Migrate memo nodes to node macro and make implementing other persistent nodes easier (#3552)

* Add #[data] and #[serialize] attributes to node macro

- Add #[data] attribute for struct fields that aren't node parameters
  - Data fields are initialized with Default::default()
  - Passed as references to the underlying function
  - Excluded from registry metadata (internal state)
  - Generic types in data fields allowed without #[implementations]

- Add #[serialize] attribute for custom Node::serialize() implementation
  - Receives references to all data fields
  - Generates serialize() method in Node trait impl

- Conditional derives based on data field presence
  - With data fields: Debug, Clone only
  - Without data fields: Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash

* Refactor Memo and Monitor Node to use node macro

* Move Complex type into type alias

* Fix format

* Update node-graph/nodes/gcore/src/memo.rs

Co-authored-by: Keavon Chambers <keavon@keavon.com>

* Update node-graph/nodes/gcore/src/memo.rs

Co-authored-by: Keavon Chambers <keavon@keavon.com>

---------

Co-authored-by: Keavon Chambers <keavon@keavon.com>

node-graph/node-macro/src/codegen.rs

@@ -37,33 +37,102 @@ pub(crate) fn generate_node_code(crate_ident: &CrateIdent, parsed: &ParsedNodeFn
 	};
 	let struct_name = format_ident!("{}Node", struct_name);
 
-	let struct_generics: Vec<Ident> = fields.iter().enumerate().map(|(i, _)| format_ident!("Node{}", i)).collect();
+	// Separate data fields from regular fields
+	let (data_fields, regular_fields): (Vec<_>, Vec<_>) = fields.iter().partition(|f| f.is_data_field);
+
+	// Extract function generics used by data fields
+	let data_field_generics: Vec<_> = fn_generics
+		.iter()
+		.filter(|generic| {
+			let generic_ident = match generic {
+				syn::GenericParam::Type(type_param) => &type_param.ident,
+				_ => return false,
+			};
+
+			// Check if this generic is used in any data field type
+			data_fields.iter().any(|field| match &field.ty {
+				ParsedFieldType::Regular(RegularParsedField { ty, .. }) => type_contains_ident(ty, generic_ident),
+				_ => false,
+			})
+		})
+		.cloned()
+		.collect();
+
+	// Node generics for regular fields (Node0, Node1, ...)
+	let node_generics: Vec<Ident> = regular_fields.iter().enumerate().map(|(i, _)| format_ident!("Node{}", i)).collect();
+
+	// Extract just the idents from data_field_generics for struct type parameters
+	let data_field_generic_idents: Vec<Ident> = data_field_generics
+		.iter()
+		.filter_map(|gp| match gp {
+			syn::GenericParam::Type(tp) => Some(tp.ident.clone()),
+			_ => None,
+		})
+		.collect();
+
+	// Combined struct type parameters: data field generic idents (T, U, ...) + node generics (Node0, Node1, ...)
+	// For struct type instantiation: MemoNode<T, Node0>
+	let struct_type_params: Vec<Ident> = data_field_generic_idents.iter().cloned().chain(node_generics.iter().cloned()).collect();
+
+	// Combined struct generic parameters with bounds for struct definition
+	// struct MemoNode<T: Clone, Node0>
+	let struct_generic_params: Vec<TokenStream2> = data_field_generics.iter().map(|gp| quote!(#gp)).chain(node_generics.iter().map(|id| quote!(#id))).collect();
 	let input_ident = &input.pat_ident;
 
 	let context_features = &input.context_features;
 
-	let field_idents: Vec<_> = fields.iter().map(|f| &f.pat_ident).collect();
+	// Regular field idents and names (for function parameters)
+	let field_idents: Vec<_> = regular_fields.iter().map(|f| &f.pat_ident).collect();
 	let field_names: Vec<_> = field_idents.iter().map(|pat_ident| &pat_ident.ident).collect();
+	let regular_field_names: Vec<_> = regular_fields.iter().map(|f| &f.pat_ident.ident).collect();
+	let data_field_names: Vec<_> = data_fields.iter().map(|f| &f.pat_ident.ident).collect();
 
-	let input_names: Vec<_> = fields
+	// Only regular fields have input names/descriptions (for UI)
+	let input_names: Vec<_> = regular_fields
 		.iter()
 		.map(|f| &f.name)
-		.zip(field_names.iter())
+		.zip(regular_field_names.iter())
 		.map(|zipped| match zipped {
 			(Some(name), _) => name.value(),
 			(_, name) => name.to_string().to_case(Case::Title),
 		})
 		.collect();
 
-	let input_descriptions: Vec<_> = fields.iter().map(|f| &f.description).collect();
+	let input_descriptions: Vec<_> = regular_fields.iter().map(|f| &f.description).collect();
 
