From 21f822020fe5052c70cdc8e078173119805d51eb Mon Sep 17 00:00:00 2001
From: Stephen Chung <schungx@live.com>
Date: Wed, 27 Jul 2022 11:35:40 +0800
Subject: [PATCH] Add Scope::remove.

---
 CHANGELOG.md       |  1 +
 src/types/scope.rs | 35 +++++++++++++++++++++++++++++++++++
 2 files changed, 36 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index c81c5682..297abdb8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -45,6 +45,7 @@ Enhancements
 * `as_string` is added to BLOB's to convert it into a string by interpreting it as a UTF-8 byte stream.
 * `FnAccess::is_private`, `FnAccess::is_public`, `FnNamespace::is_module_namespace` and `FnNameSpace::is_global_namespace` are added for convenience.
 * `Iterator<Item=T>` type for functions metadata is simplified to `Iterator<T>`.
+* `Scope::remove` is added to remove a variable from a `Scope`, returning its value.
 
 
 Version 1.8.0
diff --git a/src/types/scope.rs b/src/types/scope.rs
index 41e40afe..5f92188d 100644
--- a/src/types/scope.rs
+++ b/src/types/scope.rs
@@ -550,6 +550,41 @@ impl Scope<'_> {
     pub fn get(&self, name: &str) -> Option<&Dynamic> {
         self.get_index(name).map(|(index, _)| &self.values[index])
     }
+    /// Remove the last entry in the [`Scope`] by the specified name and return its value.
+    ///
+    /// If the entry by the specified name is not found, [`None`] is returned.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// use rhai::Scope;
+    ///
+    /// let mut my_scope = Scope::new();
+    ///
+    /// my_scope.push("x", 123_i64);        // first 'x'
+    /// my_scope.push("x", 42_i64);         // second 'x', shadows first
+    ///
+    /// assert_eq!(my_scope.len(), 2);
+    ///
+    /// let value = my_scope.remove::<i64>("x").expect("x should exist");
+    ///
+    /// assert_eq!(value, 42);
+    ///
+    /// assert_eq!(my_scope.len(), 1);
+    ///
+    /// let value = my_scope.get_value::<i64>("x").expect("x should still exist");
+    ///
+    /// assert_eq!(value, 123);
+    /// ```
+    #[inline(always)]
+    #[must_use]
+    pub fn remove<T: Variant + Clone>(&mut self, name: &str) -> Option<T> {
+        self.get_index(name).and_then(|(index, _)| {
+            self.names.remove(index);
+            self.aliases.remove(index);
+            self.values.remove(index).try_cast()
+        })
+    }
     /// Get a mutable reference to an entry in the [`Scope`].
     ///
     /// If the entry by the specified name is not found, or if it is read-only,