Replace GAT with lifetime on trait in node graph

node-graph/gcore/src/value.rs

@@ -1,39 +1,34 @@
-use std::{borrow::Borrow, marker::PhantomData};
-
-use const_default::ConstDefault;
+use std::{any::Any, marker::PhantomData};
 
 use crate::{Exec, Node};
 
 pub struct IntNode<const N: u32>;
-impl<const N: u32> Node for IntNode<N> {
-    type Input<'o> = ();
-    type Output<'i> = u32;
-    fn eval<'a, I: Borrow<Self::Input<'a>>>(&self, _input: I) -> u32 {
+impl<'n, const N: u32> Exec<'n> for IntNode<N> {
+    type Output = u32;
+    fn exec(&self) -> u32 {
         N
     }
 }
 
 #[derive(Default)]
-pub struct ValueNode<T>(T);
-impl<T> Node for ValueNode<T> {
-    type Input<'i> = () where T: 'i;
-    type Output<'o> = &'o T where T: 'o;
-    fn eval<'a, I: Borrow<Self::Input<'a>>>(&'a self, _input: I) -> &T {
+pub struct ValueNode<'n, T>(T, PhantomData<&'n ()>);
+impl<'n, T: 'n> Exec<'n> for ValueNode<'n, T> {
+    type Output = &'n T;
+    fn exec(&'n self) -> &'n T {
         &self.0
     }
 }
-impl<T> ValueNode<T> {
-    pub const fn new(value: T) -> ValueNode<T> {
-        ValueNode(value)
+impl<'n, T> ValueNode<'n, T> {
+    pub const fn new(value: T) -> ValueNode<'n, T> {
+        ValueNode(value, PhantomData)
     }
 }
 
 #[derive(Default)]
 pub struct DefaultNode<T>(PhantomData<T>);
-impl<T: Default> Node for DefaultNode<T> {
-    type Input<'i> = () where T: 'i;
-    type Output<'o> = T where T: 'o;
-    fn eval<'a, I: Borrow<Self::Input<'a>>>(&'a self, _input: I) -> T {
+impl<'n, T: Default + 'n> Exec<'n> for DefaultNode<T> {
+    type Output = T;
+    fn exec(&self) -> T {
         T::default()
     }
 }
@@ -43,23 +38,33 @@ impl<T> DefaultNode<T> {
     }
 }
 
-pub struct DefaultRefNode<T>(ValueNode<T>);
-impl<T: 'static> Node for DefaultRefNode<T> {
-    type Input<'i> = () where T: 'i;
-    type Output<'o> = &'o T where T: 'o;
-    fn eval<'a, I: Borrow<Self::Input<'a>>>(&'a self, _input: I) -> &'a T {
+pub struct AnyRefNode<'n, N: Node<'n, I, Output = &'n O>, I, O>(
+    &'n N,
+    PhantomData<&'n I>,
+    PhantomData<&'n O>,
+);
+impl<'n, N: Node<'n, I, Output = &'n O>, I, O: 'static> Node<'n, I> for AnyRefNode<'n, N, I, O> {
+    type Output = &'n (dyn Any + 'static);
+    fn eval(&'n self, input: &'n I) -> Self::Output {
+        let value: &O = self.0.eval(input);
+        value
+    }
+}
+impl<'n, N: Node<'n, I, Output = &'n O>, I, O: 'static> AnyRefNode<'n, N, I, O> {
+    pub fn new(n: &'n N) -> AnyRefNode<'n, N, I, O> {
+        AnyRefNode(n, PhantomData, PhantomData)
+    }
+}
+
+pub struct DefaultRefNode<'n, T>(ValueNode<'n, T>);
+impl<'n, T: 'n> Exec<'n> for DefaultRefNode<'n, T> {
+    type Output = &'n T;
+    fn exec(&'n self) -> &'n T {
         self.0.exec()
     }
 }
-#[cfg(feature = "const_default")]
-impl<T: ConstDefault> DefaultRefNode<T> {
-    pub const fn new() -> DefaultRefNode<T> {
-        DefaultRefNode(ValueNode::new(T::DEFAULT))
-    }
-}
-#[cfg(not(feature = "const_default"))]
-impl<T: Default> DefaultRefNode<T> {
-    pub fn new() -> DefaultRefNode<T> {
+impl<'n, T: Default> Default for DefaultRefNode<'n, T> {
+    fn default() -> DefaultRefNode<'n, T> {
         DefaultRefNode(ValueNode::new(T::default()))
     }
 }