Own module for typed signals + variadic args

Author: Bromeon

godot-core/src/registry/as_func.rs

@@ -0,0 +1,12 @@
+/*
+ * Copyright (c) godot-rust; Bromeon and contributors.
+ * 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/.
+ */
+
+mod typed_signal;
+mod variadic;
+
+pub use typed_signal::*;
+pub use variadic::*;

godot-core/src/registry/functional/mod.rs

@@ -9,51 +9,11 @@
 
 use crate::builtin::{Callable, Variant};
 use crate::obj::{Gd, GodotClass, WithBaseField};
-use crate::registry::as_func::AsFunc;
-use crate::{classes, meta, sys};
+use crate::registry::functional::{AsFunc, ParamTuple};
+use crate::{classes, sys};
 use std::borrow::Cow;
 use std::fmt;
 
-pub trait ParamTuple {
-    fn to_variant_array(&self) -> Vec<Variant>;
-    fn from_variant_array(array: &[&Variant]) -> Self;
-}
-
-macro_rules! impl_param_tuple {
-    // Recursive case for tuple with N elements
-    ($($args:ident : $Ps:ident),*) => {
-        impl<$($Ps),*> ParamTuple for ($($Ps,)*)
-        where
-            $($Ps: meta::ToGodot + meta::FromGodot),*
-        {
-            fn to_variant_array(&self) -> Vec<Variant> {
-                let ($($args,)*) = self;
-
-                vec![
-                    $( $args.to_variant(), )*
-                ]
-            }
-
-            #[allow(unused_variables, unused_mut, clippy::unused_unit)]
-            fn from_variant_array(array: &[&Variant]) -> Self {
-               let mut iter = array.iter();
-               ( $(
-                  <$Ps>::from_variant(
-                        iter.next().unwrap_or_else(|| panic!("ParamTuple: {} access out-of-bounds (len {})", stringify!($args), array.len()))
-                  ),
-               )* )
-            }
-        }
-    };
-}
-
-impl_param_tuple!();
-impl_param_tuple!(arg0: P0);
-impl_param_tuple!(arg0: P0, arg1: P1);
-impl_param_tuple!(arg0: P0, arg1: P1, arg2: P2);
-
-// ----------------------------------------------------------------------------------------------------------------------------------------------
-
 #[doc(hidden)]
 pub enum ObjectRef<'a, C: GodotClass> {
     /// Helpful for emit: reuse `&self` from within the `impl` block, goes through `base()` re-borrowing and thus allows re-entrant calls
@@ -167,62 +127,6 @@ impl<'a, C: WithBaseField, Ps: ParamTuple> TypedSignal<'a, C, Ps> {
     }
 }
 
-// ----------------------------------------------------------------------------------------------------------------------------------------------
-/* Previous impl based on assumption, Signal would be used. Could maybe be combined within an enum.
-
-pub struct TypedSignal<Ps> {
-    signal: Signal,
-    _signature: std::marker::PhantomData<Ps>,
-}
-
-impl<Ps: ParamTuple> TypedSignal<Ps> {
-    pub(crate) fn from_untyped(signal: Signal) -> Self {
-        Self {
-            signal,
-            _signature: std::marker::PhantomData,
-        }
-    }
-
-    pub fn emit(&self, params: Ps) {
-        self.signal.emit(&params.to_variant_array());
-    }
-
-    pub fn connect_untyped(&mut self, callable: &Callable, flags: i64) {
-        self.signal.connect(callable, flags);
-    }
-
-    pub fn to_untyped(&self) -> Signal {
-        self.signal.clone()
-    }
-}*/
-
-// ----------------------------------------------------------------------------------------------------------------------------------------------
-
-/*
-pub struct TypedFunc<C, R, Ps> {
-    godot_name: &'static str,
-    _return_type: std::marker::PhantomData<R>,
-    _param_types: std::marker::PhantomData<(C, Ps)>,
-}
-
-impl<C: GodotClass, R, Ps> TypedFunc<C, R, Ps> {
-    #[doc(hidden)]
-    pub fn from_godot_name(godot_name: &'static str) -> Self {
-        Self {
-            godot_name,
-            _return_type: std::marker::PhantomData,
-            _param_types: std::marker::PhantomData,
-        }
-    }
-
-    pub fn with_object<T: GodotClass>(obj: &Gd<T>) {}
-
-    pub fn godot_name(&self) -> &'static str {
-        self.godot_name
-    }
-}
-*/
-
 // ----------------------------------------------------------------------------------------------------------------------------------------------
 
 /// Type-safe `#[func]` reference that is readily callable.

godot-core/src/registry/typed_signal.rs renamed to godot-core/src/registry/functional/typed_signal.rs

