Feat events (#46)

* feat(if-else): add if-else access control

* fix(if_else): CI issue

* fix: add pr review changes

* fix: pr review comments

* docs: add documentation to contract

* docs(src): add readme file

* docs(src): add contract desc

* fix: terminology & add to SUMMARY

* feat(events): add events

* chore: add to summary

* chore: add type

* fix: pr review changes

---------

Co-authored-by: msaug <[email protected]>

listings/ch00-introduction/events/.gitignore

@@ -0,0 +1 @@
+target

listings/ch00-introduction/events/Scarb.toml

@@ -0,0 +1,8 @@
+[package]
+name = "counter"
+version = "0.1.0"
+
+[dependencies]
+starknet = "1.1.0"
+
+[[target.starknet-contract]]

listings/ch00-introduction/events/src/counter.cairo

@@ -0,0 +1,23 @@
+#[contract]
+mod SimpleCounter {
+    struct Storage {
+        // Counter value
+        _counter: u256,
+    }
+
+    #[event]
+    // Increment event  -  emitted when the counter is incremented.
+    fn Increment(counterVal: u256) {}
+
+    #[constructor]
+    fn constructor() {}
+
+    #[external]
+    fn increment() {
+        let mut counter: u256 = _counter::read();
+        counter += 1;
+        _counter::write(counter);
+        // Emit event
+        Increment(counter);
+    }
+}

listings/ch00-introduction/events/src/lib.cairo

@@ -0,0 +1 @@
+mod counter;

src/SUMMARY.md

@@ -12,6 +12,7 @@ Summary
   - [Constructors](./ch00-07-constructor.md)
   - [Function Attributes](./ch00-08-function_attributes.md)
   - [If statements](./ch00-09-if_statements.md)
+  - [Events](./ch00-10-events.md)
 
 - [Applications](./ch01-00-applications.md)
   - [Upgradeable Contract](./ch01-01-upgradeable_contract.md)

src/ch00-10-events.md

@@ -0,0 +1,9 @@
+# Events
+
+An event is defined as function with the #[event] attribute. The parameters of the function correspond to data that will be emitted. An event is to be logged for easy and fast access to querying the data at a later time.
+
+Here's a simple example of a contract using events that emit an event each time a counter is incremented by the "increment" function:
+
+```rust
+{{#include ../listings/ch00-introduction/events/src/counter.cairo}}
+```