase classname="<exe-name>.global" name="INFO gets logged on failure" time="{duration}">
@@ -938,6 +947,7 @@ Tricky.tests.cpp:<line number>
     <testcase classname="<exe-name>.global" name="stringify( vectors&lt;has_maker_and_operator> )" time="{duration}"/>
     <testcase classname="<exe-name>.global" name="stringify( vectors&lt;has_operator> )" time="{duration}"/>
     <testcase classname="<exe-name>.global" name="strlen3" time="{duration}"/>
+    <testcase classname="<exe-name>.global" name="tables" time="{duration}"/>
     <testcase classname="<exe-name>.global" name="thrown std::strings are translated" time="{duration}">
       <error type="TEST_CASE">
 Why would you throw a std::string?
diff --git a/projects/SelfTest/Baselines/xml.sw.approved.txt b/projects/SelfTest/Baselines/xml.sw.approved.txt
index 497d81684a..6558d6f286 100644
--- a/projects/SelfTest/Baselines/xml.sw.approved.txt
+++ b/projects/SelfTest/Baselines/xml.sw.approved.txt
@@ -522,181 +522,29 @@
       </Section>
       <OverallResult success="true"/>
     </TestCase>
-    <TestCase name="10x10 ints" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+    <TestCase name="3x3x3 ints" tags="[generators]" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
           x &lt; y
         </Original>
         <Expanded>
-          1 &lt; 101
+          1 &lt; 4
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
-        </Original>
-        <Expanded>
-          1 &lt; 102
-        </Expanded>
-      </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
-        <Original>
-          x &lt; y
-        </Original>
-        <Expanded>
-          1 &lt; 103
-        </Expanded>
-      </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
-        <Original>
-          x &lt; y
-        </Original>
-        <Expanded>
-          1 &lt; 104
-        </Expanded>
-      </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
-        <Original>
-          x &lt; y
-        </Original>
-        <Expanded>
-          1 &lt; 105
-        </Expanded>
-      </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
-        <Original>
-          x &lt; y
-        </Original>
-        <Expanded>
-          1 &lt; 106
-        </Expanded>
-      </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
-        <Original>
-          x &lt; y
-        </Original>
-        <Expanded>
-          1 &lt; 107
-        </Expanded>
-      </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
-        <Original>
-          x &lt; y
-        </Original>
-        <Expanded>
-          1 &lt; 108
-        </Expanded>
-      </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
-        <Original>
-          x &lt; y
-        </Original>
-        <Expanded>
-          1 &lt; 109
-        </Expanded>
-      </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
-        <Original>
-          x &lt; y
-        </Original>
-        <Expanded>
-          1 &lt; 110
-        </Expanded>
-      </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
-        <Original>
-          x &lt; y
-        </Original>
-        <Expanded>
-          2 &lt; 101
-        </Expanded>
-      </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
-        <Original>
-          x &lt; y
-        </Original>
-        <Expanded>
-          2 &lt; 102
-        </Expanded>
-      </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
-        <Original>
-          x &lt; y
-        </Original>
-        <Expanded>
-          2 &lt; 103
-        </Expanded>
-      </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
-        <Original>
-          x &lt; y
-        </Original>
-        <Expanded>
-          2 &lt; 104
-        </Expanded>
-      </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
-        <Original>
-          x &lt; y
-        </Original>
-        <Expanded>
-          2 &lt; 105
-        </Expanded>
-      </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
-        <Original>
-          x &lt; y
-        </Original>
-        <Expanded>
-          2 &lt; 106
-        </Expanded>
-      </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
-        <Original>
-          x &lt; y
-        </Original>
-        <Expanded>
-          2 &lt; 107
-        </Expanded>
-      </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
-        <Original>
-          x &lt; y
-        </Original>
-        <Expanded>
-          2 &lt; 108
-        </Expanded>
-      </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
-        <Original>
-          x &lt; y
-        </Original>
-        <Expanded>
-          2 &lt; 109
-        </Expanded>
-      </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
-        <Original>
-          x &lt; y
-        </Original>
-        <Expanded>
-          2 &lt; 110
-        </Expanded>
-      </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
-        <Original>
-          x &lt; y
+          y &lt; z
         </Original>
         <Expanded>
-          3 &lt; 101
+          4 &lt; 7
         </Expanded>
       </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          x &lt; z
         </Original>
         <Expanded>
-          3 &lt; 102
+          1 &lt; 7
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
@@ -704,23 +552,23 @@
           x &lt; y
         </Original>
         <Expanded>
-          3 &lt; 103
+          1 &lt; 4
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          y &lt; z
         </Original>
         <Expanded>
-          3 &lt; 104
+          4 &lt; 8
         </Expanded>
       </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          x &lt; z
         </Original>
         <Expanded>
-          3 &lt; 105
+          1 &lt; 8
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
@@ -728,23 +576,23 @@
           x &lt; y
         </Original>
         <Expanded>
-          3 &lt; 106
+          1 &lt; 4
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          y &lt; z
         </Original>
         <Expanded>
-          3 &lt; 107
+          4 &lt; 9
         </Expanded>
       </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          x &lt; z
         </Original>
         <Expanded>
-          3 &lt; 108
+          1 &lt; 9
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
@@ -752,23 +600,23 @@
           x &lt; y
         </Original>
         <Expanded>
-          3 &lt; 109
+          1 &lt; 5
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          y &lt; z
         </Original>
         <Expanded>
-          3 &lt; 110
+          5 &lt; 7
         </Expanded>
       </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          x &lt; z
         </Original>
         <Expanded>
-          4 &lt; 101
+          1 &lt; 7
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
@@ -776,23 +624,23 @@
           x &lt; y
         </Original>
         <Expanded>
-          4 &lt; 102
+          1 &lt; 5
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          y &lt; z
         </Original>
         <Expanded>
-          4 &lt; 103
+          5 &lt; 8
         </Expanded>
       </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          x &lt; z
         </Original>
         <Expanded>
-          4 &lt; 104
+          1 &lt; 8
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
@@ -800,23 +648,23 @@
           x &lt; y
         </Original>
         <Expanded>
-          4 &lt; 105
+          1 &lt; 5
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          y &lt; z
         </Original>
         <Expanded>
-          4 &lt; 106
+          5 &lt; 9
         </Expanded>
       </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          x &lt; z
         </Original>
         <Expanded>
-          4 &lt; 107
+          1 &lt; 9
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
@@ -824,23 +672,23 @@
           x &lt; y
         </Original>
         <Expanded>
-          4 &lt; 108
+          1 &lt; 6
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          y &lt; z
         </Original>
         <Expanded>
-          4 &lt; 109
+          6 &lt; 7
         </Expanded>
       </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          x &lt; z
         </Original>
         <Expanded>
-          4 &lt; 110
+          1 &lt; 7
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
@@ -848,23 +696,23 @@
           x &lt; y
         </Original>
         <Expanded>
-          5 &lt; 101
+          1 &lt; 6
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          y &lt; z
         </Original>
         <Expanded>
-          5 &lt; 102
+          6 &lt; 8
         </Expanded>
       </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          x &lt; z
         </Original>
         <Expanded>
-          5 &lt; 103
+          1 &lt; 8
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
@@ -872,23 +720,23 @@
           x &lt; y
         </Original>
         <Expanded>
-          5 &lt; 104
+          1 &lt; 6
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          y &lt; z
         </Original>
         <Expanded>
-          5 &lt; 105
+          6 &lt; 9
         </Expanded>
       </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          x &lt; z
         </Original>
         <Expanded>
-          5 &lt; 106
+          1 &lt; 9
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
@@ -896,23 +744,23 @@
           x &lt; y
         </Original>
         <Expanded>
-          5 &lt; 107
+          2 &lt; 4
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          y &lt; z
         </Original>
         <Expanded>
-          5 &lt; 108
+          4 &lt; 7
         </Expanded>
