feat: Non-region entrypoints in hugr-model.

hugr-core/src/export.rs

@@ -309,6 +309,7 @@ impl<'a> Context<'a> {
                     node,
                     model::ScopeClosure::Open,
                     false,
+                    false,
                 )]);
                 table::Operation::Dfg
             }
@@ -333,6 +334,7 @@ impl<'a> Context<'a> {
                     node,
                     model::ScopeClosure::Open,
                     false,
+                    false,
                 )]);
                 table::Operation::Block
             }
@@ -349,6 +351,7 @@ impl<'a> Context<'a> {
                     node,
                     model::ScopeClosure::Closed,
                     false,
+                    false,
                 )]);
                 table::Operation::DefineFunc(symbol)
             }),
@@ -462,6 +465,7 @@ impl<'a> Context<'a> {
                     node,
                     model::ScopeClosure::Open,
                     false,
+                    false,
                 )]);
                 table::Operation::TailLoop
             }
@@ -515,6 +519,7 @@ impl<'a> Context<'a> {
 
         self.export_node_json_metadata(node, &mut meta);
         self.export_node_order_metadata(node, &mut meta);
+        self.export_node_entrypoint_metadata(node, &mut meta);
         let meta = self.bump.alloc_slice_copy(&meta);
 
         self.module.nodes[node_id.index()] = table::Node {
@@ -613,6 +618,7 @@ impl<'a> Context<'a> {
         node: Node,
         closure: model::ScopeClosure,
         export_json_meta: bool,
+        export_entrypoint_meta: bool,
     ) -> table::RegionId {
         let region = self.module.insert_region(table::Region::default());
 
@@ -631,7 +637,9 @@ impl<'a> Context<'a> {
         if export_json_meta {
             self.export_node_json_metadata(node, &mut meta);
         }
-        self.export_node_entrypoint_metadata(node, &mut meta);
+        if export_entrypoint_meta {
+            self.export_node_entrypoint_metadata(node, &mut meta);
+        }
 
         let children = self.hugr.children(node);
         let mut region_children = BumpVec::with_capacity_in(children.size_hint().0 - 2, self.bump);
@@ -801,7 +809,7 @@ impl<'a> Context<'a> {
                 panic!("expected a `Case` node as a child of a `Conditional` node");
             };
 
-            regions.push(self.export_dfg(child, model::ScopeClosure::Open, true));
+            regions.push(self.export_dfg(child, model::ScopeClosure::Open, true, true));
         }
 
         regions.into_bump_slice()
@@ -1076,7 +1084,7 @@ impl<'a> Context<'a> {
 
                 let region = match hugr.entrypoint_optype() {
                     OpType::DFG(_) => {
-                        self.export_dfg(hugr.entrypoint(), model::ScopeClosure::Closed, true)
+                        self.export_dfg(hugr.entrypoint(), model::ScopeClosure::Closed, true, true)
                     }
                     _ => panic!("Value::Function root must be a DFG"),
                 };

hugr-core/tests/snapshots/model__roundtrip_entrypoint.snap

@@ -11,7 +11,8 @@ expression: ast
 (import core.entrypoint)
 
 (define-func public main (core.fn [] [])
-  (dfg (signature (core.fn [] [])) (meta core.entrypoint)))
+  (meta core.entrypoint)
+  (dfg (signature (core.fn [] []))))
 
 (mod)
 
@@ -20,7 +21,8 @@ expression: ast
 (import core.entrypoint)
 
 (define-func public wrapper_dfg (core.fn [] [])
-  (dfg (signature (core.fn [] [])) (meta core.entrypoint)))
+  (meta core.entrypoint)
+  (dfg (signature (core.fn [] []))))
 
 (mod)
 
@@ -39,6 +41,7 @@ expression: ast
     (signature (core.fn [] []))
     (cfg
       (signature (core.fn [] []))
+      (meta core.entrypoint)
       (cfg [%0] [%1]
         (signature (core.ctrl [[]] [[]]))
         (meta core.entrypoint)

hugr-py/src/hugr/model/export.py

@@ -75,6 +75,7 @@ def export_node(
 
         outputs = [self.link_name(OutPort(node, i)) for i in range(node_data._num_outs)]
         meta = self.export_json_meta(node)
+        meta += self.export_entrypoint_meta(node)
 
         # Add an order hint key to the node if necessary
         if _has_order_links(self.hugr, node):
@@ -123,7 +124,8 @@ def export_node(
 
             case Conditional() as op:
                 regions = [
-                    self.export_region_dfg(child) for child in node_data.children
+                    self.export_region_dfg(child, entrypoint_meta=True)
+                    for child in node_data.children
                 ]
 
                 signature = op.outer_signature().to_model()
@@ -424,16 +426,18 @@ def export_region_module(self, node: Node) -> model.Region:
 
         return model.Region(kind=model.RegionKind.MODULE, children=children, meta=meta)
 
-    def export_region_dfg(self, node: Node) -> model.Region:
+    def export_region_dfg(self, node: Node, entrypoint_meta=False) -> model.Region:
         """Export the children of a node as a dataflow region."""
         node_data = self.hugr[node]
         children: list[model.Node] = []
         source_types: model.Term = model.Wildcard()
         target_types: model.Term = model.Wildcard()
         sources = []
         targets = []
+        meta = []
 
-        meta = self.export_entrypoint_meta(node)
+        if entrypoint_meta:
+            meta += self.export_entrypoint_meta(node)
 
         for child in node_data.children:
             child_data = self.hugr[child]