Add Index + IndexMut operators for PackedArray

Author: Bromeon

godot-core/src/builtin/packed_array.rs

@@ -9,7 +9,7 @@ use godot_ffi as sys;
 
 use crate::builtin::meta::ToGodot;
 use crate::builtin::*;
-use std::fmt;
+use std::{fmt, ops};
 use sys::types::*;
 use sys::{ffi_methods, interface_fn, GodotFfi};
 
@@ -394,6 +394,24 @@ macro_rules! impl_packed_array {
             }
         }
 
+        impl ops::Index<usize> for $PackedArray {
+            type Output = $Element;
+
+            fn index(&self, index: usize) -> &Self::Output {
+                let ptr = self.ptr(index);
+                // SAFETY: `ptr` checked bounds.
+                unsafe { &*ptr }
+            }
+        }
+
+        impl ops::IndexMut<usize> for $PackedArray {
+            fn index_mut(&mut self, index: usize) -> &mut Self::Output {
+                let ptr = self.ptr_mut(index);
+                // SAFETY: `ptr` checked bounds.
+                unsafe { &mut *ptr }
+            }
+        }
+
         #[doc = concat!("Creates a `", stringify!($PackedArray), "` from the given Rust array.")]
         impl<const N: usize> From<&[$Element; N]> for $PackedArray {
             fn from(arr: &[$Element; N]) -> Self {

itest/rust/src/builtin_tests/containers/packed_array_test.rs

@@ -130,6 +130,31 @@ fn packed_array_as_mut_slice() {
     assert_eq!(empty.as_mut_slice(), &mut []);
 }
 
+#[itest]
+fn packed_array_index() {
+    let array = PackedByteArray::from(&[1, 2]);
+
+    assert_eq!(array[0], 1);
+    assert_eq!(array[1], 2);
+    expect_panic("Array index 2 out of bounds: length is 2", || {
+        let _ = array[2];
+    });
+
+    let mut array = PackedStringArray::new();
+    expect_panic("Array index 0 out of bounds: length is 0", || {
+        let _ = array[0];
+    });
+
+    array.push("first".into());
+    array.push("second".into());
+
+    assert_eq!(array[0], "first".into());
+    assert_eq!(array[1], "second".into());
+
+    array[0] = "begin".into();
+    assert_eq!(array[0], "begin".into());
+}
+
 #[itest]
 fn packed_array_get() {
     let array = PackedByteArray::from(&[1, 2]);