       </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          x &lt; z
         </Original>
         <Expanded>
-          5 &lt; 109
+          2 &lt; 7
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
@@ -920,23 +768,23 @@
           x &lt; y
         </Original>
         <Expanded>
-          5 &lt; 110
+          2 &lt; 4
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          y &lt; z
         </Original>
         <Expanded>
-          6 &lt; 101
+          4 &lt; 8
         </Expanded>
       </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          x &lt; z
         </Original>
         <Expanded>
-          6 &lt; 102
+          2 &lt; 8
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
@@ -944,23 +792,23 @@
           x &lt; y
         </Original>
         <Expanded>
-          6 &lt; 103
+          2 &lt; 4
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          y &lt; z
         </Original>
         <Expanded>
-          6 &lt; 104
+          4 &lt; 9
         </Expanded>
       </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          x &lt; z
         </Original>
         <Expanded>
-          6 &lt; 105
+          2 &lt; 9
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
@@ -968,23 +816,23 @@
           x &lt; y
         </Original>
         <Expanded>
-          6 &lt; 106
+          2 &lt; 5
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          y &lt; z
         </Original>
         <Expanded>
-          6 &lt; 107
+          5 &lt; 7
         </Expanded>
       </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          x &lt; z
         </Original>
         <Expanded>
-          6 &lt; 108
+          2 &lt; 7
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
@@ -992,23 +840,23 @@
           x &lt; y
         </Original>
         <Expanded>
-          6 &lt; 109
+          2 &lt; 5
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          y &lt; z
         </Original>
         <Expanded>
-          6 &lt; 110
+          5 &lt; 8
         </Expanded>
       </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          x &lt; z
         </Original>
         <Expanded>
-          7 &lt; 101
+          2 &lt; 8
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
@@ -1016,23 +864,23 @@
           x &lt; y
         </Original>
         <Expanded>
-          7 &lt; 102
+          2 &lt; 5
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          y &lt; z
         </Original>
         <Expanded>
-          7 &lt; 103
+          5 &lt; 9
         </Expanded>
       </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          x &lt; z
         </Original>
         <Expanded>
-          7 &lt; 104
+          2 &lt; 9
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
@@ -1040,23 +888,23 @@
           x &lt; y
         </Original>
         <Expanded>
-          7 &lt; 105
+          2 &lt; 6
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          y &lt; z
         </Original>
         <Expanded>
-          7 &lt; 106
+          6 &lt; 7
         </Expanded>
       </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          x &lt; z
         </Original>
         <Expanded>
-          7 &lt; 107
+          2 &lt; 7
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
@@ -1064,23 +912,23 @@
           x &lt; y
         </Original>
         <Expanded>
-          7 &lt; 108
+          2 &lt; 6
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          y &lt; z
         </Original>
         <Expanded>
-          7 &lt; 109
+          6 &lt; 8
         </Expanded>
       </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          x &lt; z
         </Original>
         <Expanded>
-          7 &lt; 110
+          2 &lt; 8
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
@@ -1088,23 +936,23 @@
           x &lt; y
         </Original>
         <Expanded>
-          8 &lt; 101
+          2 &lt; 6
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          y &lt; z
         </Original>
         <Expanded>
-          8 &lt; 102
+          6 &lt; 9
         </Expanded>
       </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          x &lt; z
         </Original>
         <Expanded>
-          8 &lt; 103
+          2 &lt; 9
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
@@ -1112,23 +960,23 @@
           x &lt; y
         </Original>
         <Expanded>
-          8 &lt; 104
+          3 &lt; 4
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          y &lt; z
         </Original>
         <Expanded>
-          8 &lt; 105
+          4 &lt; 7
         </Expanded>
       </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          x &lt; z
         </Original>
         <Expanded>
-          8 &lt; 106
+          3 &lt; 7
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
@@ -1136,23 +984,23 @@
           x &lt; y
         </Original>
         <Expanded>
-          8 &lt; 107
+          3 &lt; 4
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          y &lt; z
         </Original>
         <Expanded>
-          8 &lt; 108
+          4 &lt; 8
         </Expanded>
       </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          x &lt; z
         </Original>
         <Expanded>
-          8 &lt; 109
+          3 &lt; 8
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
@@ -1160,23 +1008,23 @@
           x &lt; y
         </Original>
         <Expanded>
-          8 &lt; 110
+          3 &lt; 4
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          y &lt; z
         </Original>
         <Expanded>
-          9 &lt; 101
+          4 &lt; 9
         </Expanded>
       </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          x &lt; z
         </Original>
         <Expanded>
-          9 &lt; 102
+          3 &lt; 9
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
@@ -1184,23 +1032,23 @@
           x &lt; y
         </Original>
         <Expanded>
-          9 &lt; 103
+          3 &lt; 5
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          y &lt; z
         </Original>
         <Expanded>
-          9 &lt; 104
+          5 &lt; 7
         </Expanded>
       </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          x &lt; z
         </Original>
         <Expanded>
-          9 &lt; 105
+          3 &lt; 7
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
@@ -1208,23 +1056,23 @@
           x &lt; y
         </Original>
         <Expanded>
-          9 &lt; 106
+          3 &lt; 5
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          y &lt; z
         </Original>
         <Expanded>
-          9 &lt; 107
+          5 &lt; 8
         </Expanded>
       </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          x &lt; z
         </Original>
         <Expanded>
-          9 &lt; 108
+          3 &lt; 8
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
@@ -1232,23 +1080,23 @@
           x &lt; y
         </Original>
         <Expanded>
-          9 &lt; 109
+          3 &lt; 5
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          y &lt; z
         </Original>
         <Expanded>
-          9 &lt; 110
+          5 &lt; 9
         </Expanded>
       </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          x &lt; z
         </Original>
         <Expanded>
-          10 &lt; 101
+          3 &lt; 9
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
@@ -1256,23 +1104,23 @@
           x &lt; y
         </Original>
         <Expanded>
-          10 &lt; 102
+          3 &lt; 6
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          y &lt; z
         </Original>
         <Expanded>
-          10 &lt; 103
+          6 &lt; 7
         </Expanded>
       </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          x &lt; z
         </Original>
         <Expanded>
-          10 &lt; 104
+          3 &lt; 7
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
@@ -1280,23 +1128,23 @@
           x &lt; y
         </Original>
         <Expanded>
-          10 &lt; 105
+          3 &lt; 6
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          y &lt; z
         </Original>
         <Expanded>
-          10 &lt; 106
+          6 &lt; 8
         </Expanded>
       </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          x &lt; z
         </Original>
         <Expanded>
-          10 &lt; 107
+          3 &lt; 8
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
@@ -1304,23 +1152,23 @@
           x &lt; y
         </Original>
         <Expanded>
-          10 &lt; 108
+          3 &lt; 6
         </Expanded>
       </Expression>
       <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          y &lt; z
         </Original>
         <Expanded>
-          10 &lt; 109
+          6 &lt; 9
         </Expanded>
       </Expression>
-      <Expression success="true" type="CHECK" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
-          x &lt; y
+          x &lt; z
         </Original>
         <Expanded>
-          10 &lt; 110
+          3 &lt; 9
         </Expanded>
       </Expression>
       <OverallResult success="true"/>
@@ -3690,381 +3538,916 @@
       </Section>
       <OverallResult success="true"/>
     </TestCase>
-    <TestCase name="Generators" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
-      <Section name="one" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
-        <Info>
-          i := "a"
-        </Info>
-        <Info>
-          j := 8
-        </Info>
+    <TestCase name="Generators -- adapters" tags="[generators]" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+      <Section name="Filtering by predicate" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+          <Original>
