From cb89213cfeda8bd2083df23781f55eb1a7429929 Mon Sep 17 00:00:00 2001
From: HansBhatia <78050086+HansBhatia@users.noreply.github.com>
Date: Tue, 27 Jun 2023 11:54:31 -0400
Subject: [PATCH] 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 <msaug@protonmail.com>
---
 listings/ch00-introduction/events/.gitignore  |  1 +
 listings/ch00-introduction/events/Scarb.toml  |  8 +++++++
 .../events/src/counter.cairo                  | 23 +++++++++++++++++++
 .../ch00-introduction/events/src/lib.cairo    |  1 +
 src/SUMMARY.md                                |  1 +
 src/ch00-10-events.md                         |  9 ++++++++
 6 files changed, 43 insertions(+)
 create mode 100644 listings/ch00-introduction/events/.gitignore
 create mode 100644 listings/ch00-introduction/events/Scarb.toml
 create mode 100644 listings/ch00-introduction/events/src/counter.cairo
 create mode 100644 listings/ch00-introduction/events/src/lib.cairo
 create mode 100644 src/ch00-10-events.md

diff --git a/listings/ch00-introduction/events/.gitignore b/listings/ch00-introduction/events/.gitignore
new file mode 100644
index 00000000..eb5a316c
--- /dev/null
+++ b/listings/ch00-introduction/events/.gitignore
@@ -0,0 +1 @@
+target
diff --git a/listings/ch00-introduction/events/Scarb.toml b/listings/ch00-introduction/events/Scarb.toml
new file mode 100644
index 00000000..63071abe
--- /dev/null
+++ b/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]]
\ No newline at end of file
diff --git a/listings/ch00-introduction/events/src/counter.cairo b/listings/ch00-introduction/events/src/counter.cairo
new file mode 100644
index 00000000..3c23ad23
--- /dev/null
+++ b/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);
+    }
+}
diff --git a/listings/ch00-introduction/events/src/lib.cairo b/listings/ch00-introduction/events/src/lib.cairo
new file mode 100644
index 00000000..f5271637
--- /dev/null
+++ b/listings/ch00-introduction/events/src/lib.cairo
@@ -0,0 +1 @@
+mod counter;
diff --git a/src/SUMMARY.md b/src/SUMMARY.md
index cdaba3fb..113a2061 100644
--- a/src/SUMMARY.md
+++ b/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)
diff --git a/src/ch00-10-events.md b/src/ch00-10-events.md
new file mode 100644
index 00000000..417f36e1
--- /dev/null
+++ b/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}}
+```