-	let struct_fields = field_names.iter().zip(struct_generics.iter()).map(|(name, r#gen)| {
+	// Generate struct fields: data fields (concrete types) + regular fields (generic types)
+	let data_field_defs = data_fields.iter().map(|field| {
+		let name = &field.pat_ident.ident;
+		let ty = match &field.ty {
+			ParsedFieldType::Regular(RegularParsedField { ty, .. }) => ty,
+			_ => unreachable!("Data fields must be Regular types, not Node types"),
+		};
+		quote! { pub(super) #name: #ty }
+	});
+
+	let regular_field_defs = regular_field_names.iter().zip(node_generics.iter()).map(|(name, r#gen)| {
 		quote! { pub(super) #name: #r#gen }
 	});
 
+	let struct_fields = data_field_defs.chain(regular_field_defs);
+
 	let mut future_idents = Vec::new();
 
-	let field_types: Vec<_> = fields
+	// Data fields get passed as references to the underlying function
+	let data_field_idents: Vec<_> = data_fields.iter().map(|f| &f.pat_ident).collect();
+	let data_field_types: Vec<_> = data_fields
+		.iter()
+		.map(|field| match &field.ty {
+			ParsedFieldType::Regular(RegularParsedField { ty, .. }) => {
+				let ty = ty.clone();
+				quote!(&#ty)
+			}
+			_ => unreachable!("Data fields must be Regular types, not Node types"),
+		})
+		.collect();
+
+	// Regular fields have types passed to the function
+	let field_types: Vec<_> = regular_fields
 		.iter()
 		.map(|field| match &field.ty {
 			ParsedFieldType::Regular(RegularParsedField { ty, .. }) => ty.clone(),
@@ -74,7 +143,8 @@ pub(crate) fn generate_node_code(crate_ident: &CrateIdent, parsed: &ParsedNodeFn
 		})
 		.collect();
 
-	let widget_override: Vec<_> = fields
+	// Only regular fields have UI metadata (data fields are internal state)
+	let widget_override: Vec<_> = regular_fields
 		.iter()
 		.map(|field| match &field.widget_override {
 			ParsedWidgetOverride::None => quote!(RegistryWidgetOverride::None),
@@ -84,7 +154,7 @@ pub(crate) fn generate_node_code(crate_ident: &CrateIdent, parsed: &ParsedNodeFn
 		})
 		.collect();
 
-	let value_sources: Vec<_> = fields
+	let value_sources: Vec<_> = regular_fields
 		.iter()
 		.map(|field| match &field.ty {
 			ParsedFieldType::Regular(RegularParsedField { value_source, .. }) => match value_source {
@@ -104,7 +174,7 @@ pub(crate) fn generate_node_code(crate_ident: &CrateIdent, parsed: &ParsedNodeFn
 		})
 		.collect();
 
-	let default_types: Vec<_> = fields
+	let default_types: Vec<_> = regular_fields
 		.iter()
 		.map(|field| match &field.ty {
 			ParsedFieldType::Regular(RegularParsedField { implementations, .. }) => match implementations.first() {
@@ -115,7 +185,7 @@ pub(crate) fn generate_node_code(crate_ident: &CrateIdent, parsed: &ParsedNodeFn
 		})
 		.collect();
 
-	let number_min_values: Vec<_> = fields
+	let number_min_values: Vec<_> = regular_fields
 		.iter()
 		.map(|field| match &field.ty {
 			ParsedFieldType::Regular(RegularParsedField { number_soft_min, number_hard_min, .. }) => match (number_soft_min, number_hard_min) {
@@ -126,7 +196,7 @@ pub(crate) fn generate_node_code(crate_ident: &CrateIdent, parsed: &ParsedNodeFn
 			_ => quote!(None),
 		})
 		.collect();
-	let number_max_values: Vec<_> = fields
+	let number_max_values: Vec<_> = regular_fields
 		.iter()
 		.map(|field| match &field.ty {
 			ParsedFieldType::Regular(RegularParsedField { number_soft_max, number_hard_max, .. }) => match (number_soft_max, number_hard_max) {
@@ -137,7 +207,7 @@ pub(crate) fn generate_node_code(crate_ident: &CrateIdent, parsed: &ParsedNodeFn
 			_ => quote!(None),
 		})
 		.collect();
-	let number_mode_range_values: Vec<_> = fields
+	let number_mode_range_values: Vec<_> = regular_fields
 		.iter()
 		.map(|field| match &field.ty {
 			ParsedFieldType::Regular(RegularParsedField {
@@ -147,15 +217,15 @@ pub(crate) fn generate_node_code(crate_ident: &CrateIdent, parsed: &ParsedNodeFn
 			_ => quote!(None),
 		})
 		.collect();
-	let number_display_decimal_places: Vec<_> = fields
+	let number_display_decimal_places: Vec<_> = regular_fields
 		.iter()
 		.map(|field| field.number_display_decimal_places.as_ref().map_or(quote!(None), |i| quote!(Some(#i))))
 		.collect();
-	let number_step: Vec<_> = fields.iter().map(|field| field.number_step.as_ref().map_or(quote!(None), |i| quote!(Some(#i)))).collect();
+	let number_step: Vec<_> = regular_fields.iter().map(|field| field.number_step.as_ref().map_or(quote!(None), |i| quote!(Some(#i)))).collect();
 
