From 4cf700bcfe157ebc82cdf7321a16959b7a4add57 Mon Sep 17 00:00:00 2001
From: jfecher <jake@aztecprotocol.com>
Date: Fri, 15 Mar 2024 08:40:43 -0500
Subject: [PATCH] feat: Add more impls on Option (#4549)

# Description

## Problem\*

Resolves

## Summary\*

Adds more trait implementations on the Option type.

## Additional Context

This PR depends on https://github.com/noir-lang/noir/pull/4470 to be
merged first since it requires `bool: Hash`

## Documentation\*

Check one:
- [ ] No documentation needed.
- [ ] Documentation included in this PR.
- [x] **[Exceptional Case]** Documentation to be submitted in a separate
PR.
- Once both this and https://github.com/noir-lang/noir/pull/4470 are
merged I think I'll add all the new impls to the docs at once.

# PR Checklist\*

- [x] I have tested the changes locally.
- [x] I have formatted the changes with [Prettier](https://prettier.io/)
and/or `cargo fmt` on default settings.
---
 noir_stdlib/src/option.nr | 52 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)

diff --git a/noir_stdlib/src/option.nr b/noir_stdlib/src/option.nr
index 1c32f758af..c94a1cf836 100644
--- a/noir_stdlib/src/option.nr
+++ b/noir_stdlib/src/option.nr
@@ -1,3 +1,7 @@
+use crate::hash::{Hash, Hasher};
+use crate::cmp::{Ordering, Ord, Eq};
+use crate::default::Default;
+
 struct Option<T> {
     _is_some: bool,
     _value: T,
@@ -152,3 +156,51 @@ impl<T> Option<T> {
         }
     }
 }
+
+impl<T> Default for Option<T> {
+    fn default() -> Self {
+        Option::none()
+    }
+}
+
+impl<T> Eq for Option<T> where T: Eq {
+    fn eq(self, other: Self) -> bool {
+        if self._is_some == other._is_some {
+            if self._is_some {
+                self._value == other._value
+            } else {
+                true
+            }
+        } else {
+            false
+        }
+    }
+}
+
+impl<T> Hash for Option<T> where T: Hash {
+    fn hash<H>(self, state: &mut H) where H: Hasher {
+        self._is_some.hash(state);
+        if self._is_some {
+            self._value.hash(state);
+        }
+    }
+}
+
+// For this impl we're declaring Option::none < Option::some
+impl<T> Ord for Option<T> where T: Ord {
+    fn cmp(self, other: Self) -> Ordering {
+        if self._is_some {
+            if other._is_some {
+                self._value.cmp(other._value)
+            } else {
+                Ordering::greater()
+            }
+        } else {
+            if other._is_some {
+                Ordering::less()
+            } else {
+                Ordering::equal()
+            }
+        }
+    }
+}