update the hierarchical-tree for hanlder data

editor/src/messages/animation/animation_message_handler.rs

@@ -57,6 +57,7 @@ impl AnimationMessageHandler {
 	}
 }
 
+#[message_handler_data]
 impl MessageHandler<AnimationMessage, ()> for AnimationMessageHandler {
 	fn process_message(&mut self, message: AnimationMessage, responses: &mut VecDeque<Message>, _data: ()) {
 		match message {

editor/src/messages/broadcast/broadcast_message_handler.rs

@@ -5,6 +5,7 @@ pub struct BroadcastMessageHandler {
 	listeners: HashMap<BroadcastEvent, Vec<Message>>,
 }
 
+#[message_handler_data]
 impl MessageHandler<BroadcastMessage, ()> for BroadcastMessageHandler {
 	fn process_message(&mut self, message: BroadcastMessage, responses: &mut VecDeque<Message>, _data: ()) {
 		match message {

editor/src/messages/debug/debug_message_handler.rs

@@ -6,6 +6,7 @@ pub struct DebugMessageHandler {
 	pub message_logging_verbosity: MessageLoggingVerbosity,
 }
 
+#[message_handler_data]
 impl MessageHandler<DebugMessage, ()> for DebugMessageHandler {
 	fn process_message(&mut self, message: DebugMessage, responses: &mut VecDeque<Message>, _data: ()) {
 		match message {

editor/src/messages/debug/utility_types.rs

@@ -6,16 +6,35 @@ pub enum MessageLoggingVerbosity {
 	Contents,
 }
 
+#[derive(Debug)]
+pub struct MessageData {
+	name: String,
+	fields: Vec<String>,
+}
+
+impl MessageData {
+	pub fn name(&self) -> &str {
+		&self.name
+	}
+
+	pub fn fields(&self) -> &Vec<String> {
+		&self.fields
+	}
+}
+
+#[derive(Debug)]
 pub struct DebugMessageTree {
 	name: String,
 	variants: Option<Vec<DebugMessageTree>>,
+	data: Option<MessageData>,
 }
 
 impl DebugMessageTree {
 	pub fn new(name: &str) -> DebugMessageTree {
 		DebugMessageTree {
 			name: name.to_string(),
 			variants: None,
+			data: None,
 		}
 	}
 
@@ -27,11 +46,19 @@ impl DebugMessageTree {
 		}
 	}
 
+	pub fn add_data_field(&mut self, name: String, fields: Vec<String>) {
+		self.data = Some(MessageData { name, fields });
+	}
+
 	pub fn name(&self) -> &str {
 		&self.name
 	}
 
 	pub fn variants(&self) -> Option<&Vec<DebugMessageTree>> {
 		self.variants.as_ref()
 	}
+
+	pub fn data_fields(&self) -> Option<&MessageData> {
+		self.data.as_ref()
+	}
 }

editor/src/messages/dialog/dialog_message_handler.rs

@@ -16,6 +16,7 @@ pub struct DialogMessageHandler {
 	preferences_dialog: PreferencesDialogMessageHandler,
 }
 
+#[message_handler_data]
 impl MessageHandler<DialogMessage, DialogMessageData<'_>> for DialogMessageHandler {
 	fn process_message(&mut self, message: DialogMessage, responses: &mut VecDeque<Message>, data: DialogMessageData) {
 		let DialogMessageData { portfolio, preferences } = data;

editor/src/messages/dialog/export_dialog/export_dialog_message_handler.rs

@@ -32,6 +32,7 @@ impl Default for ExportDialogMessageHandler {
 	}
 }
 
+#[message_handler_data]
 impl MessageHandler<ExportDialogMessage, ExportDialogMessageData<'_>> for ExportDialogMessageHandler {
 	fn process_message(&mut self, message: ExportDialogMessage, responses: &mut VecDeque<Message>, data: ExportDialogMessageData) {
 		let ExportDialogMessageData { portfolio } = data;

editor/src/messages/dialog/new_document_dialog/new_document_dialog_message_handler.rs

@@ -11,6 +11,7 @@ pub struct NewDocumentDialogMessageHandler {
 	pub dimensions: UVec2,
 }
 