-	let unit_suffix: Vec<_> = fields.iter().map(|field| field.unit.as_ref().map_or(quote!(None), |i| quote!(Some(#i)))).collect();
+	let unit_suffix: Vec<_> = regular_fields.iter().map(|field| field.unit.as_ref().map_or(quote!(None), |i| quote!(Some(#i)))).collect();
 
-	let exposed: Vec<_> = fields
+	let exposed: Vec<_> = regular_fields
 		.iter()
 		.map(|field| match &field.ty {
 			ParsedFieldType::Regular(RegularParsedField { exposed, .. }) => quote!(#exposed),
@@ -163,7 +233,8 @@ pub(crate) fn generate_node_code(crate_ident: &CrateIdent, parsed: &ParsedNodeFn
 		})
 		.collect();
 
-	let eval_args = fields.iter().map(|field| {
+	// Only eval regular fields (data fields are accessed directly as self.field_name)
+	let eval_args = regular_fields.iter().map(|field| {
 		let name = &field.pat_ident.ident;
 		match &field.ty {
 			ParsedFieldType::Regular { .. } => {
@@ -175,7 +246,8 @@ pub(crate) fn generate_node_code(crate_ident: &CrateIdent, parsed: &ParsedNodeFn
 		}
 	});
 
-	let min_max_args = fields.iter().map(|field| match &field.ty {
+	// Only regular fields can have min/max constraints
+	let min_max_args = regular_fields.iter().map(|field| match &field.ty {
 		ParsedFieldType::Regular(RegularParsedField { number_hard_min, number_hard_max, .. }) => {
 			let name = &field.pat_ident.ident;
 			let mut tokens = quote!();
@@ -208,7 +280,7 @@ pub(crate) fn generate_node_code(crate_ident: &CrateIdent, parsed: &ParsedNodeFn
 	let mut clauses = Vec::new();
 	let mut clampable_clauses = Vec::new();
 
-	for (field, name) in fields.iter().zip(struct_generics.iter()) {
+	for (field, name) in regular_fields.iter().zip(node_generics.iter()) {
 		clauses.push(match (&field.ty, *is_async) {
 			(
 				ParsedFieldType::Regular(RegularParsedField {
@@ -259,13 +331,42 @@ pub(crate) fn generate_node_code(crate_ident: &CrateIdent, parsed: &ParsedNodeFn
 	);
 	struct_where_clause.predicates.extend(extra_where);
 
-	let new_args = struct_generics.iter().zip(field_names.iter()).map(|(r#gen, name)| {
+	// Only regular fields are parameters to new()
+	let new_args = node_generics.iter().zip(regular_field_names.iter()).map(|(r#gen, name)| {
 		quote! { #name: #r#gen }
 	});
 
+	// Initialize data fields with Default, regular fields with parameters
+	let data_inits = data_field_names.iter().map(|name| {
+		quote! { #name: Default::default() }
+	});
+	let regular_inits = regular_field_names.iter().map(|name| {
+		quote! { #name }
+	});
+	let all_field_inits = data_inits.chain(regular_inits);
+
 	let async_keyword = is_async.then(|| quote!(async));
 	let await_keyword = is_async.then(|| quote!(.await));
 
+	// Data fields may not implement Copy, PartialEq, etc., so only derive Debug and Clone
+	let struct_derives = if data_fields.is_empty() {
+		quote!(#[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)])
+	} else {
+		quote!(#[derive(Debug, Clone)])
+	};
+
+	// Generate serialize method if serialize attribute is specified
+	let serialize_impl = if let Some(serialize_fn) = &parsed.attributes.serialize {
+		let data_field_refs = data_field_names.iter().map(|name| quote!(&self.#name));
+		quote! {
+			fn serialize(&self) -> Option<std::sync::Arc<dyn std::any::Any + Send + Sync>> {
+				#serialize_fn(#(#data_field_refs),*)
+			}
+		}
+	} else {
+		quote!()
+	};
+
 	let eval_impl = quote! {
 		type Output = #core_types::registry::DynFuture<'n, #output_type>;
 		#[inline]
@@ -275,9 +376,11 @@ pub(crate) fn generate_node_code(crate_ident: &CrateIdent, parsed: &ParsedNodeFn
 