+            i % 2 == 0
+          </Original>
+          <Expanded>
+            0 == 0
+          </Expanded>
+        </Expression>
         <OverallResults successes="1" failures="0" expectedFailures="0"/>
       </Section>
-      <Section name="one" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
-        <Info>
-          i := "a"
-        </Info>
-        <Info>
-          j := 9
-        </Info>
+      <Section name="Filtering by predicate" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+          <Original>
+            i % 2 == 0
+          </Original>
+          <Expanded>
+            0 == 0
+          </Expanded>
+        </Expression>
         <OverallResults successes="1" failures="0" expectedFailures="0"/>
       </Section>
+      <Section name="Filtering by predicate" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+          <Original>
+            i % 2 == 0
+          </Original>
+          <Expanded>
+            0 == 0
+          </Expanded>
+        </Expression>
+        <OverallResults successes="1" failures="0" expectedFailures="0"/>
+      </Section>
+      <Section name="Shortening a range" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+          <Original>
+            i &lt; 4
+          </Original>
+          <Expanded>
+            1 &lt; 4
+          </Expanded>
+        </Expression>
+        <OverallResults successes="1" failures="0" expectedFailures="0"/>
+      </Section>
+      <Section name="Shortening a range" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+          <Original>
+            i &lt; 4
+          </Original>
+          <Expanded>
+            2 &lt; 4
+          </Expanded>
+        </Expression>
+        <OverallResults successes="1" failures="0" expectedFailures="0"/>
+      </Section>
+      <Section name="Shortening a range" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+          <Original>
+            i &lt; 4
+          </Original>
+          <Expanded>
+            3 &lt; 4
+          </Expanded>
+        </Expression>
+        <OverallResults successes="1" failures="0" expectedFailures="0"/>
+      </Section>
+      <Section name="Transforming elements" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+        <Section name="Same type" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+          <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+            <Original>
+              i % 2 == 0
+            </Original>
+            <Expanded>
+              0 == 0
+            </Expanded>
+          </Expression>
+          <OverallResults successes="1" failures="0" expectedFailures="0"/>
+        </Section>
+        <OverallResults successes="1" failures="0" expectedFailures="0"/>
+      </Section>
+      <Section name="Transforming elements" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+        <Section name="Same type" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+          <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+            <Original>
+              i % 2 == 0
+            </Original>
+            <Expanded>
+              0 == 0
+            </Expanded>
+          </Expression>
+          <OverallResults successes="1" failures="0" expectedFailures="0"/>
+        </Section>
+        <OverallResults successes="1" failures="0" expectedFailures="0"/>
+      </Section>
+      <Section name="Transforming elements" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+        <Section name="Same type" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+          <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+            <Original>
+              i % 2 == 0
+            </Original>
+            <Expanded>
+              0 == 0
+            </Expanded>
+          </Expression>
+          <OverallResults successes="1" failures="0" expectedFailures="0"/>
+        </Section>
+        <OverallResults successes="1" failures="0" expectedFailures="0"/>
+      </Section>
+      <Section name="Transforming elements" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+        <Section name="Different type" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+          <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+            <Original>
+              i.size() == 1
+            </Original>
+            <Expanded>
+              1 == 1
+            </Expanded>
+          </Expression>
+          <OverallResults successes="1" failures="0" expectedFailures="0"/>
+        </Section>
+        <OverallResults successes="1" failures="0" expectedFailures="0"/>
+      </Section>
+      <Section name="Transforming elements" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+        <Section name="Different type" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+          <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+            <Original>
+              i.size() == 1
+            </Original>
+            <Expanded>
+              1 == 1
+            </Expanded>
+          </Expression>
+          <OverallResults successes="1" failures="0" expectedFailures="0"/>
+        </Section>
+        <OverallResults successes="1" failures="0" expectedFailures="0"/>
+      </Section>
+      <Section name="Transforming elements" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+        <Section name="Different type" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+          <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+            <Original>
+              i.size() == 1
+            </Original>
+            <Expanded>
+              1 == 1
+            </Expanded>
+          </Expression>
+          <OverallResults successes="1" failures="0" expectedFailures="0"/>
+        </Section>
+        <OverallResults successes="1" failures="0" expectedFailures="0"/>
+      </Section>
+      <Section name="Repeating a generator" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+          <Original>
+            j > 0
+          </Original>
+          <Expanded>
+            1 > 0
+          </Expanded>
+        </Expression>
+        <OverallResults successes="1" failures="0" expectedFailures="0"/>
+      </Section>
+      <Section name="Repeating a generator" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+          <Original>
+            j > 0
+          </Original>
+          <Expanded>
+            2 > 0
+          </Expanded>
+        </Expression>
+        <OverallResults successes="1" failures="0" expectedFailures="0"/>
+      </Section>
+      <Section name="Repeating a generator" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+          <Original>
+            j > 0
+          </Original>
+          <Expanded>
+            3 > 0
+          </Expanded>
+        </Expression>
+        <OverallResults successes="1" failures="0" expectedFailures="0"/>
+      </Section>
+      <Section name="Repeating a generator" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+          <Original>
+            j > 0
+          </Original>
+          <Expanded>
+            1 > 0
+          </Expanded>
+        </Expression>
+        <OverallResults successes="1" failures="0" expectedFailures="0"/>
+      </Section>
+      <Section name="Repeating a generator" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+          <Original>
+            j > 0
+          </Original>
+          <Expanded>
+            2 > 0
+          </Expanded>
+        </Expression>
+        <OverallResults successes="1" failures="0" expectedFailures="0"/>
+      </Section>
+      <Section name="Repeating a generator" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+          <Original>
+            j > 0
+          </Original>
+          <Expanded>
+            3 > 0
+          </Expanded>
+        </Expression>
+        <OverallResults successes="1" failures="0" expectedFailures="0"/>
+      </Section>
+      <OverallResult success="true"/>
+    </TestCase>
+    <TestCase name="Generators -- simple" tags="[generators]" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
       <Section name="one" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
-        <Info>
-          i := "a"
-        </Info>
-        <Info>
-          j := 10
-        </Info>
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+          <Original>
+            j &lt; i
+          </Original>
+          <Expanded>
+            -3 &lt; 1
+          </Expanded>
+        </Expression>
         <OverallResults successes="1" failures="0" expectedFailures="0"/>
       </Section>
       <Section name="one" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
-        <Info>
-          i := "a"
-        </Info>
-        <Info>
-          j := 2
-        </Info>
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+          <Original>
+            j &lt; i
+          </Original>
+          <Expanded>
+            -2 &lt; 1
+          </Expanded>
+        </Expression>
+        <OverallResults successes="1" failures="0" expectedFailures="0"/>
+      </Section>
+      <Section name="one" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+          <Original>
+            j &lt; i
+          </Original>
+          <Expanded>
+            -1 &lt; 1
+          </Expanded>
+        </Expression>
         <OverallResults successes="1" failures="0" expectedFailures="0"/>
       </Section>
       <Section name="two" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
-        <Info>
-          i := "a"
-        </Info>
-        <Info>
-          j := 3.141
-        </Info>
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+          <Original>
+            4u * i > str.size()
+          </Original>
+          <Expanded>
+            4 > 1
+          </Expanded>
