From 9481073b473cb78eab0fe088312c96880bb8d645 Mon Sep 17 00:00:00 2001
From: Keno Fischer <keno@alumni.harvard.edu>
Date: Tue, 28 Nov 2017 19:18:34 -0500
Subject: [PATCH] Improve enter macro

Check whether it's a simple function call before performing lowering (fixes #14),
and give a better error message when you try to enter something that's not a
function call (fixes #11).
---
 src/ASTInterpreter2.jl | 57 +++++++++++++++++++++++++++++++++---------
 test/misc.jl           |  6 +++++
 test/runtests.jl       |  3 ++-
 3 files changed, 53 insertions(+), 13 deletions(-)
 create mode 100644 test/misc.jl

diff --git a/src/ASTInterpreter2.jl b/src/ASTInterpreter2.jl
index a87c5606c34434..5341c421779274 100644
--- a/src/ASTInterpreter2.jl
+++ b/src/ASTInterpreter2.jl
@@ -437,19 +437,52 @@ end
 
 lower(mod, arg) = VERSION < v"0.7-" ? expand(arg) : Meta.lower(mod, arg)
 
+# This is a version of gen_call_with_extracted_types, except that is passes back the call expression
+# for further processing.
+function extract_args(__module__, ex0)
+    if isa(ex0, Expr)
+        kws = collect(filter(x->isexpr(x,:kw),ex0.args))
+        if !isempty(kws)
+            return Expr(:tuple,:(Core.kwfunc($(ex0.args[1]))),
+                Expr(:call,Base.vector_any,mapreduce(
+                x->[QuoteNode(x.args[1]),x.args[2]],vcat,kws)...),
+                map(x->isexpr(x, :parameters) ? QuoteNode(x) : x,
+                filter(x->!isexpr(x, :kw),ex0.args))...)
+        else
+            return Expr(:tuple,
+                map(x->isexpr(x,:parameters) ? QuoteNode(x) : x, ex0.args)...)
+        end
+    end
+    if isa(ex0, Expr) && ex0.head == :macrocall # Make @edit @time 1+2 edit the macro by using the types of the *expressions*
+        return error("Macros are not supported in @enter")
+    end
+    ex = lower(__module__, ex0)
+    exret = Expr(:none)
+    if !isa(ex, Expr)
+        return error("expression is not a function call or symbol")
+    elseif ex.head == :call
+        return Expr(:tuple,
+                map(x->isexpr(x,:parameters) ? QuoteNode(x) : x, ex.args)...)
+    elseif ex.head == :body
+        a1 = ex.args[1]
+        if isa(a1, Expr) && a1.head == :call
+            a11 = a1.args[1]
+            if a11 == :setindex!
+                return Expr(:tuple,
+                map(x->isexpr(x,:parameters) ? QuoteNode(x) : x, arg.args)...)
+            end
+        end
+    end
+    return error("expression is not a function call, "
+               * "or is too complex for @enter to analyze; "
+               * "break it down to simpler parts if possible")
+end
+
 function _make_stack(mod, arg)
-    arg = lower(mod, arg)
-    @assert isa(arg, Expr) && arg.head == :call
-    kws = collect(filter(x->isexpr(x,:kw),arg.args))
-    if !isempty(kws)
-      args = Expr(:tuple,:(Core.kwfunc($(args[1]))),
-        Expr(:call,Base.vector_any,mapreduce(
-          x->[QuoteNode(x.args[1]),x.args[2]],vcat,kws)...),
-        map(x->isexpr(x, :parameters) ? QuoteNode(x) : x,
-          filter(x->!isexpr(x, :kw),arg.args))...)
-    else
-      args = Expr(:tuple,
-        map(x->isexpr(x,:parameters) ? QuoteNode(x) : x, arg.args)...)
+    args = try
+        extract_args(mod, arg)
+    catch e
+        return :(throw($e))
     end
     quote
         theargs = $(esc(args))
diff --git a/test/misc.jl b/test/misc.jl
new file mode 100644
index 00000000000000..031e616963a470
--- /dev/null
+++ b/test/misc.jl
@@ -0,0 +1,6 @@
+# Issue #14
+stack = @make_stack map(x->2x, 1:10)
+state = dummy_state(stack)
+execute_command(state, state.stack[1], Val{:finish}(), "finish")
+@test isempty(state.stack)
+@test state.overall_result == 2 .* [1:10...]
diff --git a/test/runtests.jl b/test/runtests.jl
index 9f030204f3e2c4..286fa072ffc4eb 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -4,4 +4,5 @@ using Base.Test
 include("evaling.jl")
 include("stepping.jl")
 include("interpret.jl")
-include("ui.jl")
\ No newline at end of file
+include("ui.jl")
+include("misc.jl")
\ No newline at end of file