From 91c373e8cb9cacad8af0e7c6b6d43bbadb0a477d Mon Sep 17 00:00:00 2001
From: chachaleo <charlotte.leo@hotmail.com>
Date: Mon, 9 Oct 2023 14:37:43 +0700
Subject: [PATCH] addition function nullable is_null

---
 corelib/src/nullable.cairo | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/corelib/src/nullable.cairo b/corelib/src/nullable.cairo
index a7a35fd222d..8fc77416b61 100644
--- a/corelib/src/nullable.cairo
+++ b/corelib/src/nullable.cairo
@@ -17,6 +17,7 @@ extern fn match_nullable<T>(value: Nullable<T>) -> FromNullableResult<T> nopanic
 trait NullableTrait<T> {
     fn deref(self: Nullable<T>) -> T;
     fn new(value: T) -> Nullable<T>;
+    fn is_null<+Drop<T>>(self: Nullable<T>) -> bool;
 }
 
 impl NullableImpl<T> of NullableTrait<T> {
@@ -29,6 +30,12 @@ impl NullableImpl<T> of NullableTrait<T> {
     fn new(value: T) -> Nullable<T> {
         nullable_from_box(BoxTrait::new(value))
     }
+    fn is_null<+Drop<T>>(self: Nullable<T>) -> bool {
+        match match_nullable(self) {
+            FromNullableResult::Null => true,
+            FromNullableResult::NotNull(_) => false,
+        }
+    }
 }
 
 impl NullableDefault<T> of Default<Nullable<T>> {