+        </Expression>
         <OverallResults successes="1" failures="0" expectedFailures="0"/>
       </Section>
       <Section name="two" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
-        <Info>
-          i := "a"
-        </Info>
-        <Info>
-          j := 1.379
-        </Info>
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+          <Original>
+            4u * i > str.size()
+          </Original>
+          <Expanded>
+            4 > 2
+          </Expanded>
+        </Expression>
         <OverallResults successes="1" failures="0" expectedFailures="0"/>
       </Section>
-      <Section name="one" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
-        <Info>
-          i := "b"
-        </Info>
-        <Info>
-          j := 8
-        </Info>
+      <Section name="two" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+          <Original>
+            4u * i > str.size()
+          </Original>
+          <Expanded>
+            4 > 3
+          </Expanded>
+        </Expression>
         <OverallResults successes="1" failures="0" expectedFailures="0"/>
       </Section>
       <Section name="one" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
-        <Info>
-          i := "b"
-        </Info>
-        <Info>
-          j := 9
-        </Info>
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+          <Original>
+            j &lt; i
+          </Original>
+          <Expanded>
+            -3 &lt; 2
+          </Expanded>
+        </Expression>
         <OverallResults successes="1" failures="0" expectedFailures="0"/>
       </Section>
       <Section name="one" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
-        <Info>
-          i := "b"
-        </Info>
-        <Info>
-          j := 10
-        </Info>
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+          <Original>
+            j &lt; i
+          </Original>
+          <Expanded>
+            -2 &lt; 2
+          </Expanded>
+        </Expression>
         <OverallResults successes="1" failures="0" expectedFailures="0"/>
       </Section>
       <Section name="one" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
-        <Info>
-          i := "b"
-        </Info>
-        <Info>
-          j := 2
-        </Info>
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+          <Original>
+            j &lt; i
+          </Original>
+          <Expanded>
+            -1 &lt; 2
+          </Expanded>
+        </Expression>
         <OverallResults successes="1" failures="0" expectedFailures="0"/>
       </Section>
       <Section name="two" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
-        <Info>
-          i := "b"
-        </Info>
-        <Info>
-          j := 3.141
-        </Info>
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+          <Original>
+            4u * i > str.size()
+          </Original>
+          <Expanded>
+            8 > 1
+          </Expanded>
+        </Expression>
         <OverallResults successes="1" failures="0" expectedFailures="0"/>
       </Section>
       <Section name="two" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
-        <Info>
-          i := "b"
-        </Info>
-        <Info>
-          j := 1.379
-        </Info>
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+          <Original>
+            4u * i > str.size()
+          </Original>
+          <Expanded>
+            8 > 2
+          </Expanded>
+        </Expression>
         <OverallResults successes="1" failures="0" expectedFailures="0"/>
       </Section>
-      <Section name="one" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
-        <Info>
-          i := "c"
-        </Info>
-        <Info>
-          j := 8
-        </Info>
+      <Section name="two" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+          <Original>
+            4u * i > str.size()
+          </Original>
+          <Expanded>
+            8 > 3
+          </Expanded>
+        </Expression>
         <OverallResults successes="1" failures="0" expectedFailures="0"/>
       </Section>
       <Section name="one" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
-        <Info>
-          i := "c"
-        </Info>
-        <Info>
-          j := 9
-        </Info>
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+          <Original>
+            j &lt; i
+          </Original>
+          <Expanded>
+            -3 &lt; 3
+          </Expanded>
+        </Expression>
         <OverallResults successes="1" failures="0" expectedFailures="0"/>
       </Section>
       <Section name="one" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
-        <Info>
-          i := "c"
-        </Info>
-        <Info>
-          j := 10
-        </Info>
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+          <Original>
+            j &lt; i
+          </Original>
+          <Expanded>
+            -2 &lt; 3
+          </Expanded>
+        </Expression>
         <OverallResults successes="1" failures="0" expectedFailures="0"/>
       </Section>
       <Section name="one" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
-        <Info>
-          i := "c"
-        </Info>
-        <Info>
-          j := 2
-        </Info>
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+          <Original>
+            j &lt; i
+          </Original>
+          <Expanded>
+            -1 &lt; 3
+          </Expanded>
+        </Expression>
         <OverallResults successes="1" failures="0" expectedFailures="0"/>
       </Section>
       <Section name="two" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
-        <Info>
-          i := "c"
-        </Info>
-        <Info>
-          j := 3.141
-        </Info>
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+          <Original>
+            4u * i > str.size()
+          </Original>
+          <Expanded>
+            12 > 1
+          </Expanded>
+        </Expression>
         <OverallResults successes="1" failures="0" expectedFailures="0"/>
       </Section>
       <Section name="two" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
-        <Info>
-          i := "c"
-        </Info>
-        <Info>
-          j := 1.379
-        </Info>
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+          <Original>
+            4u * i > str.size()
+          </Original>
+          <Expanded>
+            12 > 2
+          </Expanded>
+        </Expression>
+        <OverallResults successes="1" failures="0" expectedFailures="0"/>
+      </Section>
+      <Section name="two" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+          <Original>
+            4u * i > str.size()
+          </Original>
+          <Expanded>
+            12 > 3
+          </Expanded>
+        </Expression>
         <OverallResults successes="1" failures="0" expectedFailures="0"/>
       </Section>
       <OverallResult success="true"/>
     </TestCase>
-    <TestCase name="Generators impl" tags="[impl]" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
-      <Section name="range" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
-        <Expression success="true" type="CHECK" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+    <TestCase name="Generators internals" tags="[generators][internals]" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+      <Section name="Single value" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+          <Original>
+            gen.get() == 123
+          </Original>
+          <Expanded>
+            123 == 123
+          </Expanded>
+        </Expression>
+        <Expression success="true" type="REQUIRE_FALSE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+          <Original>
+            !(gen.next())
+          </Original>
+          <Expanded>
+            !false
+          </Expanded>
+        </Expression>
+        <OverallResults successes="2" failures="0" expectedFailures="0"/>
+      </Section>
+      <Section name="Preset values" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+          <Original>
+            gen.get() == 1
+          </Original>
+          <Expanded>
+            1 == 1
+          </Expanded>
+        </Expression>
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+          <Original>
+            gen.next()
+          </Original>
+          <Expanded>
+            true
+          </Expanded>
+        </Expression>
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+          <Original>
+            gen.get() == 3
+          </Original>
+          <Expanded>
+            3 == 3
+          </Expanded>
+        </Expression>
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+          <Original>
+            gen.next()
+          </Original>
+          <Expanded>
+            true
+          </Expanded>
+        </Expression>
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+          <Original>
+            gen.get() == 5
+          </Original>
+          <Expanded>
+            5 == 5
+          </Expanded>
+        </Expression>
+        <Expression success="true" type="REQUIRE_FALSE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
           <Original>
-            gen.size() == 2
+            !(gen.next())
           </Original>
           <Expanded>
-            2 == 2
+            !false
           </Expanded>
         </Expression>
-        <Expression success="true" type="CHECK" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+        <OverallResults successes="6" failures="0" expectedFailures="0"/>
+      </Section>
+      <Section name="Generator combinator" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
           <Original>
-            gen[0] == 1