+#[message_handler_data]
 impl MessageHandler<NewDocumentDialogMessage, ()> for NewDocumentDialogMessageHandler {
 	fn process_message(&mut self, message: NewDocumentDialogMessage, responses: &mut VecDeque<Message>, _data: ()) {
 		match message {

editor/src/messages/dialog/preferences_dialog/preferences_dialog_message_handler.rs

@@ -13,6 +13,7 @@ pub struct PreferencesDialogMessageData<'a> {
 #[derive(Debug, Clone, Default)]
 pub struct PreferencesDialogMessageHandler {}
 
+#[message_handler_data]
 impl MessageHandler<PreferencesDialogMessage, PreferencesDialogMessageData<'_>> for PreferencesDialogMessageHandler {
 	fn process_message(&mut self, message: PreferencesDialogMessage, responses: &mut VecDeque<Message>, data: PreferencesDialogMessageData) {
 		let PreferencesDialogMessageData { preferences } = data;

editor/src/messages/globals/globals_message_handler.rs

@@ -3,6 +3,7 @@ use crate::messages::prelude::*;
 #[derive(Debug, Default)]
 pub struct GlobalsMessageHandler {}
 
+#[message_handler_data]
 impl MessageHandler<GlobalsMessage, ()> for GlobalsMessageHandler {
 	fn process_message(&mut self, message: GlobalsMessage, _responses: &mut VecDeque<Message>, _data: ()) {
 		match message {

editor/src/messages/input_mapper/input_mapper_message_handler.rs

@@ -16,6 +16,7 @@ pub struct InputMapperMessageHandler {
 	mapping: Mapping,
 }
 
+#[message_handler_data]
 impl MessageHandler<InputMapperMessage, InputMapperMessageData<'_>> for InputMapperMessageHandler {
 	fn process_message(&mut self, message: InputMapperMessage, responses: &mut VecDeque<Message>, data: InputMapperMessageData) {
 		let InputMapperMessageData { input, actions } = data;

editor/src/messages/input_mapper/key_mapping/key_mapping_message_handler.rs

@@ -13,6 +13,7 @@ pub struct KeyMappingMessageHandler {
 	mapping_handler: InputMapperMessageHandler,
 }
 
+#[message_handler_data]
 impl MessageHandler<KeyMappingMessage, KeyMappingMessageData<'_>> for KeyMappingMessageHandler {
 	fn process_message(&mut self, message: KeyMappingMessage, responses: &mut VecDeque<Message>, data: KeyMappingMessageData) {
 		let KeyMappingMessageData { input, actions } = data;

editor/src/messages/input_preprocessor/input_preprocessor_message_handler.rs

@@ -20,6 +20,7 @@ pub struct InputPreprocessorMessageHandler {
 	pub viewport_bounds: ViewportBounds,
 }
 
+#[message_handler_data]
 impl MessageHandler<InputPreprocessorMessage, InputPreprocessorMessageData> for InputPreprocessorMessageHandler {
 	fn process_message(&mut self, message: InputPreprocessorMessage, responses: &mut VecDeque<Message>, data: InputPreprocessorMessageData) {
 		let InputPreprocessorMessageData { keyboard_platform } = data;

editor/src/messages/layout/layout_message_handler.rs

@@ -338,6 +338,7 @@ impl LayoutMessageHandler {
 	}
 }
 
+#[message_handler_data(CustomData)]
 impl<F: Fn(&MessageDiscriminant) -> Vec<KeysGroup>> MessageHandler<LayoutMessage, F> for LayoutMessageHandler {
 	fn process_message(&mut self, message: LayoutMessage, responses: &mut std::collections::VecDeque<Message>, action_input_mapping: F) {
 		match message {
@@ -438,3 +439,7 @@ impl LayoutMessageHandler {
 		responses.add(message);
 	}
 }
+
+pub fn custom_data() -> Vec<String> {
+	vec![String::from("Fn(&MessageDiscriminant) -> Vec<KeysGroup>")]
+}

editor/src/messages/message.rs

@@ -64,11 +64,18 @@ mod test {
 
 	fn print_tree_node(tree: &DebugMessageTree, prefix: &str, is_last: bool) {
 		// Print the current node
-		let branch = if is_last { "└── " } else { "├── " };
-		println!("{}{}{}", prefix, branch, tree.name());
+		let (branch, child_prefix) = match &tree.data_fields() {
+			Some(_) => ("├── ", format!("{}│   ", prefix)),
+			None => {
+				if is_last {
+					("└── ", format!("{}    ", prefix))
+				} else {
+					("├── ", format!("{}│   ", prefix))
+				}
+			}
+		};
 
