Merge pull request godot-rust#378 from you-win/feature/func-renaming

Feature/func renaming

godot-macros/src/derive_godot_class/property/field_var.rs

@@ -6,6 +6,7 @@
 
 use crate::derive_godot_class::{make_existence_check, Field, FieldHint};
 use crate::method_registration::make_method_registration;
+use crate::method_registration::FuncDefinition;
 use crate::util::KvParser;
 use crate::{util, ParseResult};
 use proc_macro2::{Ident, TokenStream};
@@ -188,7 +189,13 @@ impl GetterSetterImpl {
         };
 
         let signature = util::parse_signature(signature);
-        let export_token = make_method_registration(class_name, signature);
+        let export_token = make_method_registration(
+            class_name,
+            FuncDefinition {
+                func: signature,
+                rename: None,
+            },
+        );
 
         Self {
             function_name,

godot-macros/src/godot_api.rs

@@ -4,9 +4,12 @@
  * file, You can obtain one at https://mozilla.org/MPL/2.0/.
  */
 
-use crate::method_registration::{make_method_registration, make_virtual_method_callback};
+use crate::method_registration::{
+    make_method_registration, make_virtual_method_callback, FuncDefinition,
+};
 use crate::util;
 use crate::util::bail;
+use crate::util::KvParser;
 use proc_macro2::{Ident, TokenStream};
 use quote::quote;
 use quote::spanned::Spanned;
@@ -46,7 +49,7 @@ pub fn transform(input_decl: Declaration) -> Result<TokenStream, Error> {
 
 /// Attribute for user-declared function
 enum BoundAttrType {
-    Func(AttributeValue),
+    Func { rename: Option<String> },
     Signal(AttributeValue),
     Const(AttributeValue),
 }
@@ -108,7 +111,7 @@ fn transform_inherent_impl(mut decl: Impl) -> Result<TokenStream, Error> {
 
     let methods_registration = funcs
         .into_iter()
-        .map(|func| make_method_registration(&class_name, func));
+        .map(|func_def| make_method_registration(&class_name, func_def));
 
     let consts = process_godot_constants(&mut decl)?;
     let mut integer_constant_names = Vec::new();
@@ -198,8 +201,8 @@ fn transform_inherent_impl(mut decl: Impl) -> Result<TokenStream, Error> {
     Ok(result)
 }
 
-fn process_godot_fns(decl: &mut Impl) -> Result<(Vec<Function>, Vec<Function>), Error> {
-    let mut func_signatures = vec![];
+fn process_godot_fns(decl: &mut Impl) -> Result<(Vec<FuncDefinition>, Vec<Function>), Error> {
+    let mut func_definitions = vec![];
     let mut signal_signatures = vec![];
 
     let mut removed_indexes = vec![];
@@ -229,10 +232,10 @@ fn process_godot_fns(decl: &mut Impl) -> Result<(Vec<Function>, Vec<Function>),
             }
 
             match attr.ty {
-                BoundAttrType::Func(_attr) => {
+                BoundAttrType::Func { rename } => {
                     // Signatures are the same thing without body
                     let sig = util::reduce_to_signature(method);
-                    func_signatures.push(sig);
+                    func_definitions.push(FuncDefinition { func: sig, rename });
                 }
                 BoundAttrType::Signal(ref _attr_val) => {
                     if method.return_ty.is_some() {
@@ -259,7 +262,7 @@ fn process_godot_fns(decl: &mut Impl) -> Result<(Vec<Function>, Vec<Function>),
         decl.body_items.remove(index);
     }
 
-    Ok((func_signatures, signal_signatures))
+    Ok((func_definitions, signal_signatures))
 }
 
 fn process_godot_constants(decl: &mut Impl) -> Result<Vec<Constant>, Error> {
@@ -275,7 +278,7 @@ fn process_godot_constants(decl: &mut Impl) -> Result<Vec<Constant>, Error> {
             constant.attributes.remove(attr.index);
 
             match attr.ty {
-                BoundAttrType::Func(_) => {
+                BoundAttrType::Func { .. } => {
                     return bail!(constant, "#[func] can only be used on functions")
                 }
                 BoundAttrType::Signal(_) => {
@@ -308,11 +311,20 @@ where
             .expect("get_single_path_segment");
 
