Merge pull request #1388 from lilizoey/feature/rename-var

Support `rename` for `#[var]`

Author: Bromeon

godot-macros/src/class/data_models/field_var.rs

@@ -18,6 +18,8 @@ use crate::{util, ParseResult};
 /// Store info from `#[var]` attribute.
 #[derive(Clone, Debug)]
 pub struct FieldVar {
+    /// What name this variable should have in Godot, if `None` then the Rust name should be used.
+    pub rename: Option<Ident>,
     pub getter: GetterSetter,
     pub setter: GetterSetter,
     pub hint: FieldHint,
@@ -29,13 +31,15 @@ impl FieldVar {
     /// Parse a `#[var]` attribute to a `FieldVar` struct.
     ///
     /// Possible keys:
+    /// - `rename = ident`
     /// - `get = expr`
     /// - `set = expr`
     /// - `hint = ident`
     /// - `hint_string = expr`
     /// - `usage_flags =
     pub(crate) fn new_from_kv(parser: &mut KvParser) -> ParseResult<Self> {
         let span = parser.span();
+        let rename = parser.handle_ident("rename")?;
         let getter = GetterSetter::parse(parser, "get")?;
         let setter = GetterSetter::parse(parser, "set")?;
 
@@ -64,6 +68,7 @@ impl FieldVar {
         };
 
         Ok(FieldVar {
+            rename,
             getter,
             setter,
             hint,
@@ -84,6 +89,7 @@ impl FieldVar {
 impl Default for FieldVar {
     fn default() -> Self {
         Self {
+            rename: Default::default(),
             getter: Default::default(),
             setter: Default::default(),
             hint: Default::default(),
@@ -131,11 +137,12 @@ impl GetterSetter {
         class_name: &Ident,
         kind: GetSet,
         field: &Field,
+        rename: &Option<Ident>,
     ) -> Option<GetterSetterImpl> {
         match self {
             GetterSetter::Omitted => None,
             GetterSetter::Generated => Some(GetterSetterImpl::from_generated_impl(
-                class_name, kind, field,
+                class_name, kind, field, rename,
             )),
             GetterSetter::Custom(function_name) => {
                 Some(GetterSetterImpl::from_custom_impl(function_name))
@@ -173,14 +180,21 @@ pub struct GetterSetterImpl {
 }
 
 impl GetterSetterImpl {
-    fn from_generated_impl(class_name: &Ident, kind: GetSet, field: &Field) -> Self {
+    fn from_generated_impl(
+        class_name: &Ident,
+        kind: GetSet,
+        field: &Field,
+        rename: &Option<Ident>,
+    ) -> Self {
         let Field {
             name: field_name,
             ty: field_type,
             ..
         } = field;
 
-        let function_name = format_ident!("{}{field_name}", kind.prefix());
+        let var_name = rename.as_ref().unwrap_or(field_name);
+
+        let function_name = format_ident!("{}{var_name}", kind.prefix());
 
         let signature;
         let function_body;

godot-macros/src/class/data_models/property.rs

@@ -76,17 +76,17 @@ pub fn make_property_impl(class_name: &Ident, fields: &Fields) -> TokenStream {
         };
 
         make_groups_registrations(group, subgroup, &mut export_tokens, class_name);
-
-        let field_name = field_ident.to_string();
-
         let FieldVar {
+            rename,
             getter,
             setter,
             hint,
             mut usage_flags,
             ..
         } = var;
 
+        let field_name = rename.as_ref().unwrap_or(field_ident).to_string();
+
         let export_hint;
         let registration_fn;
 
@@ -151,14 +151,14 @@ pub fn make_property_impl(class_name: &Ident, fields: &Fields) -> TokenStream {
         // Note: {getter,setter}_tokens can be either a path `Class_Functions::constant_name` or an empty string `""`.
 
         let getter_tokens = make_getter_setter(
-            getter.to_impl(class_name, GetSet::Get, field),
+            getter.to_impl(class_name, GetSet::Get, field, &rename),
             &mut getter_setter_impls,
             &mut func_name_consts,
             &mut export_tokens,
             class_name,
         );
         let setter_tokens = make_getter_setter(
-            setter.to_impl(class_name, GetSet::Set, field),
+            setter.to_impl(class_name, GetSet::Set, field, &rename),
             &mut getter_setter_impls,
             &mut func_name_consts,
             &mut export_tokens,

godot-macros/src/lib.rs

@@ -206,7 +206,23 @@ use crate::util::{bail, ident, KvParser};
 /// }
 /// ```
 ///
-/// To create a property without a backing field to store data, you can use [`PhantomVar`](../obj/struct.PhantomVar.html).
+/// If you want the field to have a different name in Godot and Rust, you can use `rename`:
+///
+/// ```
+/// # use godot::prelude::*;
+/// #[derive(GodotClass)]
+/// # #[class(init)]
+/// struct MyStruct {
+///     #[var(rename = my_godot_field)]
+///     my_rust_field: i64,
+/// }
+/// ```
+///
+/// With this, you can access this field as `my_rust_field` in Rust code, however when accessing it from Godot you have to
+/// use `my_godot_field` instead (including when using methods such as [`Object::get`](../classes/struct.Object.html#method.get)).
+/// The generated getters and setters will also be named `get/set_my_godot_field`, instead of `get/set_my_rust_field`.
+///
+/// To create a property without a backing field to store data, you can use [`PhantomVar`](../prelude/struct.PhantomVar.html).
 /// This disables autogenerated getters and setters for that field.
 ///
 /// ## Export properties -- `#[export]`

itest/rust/src/object_tests/property_test.rs

@@ -53,6 +53,9 @@ struct HasProperty {
 
     #[var]
     packed_int_array: PackedInt32Array,
+
+    #[var(rename = renamed_variable)]
+    unused_name: GString,
 }
 
 #[godot_api]
@@ -147,10 +150,48 @@ impl INode for HasProperty {
             texture_val: OnEditor::default(),
             texture_val_rw: None,
             packed_int_array: PackedInt32Array::new(),
+            unused_name: GString::new(),
         }
     }
 }
 
+#[itest]
+fn test_renamed_var() {
+    let mut obj = HasProperty::new_alloc();
+
+    let prop_list = obj.get_property_list();
+    assert!(prop_list
+        .iter_shared()
+        .any(|d| d.get("name") == Some("renamed_variable".to_variant())));
+    assert!(!prop_list
+        .iter_shared()
+        .any(|d| d.get("name") == Some("unused_name".to_variant())));
+
+    assert_eq!(obj.get("renamed_variable"), GString::new().to_variant());
+    assert_eq!(obj.get("unused_name"), Variant::nil());
+
+    let new_value = "variable changed".to_variant();
+    obj.set("renamed_variable", &new_value);
+    obj.set("unused_name", &"something different".to_variant());
+    assert_eq!(obj.get("renamed_variable"), new_value);
+    assert_eq!(obj.get("unused_name"), Variant::nil());
+
+    obj.free();
+}
+
+#[itest]
+fn test_renamed_var_getter_setter() {
+    let obj = HasProperty::new_alloc();
+
+    assert!(obj.has_method("get_renamed_variable"));
+    assert!(obj.has_method("set_renamed_variable"));
+    assert!(!obj.has_method("get_unused_name"));
+    assert!(!obj.has_method("get_unused_name"));
+    assert_eq!(obj.bind().get_renamed_variable(), GString::new());
+
+    obj.free();
+}
+
 #[derive(Default, Copy, Clone)]
 #[repr(i64)]
 enum SomeCStyleEnum {