-		// Prepare prefix for children
-		let child_prefix = if is_last { format!("{}    ", prefix) } else { format!("{}│   ", prefix) };
+		println!("{}{}{}", prefix, branch, tree.name());
 
 		// Print children if any
 		if let Some(variants) = tree.variants() {
@@ -78,5 +85,16 @@ mod test {
 				print_tree_node(variant, &child_prefix, is_last_child);
 			}
 		}
+
+		// Print data field if any
+		if let Some(data) = tree.data_fields() {
+			let len = data.fields().len();
+			println!("{}{}{}", prefix, "└── ", data.name());
+			for (i, field) in data.fields().iter().enumerate() {
+				let is_last_field = i == len - 1;
+				let branch = if is_last_field { "└── " } else { "├── " };
+				println!("{}{}{}", format!("{}    ", prefix), branch, field);
+			}
+		}
 	}
 }

editor/src/messages/portfolio/document/document_message_handler.rs

@@ -166,6 +166,7 @@ impl Default for DocumentMessageHandler {
 	}
 }
 
+#[message_handler_data]
 impl MessageHandler<DocumentMessage, DocumentMessageData<'_>> for DocumentMessageHandler {
 	fn process_message(&mut self, message: DocumentMessage, responses: &mut VecDeque<Message>, data: DocumentMessageData) {
 		let DocumentMessageData {

editor/src/messages/portfolio/document/graph_operation/graph_operation_message_handler.rs

@@ -32,6 +32,7 @@ pub struct GraphOperationMessageHandler {}
 
 // GraphOperationMessageHandler always modified the document network. This is so changes to the layers panel will only affect the document network.
 // For changes to the selected network, use NodeGraphMessageHandler. No NodeGraphMessage's should be added here, since they will affect the selected nested network.
+#[message_handler_data]
 impl MessageHandler<GraphOperationMessage, GraphOperationMessageData<'_>> for GraphOperationMessageHandler {
 	fn process_message(&mut self, message: GraphOperationMessage, responses: &mut VecDeque<Message>, data: GraphOperationMessageData) {
 		let network_interface = data.network_interface;

editor/src/messages/portfolio/document/navigation/navigation_message_handler.rs

@@ -32,6 +32,7 @@ pub struct NavigationMessageHandler {
 	abortable_pan_start: Option<f64>,
 }
 
+#[message_handler_data]
 impl MessageHandler<NavigationMessage, NavigationMessageData<'_>> for NavigationMessageHandler {
 	fn process_message(&mut self, message: NavigationMessage, responses: &mut VecDeque<Message>, data: NavigationMessageData) {
 		let NavigationMessageData {

editor/src/messages/portfolio/document/node_graph/node_graph_message_handler.rs

@@ -84,6 +84,7 @@ pub struct NodeGraphMessageHandler {
 }
 
 /// NodeGraphMessageHandler always modifies the network which the selected nodes are in. No GraphOperationMessages should be added here, since those messages will always affect the document network.
+#[message_handler_data]
 impl<'a> MessageHandler<NodeGraphMessage, NodeGraphHandlerData<'a>> for NodeGraphMessageHandler {
 	fn process_message(&mut self, message: NodeGraphMessage, responses: &mut VecDeque<Message>, data: NodeGraphHandlerData<'a>) {
 		let NodeGraphHandlerData {

editor/src/messages/portfolio/document/overlays/overlays_message_handler.rs

@@ -17,6 +17,7 @@ pub struct OverlaysMessageHandler {
 	context: Option<web_sys::CanvasRenderingContext2d>,
 }
 
