Try and fail to make nodes object-safe in node graph

node-graph/gcore/src/generic.rs

@@ -0,0 +1,39 @@
+use std::{borrow::Borrow, marker::PhantomData};
+
+use crate::Node;
+pub struct FnNode<T: Fn(&In) -> O, In, O>(T, PhantomData<In>, PhantomData<O>);
+impl<T: Fn(&In) -> O, In, O> Node for FnNode<T, In, O> {
+    type Output<'a> = O where Self: 'a;
+    type Input<'a> = In where Self: 'a;
+
+    fn eval<'a, I: Borrow<Self::Input<'a>>>(&'a self, input: I) -> Self::Output<'a> {
+        self.0(input.borrow())
+    }
+}
+
+impl<T: Fn(&In) -> O, In, O> FnNode<T, In, O> {
+    pub fn new(f: T) -> Self {
+        FnNode(f, PhantomData::default(), PhantomData::default())
+    }
+}
+
+pub struct FnNodeWithState<T: Fn(&In, &State) -> O, In, O, State>(
+    T,
+    State,
+    PhantomData<In>,
+    PhantomData<O>,
+);
+impl<T: Fn(&In, &State) -> O, In, O, State> Node for FnNodeWithState<T, In, O, State> {
+    type Output<'a> = O where Self: 'a;
+    type Input<'a> = In where Self: 'a;
+
+    fn eval<'a, I: Borrow<Self::Input<'a>>>(&'a self, input: I) -> Self::Output<'a> {
+        self.0(input.borrow(), &self.1)
+    }
+}
+
+impl<T: Fn(&In, &State) -> O, In, O, State> FnNodeWithState<T, In, O, State> {
+    pub fn new(f: T, state: State) -> Self {
+        FnNodeWithState(f, state, PhantomData::default(), PhantomData::default())
+    }
+}