+            gen.get() == 1
           </Original>
           <Expanded>
             1 == 1
           </Expanded>
         </Expression>
-        <Expression success="true" type="CHECK" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
           <Original>
-            gen[1] == 2
+            gen.next()
           </Original>
           <Expanded>
-            2 == 2
+            true
           </Expanded>
         </Expression>
-        <OverallResults successes="3" failures="0" expectedFailures="0"/>
-      </Section>
-      <Section name="fixed values" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
-        <Expression success="true" type="CHECK" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
           <Original>
-            gen.size() == 4
+            gen.get() == 5
           </Original>
           <Expanded>
-            4 == 4
+            5 == 5
           </Expanded>
         </Expression>
-        <Expression success="true" type="CHECK" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
           <Original>
-            gen[0] == 3
+            gen.next()
           </Original>
           <Expanded>
-            3 == 3
+            true
           </Expanded>
         </Expression>
-        <Expression success="true" type="CHECK" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
           <Original>
-            gen[1] == 1
+            gen.get() == 2
           </Original>
           <Expanded>
-            1 == 1
+            2 == 2
+          </Expanded>
+        </Expression>
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+          <Original>
+            gen.next()
+          </Original>
+          <Expanded>
+            true
           </Expanded>
         </Expression>
-        <Expression success="true" type="CHECK" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
           <Original>
-            gen[2] == 4
+            gen.get() == 4
           </Original>
           <Expanded>
             4 == 4
           </Expanded>
         </Expression>
-        <Expression success="true" type="CHECK" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
           <Original>
-            gen[3] == 1
+            gen.next()
           </Original>
           <Expanded>
-            1 == 1
+            true
           </Expanded>
         </Expression>
-        <OverallResults successes="5" failures="0" expectedFailures="0"/>
-      </Section>
-      <Section name="combined" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
-        <Expression success="true" type="CHECK" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
           <Original>
-            gen.size() == 4
+            gen.get() == 0
           </Original>
           <Expanded>
-            4 == 4
+            0 == 0
           </Expanded>
         </Expression>
-        <Expression success="true" type="CHECK" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+        <Expression success="true" type="REQUIRE_FALSE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
           <Original>
-            gen[0] == 1
+            !(gen.next())
           </Original>
           <Expanded>
-            1 == 1
+            !false
           </Expanded>
         </Expression>
-        <Expression success="true" type="CHECK" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+        <OverallResults successes="10" failures="0" expectedFailures="0"/>
+      </Section>
+      <Section name="Explicitly typed generator sequence" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
           <Original>
-            gen[1] == 2
+            gen.get().size() == 2
           </Original>
           <Expanded>
             2 == 2
           </Expanded>
         </Expression>
-        <Expression success="true" type="CHECK" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
           <Original>
-            gen[2] == 9
+            gen.get() == "aa"
           </Original>
           <Expanded>
-            9 == 9
+            "aa" == "aa"
           </Expanded>
         </Expression>
-        <Expression success="true" type="CHECK" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
           <Original>
-            gen[3] == 7
+            gen.next()
           </Original>
           <Expanded>
-            7 == 7
+            true
           </Expanded>
         </Expression>
-        <OverallResults successes="5" failures="0" expectedFailures="0"/>
-      </Section>
-      <Section name="values" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
-        <Expression success="true" type="CHECK" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
           <Original>
-            gen.size() == 2
+            gen.get() == "bb"
           </Original>
           <Expanded>
-            2 == 2
+            "bb" == "bb"
           </Expanded>
         </Expression>
-        <Expression success="true" type="CHECK" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
           <Original>
-            gen[0] == 3
+            gen.next()
           </Original>
           <Expanded>
-            3 == 3
+            true
           </Expanded>
         </Expression>
-        <Expression success="true" type="CHECK" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
           <Original>
-            gen[1] == 1
+            gen.get() == "cc"
           </Original>
           <Expanded>
-            1 == 1
+            "cc" == "cc"
           </Expanded>
         </Expression>
-        <OverallResults successes="3" failures="0" expectedFailures="0"/>
+        <Expression success="true" type="REQUIRE_FALSE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+          <Original>
+            !(gen.next())
+          </Original>
+          <Expanded>
+            !false
+          </Expanded>
+        </Expression>
+        <OverallResults successes="7" failures="0" expectedFailures="0"/>
       </Section>
-      <Section name="values2" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
-        <Expression success="true" type="CHECK" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+      <Section name="Filter generator" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
           <Original>
-            gen.size() == 2
+            gen.get() == 1
           </Original>
           <Expanded>
-            2 == 2
+            1 == 1
+          </Expanded>
+        </Expression>
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+          <Original>
+            gen.next()
+          </Original>
+          <Expanded>
+            true
           </Expanded>
         </Expression>
-        <Expression success="true" type="CHECK" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
           <Original>
-            gen[0] == 3
+            gen.get() == 3
           </Original>
           <Expanded>
             3 == 3
           </Expanded>
         </Expression>
-        <Expression success="true" type="CHECK" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+        <Expression success="true" type="REQUIRE_FALSE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
           <Original>
-            gen[1] == 1
+            !(gen.next())
           </Original>
           <Expanded>
-            1 == 1
+            !false
           </Expanded>
         </Expression>
-        <OverallResults successes="3" failures="0" expectedFailures="0"/>
+        <Expression success="true" type="REQUIRE_THROWS_AS" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+          <Original>
+            filter([] (int) { return false; }, value(1)), Catch::GeneratorException
+          </Original>
+          <Expanded>
+            filter([] (int) { return false; }, value(1)), Catch::GeneratorException
+          </Expanded>
+        </Expression>
+        <OverallResults successes="5" failures="0" expectedFailures="0"/>
+      </Section>
+      <Section name="Take generator" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+        <Section name="Take less" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+          <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+            <Original>
+              gen.get() == 1
+            </Original>
+            <Expanded>
+              1 == 1
+            </Expanded>
+          </Expression>
+          <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+            <Original>
+              gen.next()
+            </Original>
+            <Expanded>
+              true
+            </Expanded>
+          </Expression>
+          <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+            <Original>
+              gen.get() == 2
+            </Original>
+            <Expanded>
+              2 == 2
+            </Expanded>
+          </Expression>
+          <Expression success="true" type="REQUIRE_FALSE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+            <Original>
+              !(gen.next())
+            </Original>
+            <Expanded>
+              !false
+            </Expanded>
+          </Expression>
+          <OverallResults successes="4" failures="0" expectedFailures="0"/>
+        </Section>
+        <OverallResults successes="4" failures="0" expectedFailures="0"/>
+      </Section>
+      <Section name="Take generator" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+        <Section name="Take more" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+          <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+            <Original>
+              gen.get() == 1
+            </Original>
+            <Expanded>
+              1 == 1
+            </Expanded>
+          </Expression>
+          <Expression success="true" type="REQUIRE_FALSE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+            <Original>