+#[message_handler_data]
 impl MessageHandler<OverlaysMessage, OverlaysMessageData<'_>> for OverlaysMessageHandler {
 	fn process_message(&mut self, message: OverlaysMessage, responses: &mut VecDeque<Message>, data: OverlaysMessageData) {
 		let OverlaysMessageData { overlays_visible, ipp, .. } = data;

editor/src/messages/portfolio/document/properties_panel/properties_panel_message_handler.rs

@@ -7,6 +7,7 @@ use crate::messages::prelude::*;
 #[derive(Debug, Clone, Default)]
 pub struct PropertiesPanelMessageHandler {}
 
+#[message_handler_data]
 impl MessageHandler<PropertiesPanelMessage, (&PersistentData, PropertiesPanelMessageHandlerData<'_>)> for PropertiesPanelMessageHandler {
 	fn process_message(&mut self, message: PropertiesPanelMessage, responses: &mut VecDeque<Message>, (persistent_data, data): (&PersistentData, PropertiesPanelMessageHandlerData)) {
 		let PropertiesPanelMessageHandlerData {

editor/src/messages/portfolio/menu_bar/menu_bar_message_handler.rs

@@ -19,6 +19,7 @@ pub struct MenuBarMessageHandler {
 	pub reset_node_definitions_on_open: bool,
 }
 
+#[message_handler_data]
 impl MessageHandler<MenuBarMessage, ()> for MenuBarMessageHandler {
 	fn process_message(&mut self, message: MenuBarMessage, responses: &mut VecDeque<Message>, _data: ()) {
 		match message {

editor/src/messages/portfolio/portfolio_message_handler.rs

@@ -54,6 +54,7 @@ pub struct PortfolioMessageHandler {
 	pub reset_node_definitions_on_open: bool,
 }
 
+#[message_handler_data]
 impl MessageHandler<PortfolioMessage, PortfolioMessageData<'_>> for PortfolioMessageHandler {
 	fn process_message(&mut self, message: PortfolioMessage, responses: &mut VecDeque<Message>, data: PortfolioMessageData) {
 		let PortfolioMessageData {

editor/src/messages/portfolio/spreadsheet/spreadsheet_message_handler.rs

@@ -23,6 +23,7 @@ pub struct SpreadsheetMessageHandler {
 	viewing_vector_data_domain: VectorDataDomain,
 }
 
+#[message_handler_data]
 impl MessageHandler<SpreadsheetMessage, ()> for SpreadsheetMessageHandler {
 	fn process_message(&mut self, message: SpreadsheetMessage, responses: &mut VecDeque<Message>, _data: ()) {
 		match message {

editor/src/messages/preferences/preferences_message_handler.rs

@@ -49,6 +49,7 @@ impl Default for PreferencesMessageHandler {
 	}
 }
 
+#[message_handler_data]
 impl MessageHandler<PreferencesMessage, ()> for PreferencesMessageHandler {
 	fn process_message(&mut self, message: PreferencesMessage, responses: &mut VecDeque<Message>, _data: ()) {
 		match message {

editor/src/messages/tool/tool_message_handler.rs

@@ -29,6 +29,7 @@ pub struct ToolMessageHandler {
 	pub tool_is_active: bool,
 }
 
+#[message_handler_data]
 impl MessageHandler<ToolMessage, ToolMessageData<'_>> for ToolMessageHandler {
 	fn process_message(&mut self, message: ToolMessage, responses: &mut VecDeque<Message>, data: ToolMessageData) {
 		let ToolMessageData {
@@ -327,13 +328,3 @@ impl MessageHandler<ToolMessage, ToolMessageData<'_>> for ToolMessageHandler {
 		list
 	}
 }
-
-#[cfg(test)]
-mod test {
-	use super::*;
-
-	#[test]
-	fn print_field() {
-		ToolMessageData::print_field_types();
-	}
-}

editor/src/messages/tool/transform_layer/transform_layer_message_handler.rs

@@ -134,6 +134,8 @@ fn update_colinear_handles(selected_layers: &[LayerNodeIdentifier], document: &D
 }
 