 				#(#eval_args)*
 				#(#min_max_args)*
-				self::#fn_name(__input #(, #field_names)*) #await_keyword
+				self::#fn_name(__input #(, &self.#data_field_names)* #(, #regular_field_names)*) #await_keyword
 			})
 		}
+
+		#serialize_impl
 	};
 
 	let identifier = format_ident!("{}_proto_ident", fn_name);
@@ -302,11 +405,11 @@ pub(crate) fn generate_node_code(crate_ident: &CrateIdent, parsed: &ParsedNodeFn
 		/// Underlying implementation for [#struct_name]
 		#[inline]
 		#[allow(clippy::too_many_arguments)]
-		#vis #async_keyword fn #fn_name <'n, #(#fn_generics,)*> (#input_ident: #input_type #(, #field_idents: #field_types)*) -> #output_type #where_clause #body
+		#vis #async_keyword fn #fn_name <'n, #(#fn_generics,)*> (#input_ident: #input_type #(, #data_field_idents: #data_field_types)* #(, #field_idents: #field_types)*) -> #output_type #where_clause #body
 
 		#cfg
 		#[automatically_derived]
-		impl<'n, #(#fn_generics,)* #(#struct_generics,)* #(#future_idents,)*> #core_types::Node<'n, #input_type> for #mod_name::#struct_name<#(#struct_generics,)*>
+		impl<'n, #(#fn_generics,)* #(#node_generics,)* #(#future_idents,)*> #core_types::Node<'n, #input_type> for #mod_name::#struct_name<#(#struct_type_params,)*>
 		#struct_where_clause
 		{
 			#eval_impl
@@ -340,18 +443,18 @@ pub(crate) fn generate_node_code(crate_ident: &CrateIdent, parsed: &ParsedNodeFn
 
 			static #import_name: core::marker::PhantomData<(#(#all_implementation_types,)*)> = core::marker::PhantomData;
 
-			#[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
-			pub struct #struct_name<#(#struct_generics,)*> {
+			#struct_derives
+			pub struct #struct_name<#(#struct_generic_params,)*> {
 				#(#struct_fields,)*
 			}
 
 			#[automatically_derived]
-			impl<'n, #(#struct_generics,)*> #struct_name<#(#struct_generics,)*>
+			impl<'n, #(#struct_generic_params,)*> #struct_name<#(#struct_type_params,)*>
 			{
 				#[allow(clippy::too_many_arguments)]
 				pub fn new(#(#new_args,)*) -> Self {
 					Self {
-						#(#field_names,)*
+						#(#all_field_inits,)*
 					}
 				}
 			}
@@ -493,8 +596,10 @@ fn generate_register_node_impl(parsed: &ParsedNodeFn, field_names: &[&Ident], st
 
 	let mut constructors = Vec::new();
 	let unit = parse_quote!(gcore::Context);
-	let parameter_types: Vec<_> = parsed
-		.fields
+
+	let regular_fields: Vec<_> = parsed.fields.iter().filter(|f| !f.is_data_field).collect();
+
+	let parameter_types: Vec<_> = regular_fields
 		.iter()
 		.map(|field| {
 			match &field.ty {
@@ -535,7 +640,7 @@ fn generate_register_node_impl(parsed: &ParsedNodeFn, field_names: &[&Ident], st
 			let field_name = field_names[j];
 			let (input_type, output_type) = &types[i.min(types.len() - 1)];
 
-			let node = matches!(parsed.fields[j].ty, ParsedFieldType::Node { .. });
+			let node = matches!(regular_fields[j].ty, ParsedFieldType::Node { .. });
 
 			let downcast_node = quote!(
 				let #field_name: DowncastBothNode<#input_type, #output_type> = DowncastBothNode::new(args[#j].clone());
@@ -712,3 +817,23 @@ impl FilterUsedGenerics {
 		self.used(&*modified).cloned().collect()
 	}
 }
+
+/// Check if a type contains a reference to a specific identifier (e.g., a generic type parameter)
+fn type_contains_ident(ty: &Type, ident: &Ident) -> bool {
+	struct IdentChecker<'a> {
+		target: &'a Ident,
+		found: bool,
+	}
+
+	impl<'a, 'ast> syn::visit::Visit<'ast> for IdentChecker<'a> {
+		fn visit_ident(&mut self, i: &'ast Ident) {
+			if i == self.target {
+				self.found = true;
+			}
+		}
+	}
+
+	let mut checker = IdentChecker { target: ident, found: false };
+	syn::visit::visit_type(&mut checker, ty);
+	checker.found
+}