+              !(gen.next())
+            </Original>
+            <Expanded>
+              !false
+            </Expanded>
+          </Expression>
+          <OverallResults successes="2" failures="0" expectedFailures="0"/>
+        </Section>
+        <OverallResults successes="2" failures="0" expectedFailures="0"/>
       </Section>
-      <Section name="type erasure" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
-        <Expression success="true" type="CHECK" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+      <Section name="Map" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
           <Original>
-            base->size() == 4
+            gen.get() == 2.0
           </Original>
           <Expanded>
-            4 == 4
+            2.0 == 2.0
+          </Expanded>
+        </Expression>
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+          <Original>
+            gen.next()
+          </Original>
+          <Expanded>
+            true
           </Expanded>
         </Expression>
         <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
           <Original>
-            typed
+            gen.get() == 4.0
           </Original>
           <Expanded>
-            0x<hex digits>
+            4.0 == 4.0
           </Expanded>
         </Expression>
-        <Expression success="true" type="CHECK" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
           <Original>
-            typed->size() == 4
+            gen.next()
           </Original>
           <Expanded>
-            4 == 4
+            true
           </Expanded>
         </Expression>
-        <Expression success="true" type="CHECK" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+        <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
           <Original>
-            (*typed)[0] == 7
+            gen.get() == 6.0
           </Original>
           <Expanded>
-            7 == 7
+            6.0 == 6.0
           </Expanded>
         </Expression>
-        <Expression success="true" type="CHECK" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+        <Expression success="true" type="REQUIRE_FALSE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
           <Original>
-            (*typed)[3] == 11
+            !(gen.next())
           </Original>
           <Expanded>
-            11 == 11
+            !false
           </Expanded>
         </Expression>
-        <OverallResults successes="5" failures="0" expectedFailures="0"/>
+        <OverallResults successes="6" failures="0" expectedFailures="0"/>
+      </Section>
+      <Section name="Repeat" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+        <Section name="Singular repeat" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+          <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+            <Original>
+              gen.get() == 3
+            </Original>
+            <Expanded>
+              3 == 3
+            </Expanded>
+          </Expression>
+          <Expression success="true" type="REQUIRE_FALSE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+            <Original>
+              !(gen.next())
+            </Original>
+            <Expanded>
+              !false
+            </Expanded>
+          </Expression>
+          <OverallResults successes="2" failures="0" expectedFailures="0"/>
+        </Section>
+        <OverallResults successes="2" failures="0" expectedFailures="0"/>
+      </Section>
+      <Section name="Repeat" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+        <Section name="Actual repeat" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+          <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+            <Original>
+              gen.get() == 1
+            </Original>
+            <Expanded>
+              1 == 1
+            </Expanded>
+          </Expression>
+          <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+            <Original>
+              gen.next()
+            </Original>
+            <Expanded>
+              true
+            </Expanded>
+          </Expression>
+          <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+            <Original>
+              gen.get() == 2
+            </Original>
+            <Expanded>
+              2 == 2
+            </Expanded>
+          </Expression>
+          <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+            <Original>
+              gen.next()
+            </Original>
+            <Expanded>
+              true
+            </Expanded>
+          </Expression>
+          <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+            <Original>
+              gen.get() == 3
+            </Original>
+            <Expanded>
+              3 == 3
+            </Expanded>
+          </Expression>
+          <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+            <Original>
+              gen.next()
+            </Original>
+            <Expanded>
+              true
+            </Expanded>
+          </Expression>
+          <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+            <Original>
+              gen.get() == 1
+            </Original>
+            <Expanded>
+              1 == 1
+            </Expanded>
+          </Expression>
+          <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+            <Original>
+              gen.next()
+            </Original>
+            <Expanded>
+              true
+            </Expanded>
+          </Expression>
+          <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+            <Original>
+              gen.get() == 2
+            </Original>
+            <Expanded>
+              2 == 2
+            </Expanded>
+          </Expression>
+          <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+            <Original>
+              gen.next()
+            </Original>
+            <Expanded>
+              true
+            </Expanded>
+          </Expression>
+          <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+            <Original>
+              gen.get() == 3
+            </Original>
+            <Expanded>
+              3 == 3
+            </Expanded>
+          </Expression>
+          <Expression success="true" type="REQUIRE_FALSE" filename="projects/<exe-name>/IntrospectiveTests/GeneratorsImpl.tests.cpp" >
+            <Original>
+              !(gen.next())
+            </Original>
+            <Expanded>
+              !false
+            </Expanded>
+          </Expression>
+          <OverallResults successes="12" failures="0" expectedFailures="0"/>
+        </Section>
+        <OverallResults successes="12" failures="0" expectedFailures="0"/>
       </Section>
       <OverallResult success="true"/>
     </TestCase>
@@ -11180,7 +11563,7 @@ loose text artifact
       </Expression>
       <OverallResult success="true"/>
     </TestCase>
-    <TestCase name="strlen3" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+    <TestCase name="strlen3" tags="[generators]" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
       <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
         <Original>
           data.str.size() == data.len
@@ -11215,6 +11598,41 @@ loose text artifact
       </Expression>
       <OverallResult success="true"/>
     </TestCase>
+    <TestCase name="tables" tags="[generators]" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+      <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+        <Original>
+          strlen(std::get&lt;0>(data)) == static_cast&lt;size_t>(std::get&lt;1>(data))
+        </Original>
+        <Expanded>
+          5 == 5
+        </Expanded>
+      </Expression>
+      <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+        <Original>
+          strlen(std::get&lt;0>(data)) == static_cast&lt;size_t>(std::get&lt;1>(data))
+        </Original>
+        <Expanded>
+          6 == 6
+        </Expanded>
+      </Expression>
+      <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+        <Original>
+          strlen(std::get&lt;0>(data)) == static_cast&lt;size_t>(std::get&lt;1>(data))
+        </Original>
+        <Expanded>
+          5 == 5
+        </Expanded>
+      </Expression>
+      <Expression success="true" type="REQUIRE" filename="projects/<exe-name>/UsageTests/Generators.tests.cpp" >
+        <Original>
+          strlen(std::get&lt;0>(data)) == static_cast&lt;size_t>(std::get&lt;1>(data))
+        </Original>
+        <Expanded>
+          6 == 6
+        </Expanded>
+      </Expression>
+      <OverallResult success="true"/>
+    </TestCase>
     <TestCase name="thrown std::strings are translated" tags="[!throws][.][failing]" filename="projects/<exe-name>/UsageTests/Exception.tests.cpp" >
       <Exception filename="projects/<exe-name>/UsageTests/Exception.tests.cpp" >
         Why would you throw a std::string?
@@ -11733,7 +12151,7 @@ loose text artifact
       </Section>
       <OverallResult success="true"/>
     </TestCase>
-    <OverallResults successes="1126" failures="130" expectedFailures="21"/>
+    <OverallResults successes="1161" failures="130" expectedFailures="21"/>
   </Group>
-  <OverallResults successes="1126" failures="129" expectedFailures="21"/>
+  <OverallResults successes="1161" failures="129" expectedFailures="21"/>
 </Catch>
diff --git a/projects/SelfTest/IntrospectiveTests/GeneratorsImpl.tests.cpp b/projects/SelfTest/IntrospectiveTests/GeneratorsImpl.tests.cpp
index b3074b2e17..0f581947bb 100644
--- a/projects/SelfTest/IntrospectiveTests/GeneratorsImpl.tests.cpp
+++ b/projects/SelfTest/IntrospectiveTests/GeneratorsImpl.tests.cpp
@@ -1,93 +1,103 @@
 #include "catch.hpp"
 