 type TransformData<'a> = (&'a DocumentMessageHandler, &'a InputPreprocessorMessageHandler, &'a ToolData, &'a mut ShapeState);
+
+#[message_handler_data(CustomData)]
 impl MessageHandler<TransformLayerMessage, TransformData<'_>> for TransformLayerMessageHandler {
 	fn process_message(&mut self, message: TransformLayerMessage, responses: &mut VecDeque<Message>, (document, input, tool_data, shape_editor): TransformData) {
 		let using_path_tool = tool_data.active_tool_type == ToolType::Path;
@@ -711,6 +713,15 @@ impl MessageHandler<TransformLayerMessage, TransformData<'_>> for TransformLayer
 	}
 }
 
+pub fn custom_data() -> Vec<String> {
+	vec![
+		String::from("&'a DocumentMessageHandler"),
+		String::from("&'a InputPreprocessorMessageHandler"),
+		String::from("&'a ToolData"),
+		String::from("&'a mut ShapeState"),
+	]
+}
+
 #[cfg(test)]
 mod test_transform_layer {
 	use crate::messages::portfolio::document::graph_operation::{transform_utils, utility_types::ModifyInputsContext};

editor/src/messages/workspace/workspace_message_handler.rs

@@ -5,6 +5,7 @@ pub struct WorkspaceMessageHandler {
 	node_graph_visible: bool,
 }
 
+#[message_handler_data]
 impl MessageHandler<WorkspaceMessage, ()> for WorkspaceMessageHandler {
 	fn process_message(&mut self, message: WorkspaceMessage, _responses: &mut VecDeque<Message>, _data: ()) {
 		match message {

editor/src/utility_traits.rs

@@ -48,4 +48,8 @@ pub trait Hint {
 
 pub trait HierarchicalTree {
 	fn build_message_tree() -> DebugMessageTree;
+
+	fn message_handler_data_str() -> Vec<String> {
+		Vec::new()
+	}
 }

proc-macros/src/hierarchical_tree.rs

@@ -51,6 +51,10 @@ pub fn generate_hierarchical_tree(input: TokenStream) -> syn::Result<TokenStream
 			fn build_message_tree() -> DebugMessageTree {
 				let mut message_tree = DebugMessageTree::new(stringify!(#input_type));
 				#(#build_message_tree)*
+				let data_str = #input_type::message_handler_data_str();
+				if data_str.len() > 0 {
+					message_tree.add_data_field(format!("{}Data", stringify!(#input_type)), data_str);
+				}
 				message_tree
 			}
 		}

proc-macros/src/lib.rs

@@ -8,6 +8,7 @@ mod helper_structs;
 mod helpers;
 mod hierarchical_tree;
 mod hint;
+mod message_handler_data_attr;
 mod transitive_child;
 mod widget_builder;
 
@@ -16,10 +17,11 @@ use crate::combined_message_attrs::combined_message_attrs_impl;
 use crate::discriminant::derive_discriminant_impl;
 use crate::extract_fields::derive_extract_field_impl;
 use crate::helper_structs::AttrInnerSingleString;
+use crate::hierarchical_tree::generate_hierarchical_tree;
 use crate::hint::derive_hint_impl;
+use crate::message_handler_data_attr::message_handler_data_attr_impl;
 use crate::transitive_child::derive_transitive_child_impl;
 use crate::widget_builder::derive_widget_builder_impl;
-use hierarchical_tree::generate_hierarchical_tree;
 use proc_macro::TokenStream;
 
 /// Derive the `ToDiscriminant` trait and create a `<Type Name>Discriminant` enum
@@ -295,6 +297,11 @@ pub fn derive_extract_field(input_item: TokenStream) -> TokenStream {
 	TokenStream::from(derive_extract_field_impl(input_item.into()).unwrap_or_else(|err| err.to_compile_error()))
 }
 
+#[proc_macro_attribute]
+pub fn message_handler_data(attr: TokenStream, input_item: TokenStream) -> TokenStream {
+	TokenStream::from(message_handler_data_attr_impl(attr.into(), input_item.into()).unwrap_or_else(|err| err.to_compile_error()))
+}
+
 #[cfg(test)]
 mod tests {
 	use super::*;