         let new_found = match attr_name {
-            name if name == "func" => Some(BoundAttr {
-                attr_name: attr_name.clone(),
-                index,
-                ty: BoundAttrType::Func(attr.value.clone()),
-            }),
+            name if name == "func" => {
+                // TODO you-win (August 8, 2023): handle default values here as well?
+
+                // Safe unwrap since #[func] must be present if we got to this point
+                let mut parser = KvParser::parse(attributes, "func")?.unwrap();
+
+                let rename = parser.handle_expr("rename")?.map(|ts| ts.to_string());
+
+                Some(BoundAttr {
+                    attr_name: attr_name.clone(),
+                    index,
+                    ty: BoundAttrType::Func { rename },
+                })
+            }
             name if name == "signal" => {
                 // TODO once parameters are supported, this should probably be moved to the struct definition
                 // E.g. a zero-sized type Signal<(i32, String)> with a provided emit(i32, String) method

godot-macros/src/method_registration/mod.rs

@@ -27,6 +27,14 @@ struct SignatureInfo {
     pub ret_type: TokenStream,
 }
 
+/// Information used for registering a Rust function with Godot.
+pub struct FuncDefinition {
+    /// Raw information about the Rust function.
+    pub func: venial::Function,
+    /// The name the function will be exposed as in Godot. If `None`, the Rust function name is used.
+    pub rename: Option<String>,
+}
+
 /// Returns a closure expression that forwards the parameters to the Rust instance.
 fn make_forwarding_closure(class_name: &Ident, signature_info: &SignatureInfo) -> TokenStream {
     let method_name = &signature_info.method_name;

godot-macros/src/method_registration/register_method.rs

@@ -15,9 +15,9 @@ use quote::quote;
 /// Generates code that registers the specified method for the given class.
 pub fn make_method_registration(
     class_name: &Ident,
-    method_signature: venial::Function,
+    func_definition: super::FuncDefinition,
 ) -> TokenStream {
-    let signature_info = get_signature_info(&method_signature);
+    let signature_info = get_signature_info(&func_definition.func);
     let sig_tuple =
         util::make_signature_tuple_type(&signature_info.ret_type, &signature_info.param_types);
 
@@ -33,7 +33,11 @@ pub fn make_method_registration(
 
     // String literals
     let class_name_str = class_name.to_string();
-    let method_name_str = method_name.to_string();
+    let method_name_str = if let Some(rename) = func_definition.rename {
+        rename
+    } else {
+        method_name.to_string()
+    };
     let param_ident_strs = param_idents.iter().map(|ident| ident.to_string());
 
     quote! {

itest/godot/ManualFfiTests.gd

@@ -289,3 +289,18 @@ func test_option_export():
 	assert_eq(obj.optional_export, null)
 
 	test_node.free()
+
+func test_func_rename():
+	var func_rename := FuncRename.new()
+
+	assert_eq(func_rename.has_method("long_function_name_for_is_true"), false)
+	assert_eq(func_rename.has_method("is_true"), true)
+	assert_eq(func_rename.is_true(), true)
+
+	assert_eq(func_rename.has_method("give_one_inner"), false)
+	assert_eq(func_rename.has_method("give_one"), true)
+	assert_eq(func_rename.give_one(), 1)
+
+	assert_eq(func_rename.has_method("renamed_static"), false)
+	assert_eq(func_rename.has_method("spell_static"), true)
+	assert_eq(func_rename.spell_static(), "static")

itest/rust/src/func_test.rs

@@ -0,0 +1,48 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+use godot::prelude::*;
+
+#[derive(GodotClass)]
+#[class(base=RefCounted)]
+struct FuncRename;
+
+#[godot_api]
+impl FuncRename {
+    #[func(rename=is_true)]
+    fn long_function_name_for_is_true(&self) -> bool {
+        true
+    }
+
+    #[func(rename=give_one)]
+    fn give_one_inner(&self) -> i32 {
+        self.give_one()
+    }
+
+    #[func(rename=spell_static)]
+    fn renamed_static() -> GodotString {
+        GodotString::from("static")
+    }
+}
+
+impl FuncRename {
+    /// Unused but present to demonstrate how `rename = ...` can be used to avoid name clashes.
+    #[allow(dead_code)]
+    fn is_true(&self) -> bool {
+        false
+    }
+
+    fn give_one(&self) -> i32 {
+        1
+    }
+}
+
+#[godot_api]
+impl RefCountedVirtual for FuncRename {
+    fn init(_base: Base<Self::Base>) -> Self {
+        Self
+    }
+}

itest/rust/src/lib.rs

@@ -19,6 +19,7 @@ mod color_test;
 mod derive_variant;
 mod dictionary_test;
 mod enum_test;
+mod func_test;
 mod gdscript_ffi_test;
 mod init_test;
 mod native_structures_test;