-// Tests of generartor implementation details
-
-TEST_CASE("Generators impl", "[impl]") {
+// Tests of generator implementation details
+TEST_CASE("Generators internals", "[generators][internals]") {
     using namespace Catch::Generators;
 
-    SECTION( "range" ) {
-        auto gen = range(1,3);
-
-        CHECK( gen.size() == 2 );
-
-        CHECK( gen[0] == 1 );
-        CHECK( gen[1] == 2 );
+    SECTION("Single value") {
+        auto gen = value(123);
+        REQUIRE(gen.get() == 123);
+        REQUIRE_FALSE(gen.next());
     }
-    SECTION( "fixed values" ) {
-        auto gen = values( { 3, 1, 4, 1 } );
-
-        CHECK( gen.size() == 4 );
-        CHECK( gen[0] == 3 );
-        CHECK( gen[1] == 1 );
-        CHECK( gen[2] == 4 );
-        CHECK( gen[3] == 1 );
-    }
-    SECTION( "combined" ) {
-        auto gen = makeGenerators( range( 1, 3 ), values( { 9, 7 } ) );
-
-        CHECK( gen.size() == 4 );
-        CHECK( gen[0] == 1 );
-        CHECK( gen[1] == 2 );
-        CHECK( gen[2] == 9 );
-        CHECK( gen[3] == 7 );
+    SECTION("Preset values") {
+        auto gen = values({ 1, 3, 5 });
+        REQUIRE(gen.get() == 1);
+        REQUIRE(gen.next());
+        REQUIRE(gen.get() == 3);
+        REQUIRE(gen.next());
+        REQUIRE(gen.get() == 5);
+        REQUIRE_FALSE(gen.next());
     }
-
-    SECTION( "values" ) {
-        auto gen = makeGenerators( 3, 1 );
-
-        CHECK( gen.size() == 2 );
-        CHECK( gen[0] == 3 );
-        CHECK( gen[1] == 1 );
+    SECTION("Generator combinator") {
+        auto gen = makeGenerators(1, 5, values({ 2, 4 }), 0);
+        REQUIRE(gen.get() == 1);
+        REQUIRE(gen.next());
+        REQUIRE(gen.get() == 5);
+        REQUIRE(gen.next());
+        REQUIRE(gen.get() == 2);
+        REQUIRE(gen.next());
+        REQUIRE(gen.get() == 4);
+        REQUIRE(gen.next());
+        REQUIRE(gen.get() == 0);
+        REQUIRE_FALSE(gen.next());
     }
-    SECTION( "values2" ) {
-        auto gen = makeGenerators( 3, 1 );
-
-        CHECK( gen.size() == 2 );
-        CHECK( gen[0] == 3 );
-        CHECK( gen[1] == 1 );
+    SECTION("Explicitly typed generator sequence") {
+        auto gen = makeGenerators(as<std::string>{}, "aa", "bb", "cc");
+        // This just checks that the type is std::string:
+        REQUIRE(gen.get().size() == 2);
+        // Iterate over the generator
+        REQUIRE(gen.get() == "aa");
+        REQUIRE(gen.next());
+        REQUIRE(gen.get() == "bb");
+        REQUIRE(gen.next());
+        REQUIRE(gen.get() == "cc");
+        REQUIRE_FALSE(gen.next());
     }
-
-
-    SECTION( "type erasure" ) {
-        auto gen = makeGenerators( range( 7, 10 ), 11 );
-
-        // Make type erased version
-        auto dynCopy = pf::make_unique<Generators<int>>( std::move( gen ) );
-        std::unique_ptr<GeneratorBase const> base = std::move( dynCopy );
-
-        // Only thing we can do is ask for the size
-        CHECK( base->size() == 4 );
-
-        // Restore typed version
-        auto typed = dynamic_cast<Generators<int> const*>( base.get() );
-        REQUIRE( typed );
-        CHECK( typed->size() == 4 );
-        CHECK( (*typed)[0] == 7 );
-        CHECK( (*typed)[3] == 11 );
+    SECTION("Filter generator") {
+        // Normal usage
+        auto gen = filter([] (int i) { return i != 2; }, values({ 2, 1, 2, 3, 2, 2 }));
+        REQUIRE(gen.get() == 1);
+        REQUIRE(gen.next());
+        REQUIRE(gen.get() == 3);
+        REQUIRE_FALSE(gen.next());
+
+        // Completely filtered-out generator should throw on construction
+        REQUIRE_THROWS_AS(filter([] (int) { return false; }, value(1)), Catch::GeneratorException);
     }
-}
-
-TEST_CASE("Generators impl - random", "[approvals]") {
-    using namespace Catch::Generators;
-
-    SECTION( "random range" ) {
-        auto gen = random( 3, 9 );
-
-        CHECK( gen.size() == 6 );
-        for( size_t i = 0; i < 6; ++i ) {
-            CHECK( gen[i] >= 3 );
-            CHECK( gen[i] <= 8 );
-            if( i > 0 )
-                CHECK( gen[i] != gen[i-1] );
+    SECTION("Take generator") {
+        SECTION("Take less") {
+            auto gen = take(2, values({ 1, 2, 3 }));
+            REQUIRE(gen.get() == 1);
+            REQUIRE(gen.next());
+            REQUIRE(gen.get() == 2);
+            REQUIRE_FALSE(gen.next());
+        }
+        SECTION("Take more") {
+            auto gen = take(2, value(1));
+            REQUIRE(gen.get() == 1);
+            REQUIRE_FALSE(gen.next());
         }
     }
-    SECTION( "random selection" ) {
-        auto gen = random<int>( 10 );
-
-        CHECK( gen.size() == 10 );
-        for( size_t i = 0; i < 10; ++i ) {
-            if( i > 0 )
-                CHECK( gen[i] != gen[i-1] );
+    SECTION("Map") {
+        auto gen = map<double>([] (int i) {return 2.0 * i; }, values({ 1, 2, 3 }));
+        REQUIRE(gen.get() == 2.0);
+        REQUIRE(gen.next());
+        REQUIRE(gen.get() == 4.0);
+        REQUIRE(gen.next());
+        REQUIRE(gen.get() == 6.0);
+        REQUIRE_FALSE(gen.next());
+    }
+    SECTION("Repeat") {
+        SECTION("Singular repeat") {
+            auto gen = repeat(1, value(3));
+            REQUIRE(gen.get() == 3);
+            REQUIRE_FALSE(gen.next());
+        }
+        SECTION("Actual repeat") {
+            auto gen = repeat(2, values({ 1, 2, 3 }));
+            REQUIRE(gen.get() == 1);
+            REQUIRE(gen.next());
+            REQUIRE(gen.get() == 2);
+            REQUIRE(gen.next());
+            REQUIRE(gen.get() == 3);
+            REQUIRE(gen.next());
+            REQUIRE(gen.get() == 1);
+            REQUIRE(gen.next());
+            REQUIRE(gen.get() == 2);
+            REQUIRE(gen.next());
+            REQUIRE(gen.get() == 3);
+            REQUIRE_FALSE(gen.next());
         }
     }
+
 }
diff --git a/projects/SelfTest/UsageTests/Generators.tests.cpp b/projects/SelfTest/UsageTests/Generators.tests.cpp
index 9242174a8a..0110b4420c 100644
--- a/projects/SelfTest/UsageTests/Generators.tests.cpp
+++ b/projects/SelfTest/UsageTests/Generators.tests.cpp
@@ -1,75 +1,63 @@
 #include "catch.hpp"
 