@@ -0,0 +1,85 @@
+/*
+ * Copyright (c) godot-rust; Bromeon and contributors.
+ * 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/.
+ */
+
+//! Emulates variadic argument lists (via tuples), related to functions and signals.
+
+// https://geo-ant.github.io/blog/2021/rust-traits-and-variadic-functions
+//
+// Could be generalized with R return type, and not special-casing `self`. But keep simple until actually needed.
+
+use crate::builtin::Variant;
+use crate::meta;
+
+pub trait AsFunc<I, Ps> {
+    fn call(&mut self, maybe_instance: I, params: Ps);
+}
+
+macro_rules! impl_signal_recipient {
+    ($( $args:ident : $Ps:ident ),*) => {
+        // Global and associated functions.
+        impl<F, R, $($Ps,)*> AsFunc<(), ( $($Ps,)* )> for F
+            where F: FnMut( $($Ps,)* ) -> R
+        {
+            fn call(&mut self, _no_instance: (), ($($args,)*): ( $($Ps,)* )) {
+                self($($args,)*);
+            }
+        }
+
+        // Methods.
+        impl<F, R, C, $($Ps,)*> AsFunc<&mut C, ( $($Ps,)* )> for F
+            where F: FnMut( &mut C, $($Ps,)* ) -> R
+        {
+            fn call(&mut self, instance: &mut C, ($($args,)*): ( $($Ps,)* )) {
+                self(instance, $($args,)*);
+            }
+        }
+    };
+}
+
+impl_signal_recipient!();
+impl_signal_recipient!(arg0: P0);
+impl_signal_recipient!(arg0: P0, arg1: P1);
+impl_signal_recipient!(arg0: P0, arg1: P1, arg2: P2);
+
+// ----------------------------------------------------------------------------------------------------------------------------------------------
+
+pub trait ParamTuple {
+    fn to_variant_array(&self) -> Vec<Variant>;
+    fn from_variant_array(array: &[&Variant]) -> Self;
+}
+
+macro_rules! impl_param_tuple {
+    ($($args:ident : $Ps:ident),*) => {
+        impl<$($Ps),*> ParamTuple for ($($Ps,)*)
+        where
+            $($Ps: meta::ToGodot + meta::FromGodot),*
+        {
+            fn to_variant_array(&self) -> Vec<Variant> {
+                let ($($args,)*) = self;
+
+                vec![
+                    $( $args.to_variant(), )*
+                ]
+            }
+
+            #[allow(unused_variables, unused_mut, clippy::unused_unit)]
+            fn from_variant_array(array: &[&Variant]) -> Self {
+               let mut iter = array.iter();
+               ( $(
+                  <$Ps>::from_variant(
+                        iter.next().unwrap_or_else(|| panic!("ParamTuple: {} access out-of-bounds (len {})", stringify!($args), array.len()))
+                  ),
+               )* )
+            }
+        }
+    };
+}
+
+impl_param_tuple!();
+impl_param_tuple!(arg0: P0);
+impl_param_tuple!(arg0: P0, arg1: P1);
+impl_param_tuple!(arg0: P0, arg1: P1, arg2: P2);

godot-core/src/registry/functional/variadic.rs

@@ -16,9 +16,11 @@ pub mod plugin;
 pub mod property;
 
 #[cfg(since_api = "4.2")]
-pub mod as_func;
-#[cfg(since_api = "4.2")]
-pub mod typed_signal;
+pub mod functional;
+
+// Contents re-exported in `godot` crate; just keep empty.
+#[cfg(before_api = "4.2")]
+pub mod functional {}
 
 // RpcConfig uses MultiplayerPeer::TransferMode and MultiplayerApi::RpcMode, which are only enabled in `codegen-full` feature.
 #[cfg(feature = "codegen-full")]

godot-core/src/registry/mod.rs

@@ -183,17 +183,13 @@ pub mod init {
 
 /// Register/export Rust symbols to Godot: classes, methods, enums...
 pub mod register {
+    pub use godot_core::registry::functional::*;
     pub use godot_core::registry::property;
     pub use godot_macros::{godot_api, godot_dyn, Export, GodotClass, GodotConvert, Var};
 
     #[cfg(feature = "__codegen-full")]
     pub use godot_core::registry::RpcConfig;
 
-    #[cfg(since_api = "4.2")]
-    pub use godot_core::registry::as_func::*;
-    #[cfg(since_api = "4.2")]
-    pub use godot_core::registry::typed_signal::*;
-
     /// Re-exports used by proc-macro API.
     #[doc(hidden)]
     pub mod private {

godot/src/lib.rs

@@ -124,12 +124,14 @@ impl Emitter {
 
     // "Internal" means connect/emit happens from within the class (via &mut self).
 
+    #[cfg(since_api = "4.2")]
     fn connect_signals_internal(&mut self) {
         let mut sig = self.signals().emitter_1();
         sig.connect_self(Self::self_receive);
         sig.connect(Self::self_receive_static);
     }
 
+    #[cfg(since_api = "4.2")]
     fn emit_signals_internal(&mut self) {
         self.signals().emitter_1().emit(1234);
     }