-// Examples of usage of Generators
+#include <cstring>
 
-// This test doesn't do much - it just shows how you can have several generators, of different
-// types (ie `i` and `j` are different types), can be sequenced using `,` and
-// can be expressed as named generators (like range) or as individual values.
-// Generators can be mixed with SECTIONs.
-// At time of writing the generated values are not automatically reported as part of the test
-// name or associated values - so we explicitly CAPTURE then (run this with `-s` to see them).
-// We could also incorporate them into the section names using DYNAMIC_SECTION. See the BDD
-// example later for more information.
-TEST_CASE("Generators") {
 
-    auto i = GENERATE( as<std::string>(), "a", "b", "c" );
-
-    SECTION( "one" ) {
-        auto j = GENERATE( range( 8, 11 ), 2 );
-
-        CAPTURE( i, j );
-        SUCCEED();
+// Generators and sections can be nested freely
+TEST_CASE("Generators -- simple", "[generators]") {
+    auto i = GENERATE(1, 2, 3);
+    SECTION("one") {
+        auto j = GENERATE(values({ -3, -2, -1 }));
+        REQUIRE(j < i);
     }
-    SECTION( "two" ) {
-        auto j = GENERATE( 3.141, 1.379 );
-        CAPTURE( i, j );
-        SUCCEED();
+
+    SECTION("two") {
+        // You can also explicitly set type for generators via Catch::Generators::as
+        auto str = GENERATE(as<std::string>{}, "a", "bb", "ccc");
+        REQUIRE(4u * i > str.size());
     }
 }
 
-// This one generates the cross-product of two ranges.
-// It's mostly here to demonstrate the performance which, at time of writing,
-// leaves a lot to be desired.
-TEST_CASE( "100x100 ints", "[.][approvals]" ) {
-    auto x = GENERATE( range( 0,100 ) );
-    auto y = GENERATE( range( 200,300 ) );
-
-    CHECK( x < y );
+// You can create a cartesian-product of generators by creating multiple ones
+TEST_CASE("3x3x3 ints", "[generators]") {
+    auto x = GENERATE(1, 2, 3);
+    auto y = GENERATE(4, 5, 6);
+    auto z = GENERATE(7, 8, 9);
+    // These assertions will be run 27 times (3x3x3)
+    CHECK(x < y);
+    CHECK(y < z);
+    REQUIRE(x < z);
 }
 
-// smaller version
-TEST_CASE( "10x10 ints" ) {
-    auto x = GENERATE( range( 1,11 ) );
-    auto y = GENERATE( range( 101, 111 ) );
-
-    CHECK( x < y );
+// You can also create data tuples
+TEST_CASE("tables", "[generators]") {
+    // Note that this will not compile with libstdc++ older than libstdc++6
+    // See https://stackoverflow.com/questions/12436586/tuple-vector-and-initializer-list
+    // for possible workarounds
+    //    auto data = GENERATE(table<char const*, int>({
+    //        {"first", 5},
+    //        {"second", 6},
+    //        {"third", 5},
+    //        {"etc...", 6}
+    //    }));
+
+    // Workaround for the libstdc++ bug mentioned above
+    using tuple_type = std::tuple<char const*, int>;
+    auto data = GENERATE(table<char const*, int>({
+        tuple_type{"first", 5},
+        tuple_type{"second", 6},
+        tuple_type{"third", 5},
+        tuple_type{"etc...", 6}
+    }));
+
+    REQUIRE(strlen(std::get<0>(data)) == static_cast<size_t>(std::get<1>(data)));
 }
 
-// Some of the following tests use structured bindings for convenience and so are
-// conditionally compiled using the de-facto (and soon to be formally) standard
-// feature macros
 
 #ifdef __cpp_structured_bindings
 
-// One way to do pairs of values (actual/ expected?)
-// For a simple case like this I'd recommend writing out a series of REQUIREs
-// but it demonstrates a possible usage.
-// Spelling out the pair like this is a bit verbose, so read on for better examples
-// - the use of structured bindings here is an optional convenience
-TEST_CASE( "strlen", "[approvals]" ) {
-    auto [test_input, expected] = GENERATE( values<std::pair<std::string_view, size_t>>({
-            {"one", 3},
-            {"two", 3},
-            {"three", 5},
-            {"four", 4}
-        }));
-
-    REQUIRE( test_input.size() == expected );
-}
-
-// A nicer way to do pairs (or more) of values - using the table generator.
-// Note, you must specify the types up-front.
-TEST_CASE( "strlen2", "[approvals]" ) {
+// Structured bindings make the table utility much nicer to use
+TEST_CASE( "strlen2", "[approvals][generators]" ) {
     auto [test_input, expected] = GENERATE( table<std::string, size_t>({
             {"one", 3},
             {"two", 3},
@@ -81,11 +69,11 @@ TEST_CASE( "strlen2", "[approvals]" ) {
 }
 #endif
 
-// An alternate way of doing data tables without structure bindings
-// - I'd prefer to have the Data class within the test case but gcc 4.x doesn't seem to like it
+
+// An alternate way of doing data tables without structured bindings
 struct Data { std::string str; size_t len; };
 
-TEST_CASE( "strlen3" ) {
+TEST_CASE( "strlen3", "[generators]" ) {
     auto data = GENERATE( values<Data>({
             {"one", 3},
             {"two", 3},
@@ -96,15 +84,7 @@ TEST_CASE( "strlen3" ) {
     REQUIRE( data.str.size() == data.len );
 }
 
-// A nod towards property-based testing - generate a random selection of numbers
-// in a range and assert on global properties those numbers.
-static auto square( int i ) -> int { return i*i; }
 
-TEST_CASE( "Random numbers in a range", "[.][approvals]" ) {
-    auto x = GENERATE( random( -10000, 10000 ) );
-    CAPTURE( x );
-    REQUIRE( square(x) >= 0 );
-}
 
 #ifdef __cpp_structured_bindings
 
@@ -118,7 +98,7 @@ TEST_CASE( "Random numbers in a range", "[.][approvals]" ) {
 
 static auto eatCucumbers( int start, int eat ) -> int { return start-eat; }
 
-SCENARIO("Eating cucumbers", "[approvals]") {
+SCENARIO("Eating cucumbers", "[generators][approvals]") {
 
     auto [start, eat, left] = GENERATE( table<int,int,int> ({
             { 12, 5, 7 },
@@ -132,3 +112,36 @@ SCENARIO("Eating cucumbers", "[approvals]") {
     }
 }
 #endif
+
+// There are also some generic generator manipulators
+TEST_CASE("Generators -- adapters", "[generators]") {
+    // TODO: This won't work yet, introduce GENERATE_VAR?
+    //auto numbers = Catch::Generators::values({ 1, 2, 3, 4, 5, 6 });
+    SECTION("Filtering by predicate") {
+        // This filters out all odd (false) numbers, giving [2, 4, 6]
+        auto i = GENERATE(filter([] (int val) { return val % 2 == 0; }, values({ 1, 2, 3, 4, 5, 6 })));
+        REQUIRE(i % 2 == 0);
+    }
+    SECTION("Shortening a range") {
+        // This takes the first 3 elements from the values, giving back [1, 2, 3]
+        auto i = GENERATE(take(3, values({ 1, 2, 3, 4, 5, 6 })));
+        REQUIRE(i < 4);
+    }
+    SECTION("Transforming elements") {
+        SECTION("Same type") {
+            // This doubles values [1, 2, 3] into [2, 4, 6]
+            auto i = GENERATE(map([] (int val) { return val * 2; }, values({ 1, 2, 3 })));
+            REQUIRE(i % 2 == 0);
+        }
+        SECTION("Different type") {
+            // This takes a generator that returns ints and maps them into strings
+            auto i = GENERATE(map<std::string>([] (int val) { return std::to_string(val); }, values({ 1, 2, 3 })));
+            REQUIRE(i.size() == 1);
+        }
+    }
+    SECTION("Repeating a generator") {
+        // This will return values [1, 2, 3, 1, 2, 3]
+        auto j = GENERATE(repeat(2, values({ 1, 2, 3 })));
+        REQUIRE(j > 0);
+    }
+}