feat: Default more builder methods to open extension sets (#492)

Another step towards #424 (but not all the way there yet)

Author: croyzor

src/builder.rs

@@ -135,7 +135,8 @@ pub(crate) mod test {
 
     /// A helper method which creates a DFG rooted hugr with closed resources,
     /// for tests which want to avoid having open extension variables after
-    /// inference.
+    /// inference. Using DFGBuilder will default to a root node with an open
+    /// extension variable
     pub(crate) fn closed_dfg_root_hugr(signature: FunctionType) -> Hugr {
         let mut hugr = Hugr::new(NodeType::pure(ops::DFG {
             signature: signature.clone(),

src/builder/build_traits.rs

@@ -322,8 +322,7 @@ pub trait Dataflow: Container {
 
         let (cfg_node, _) = add_node_with_wires(
             self,
-            // TODO: Make input extensions a parameter
-            NodeType::pure(ops::CFG {
+            NodeType::open_extensions(ops::CFG {
                 inputs: inputs.clone(),
                 outputs: output_types.clone(),
             }),
@@ -606,8 +605,7 @@ fn add_op_with_wires<T: Dataflow + ?Sized>(
     optype: impl Into<OpType>,
     inputs: Vec<Wire>,
 ) -> Result<(Node, usize), BuildError> {
-    // TODO: Make this NodeType::open_extensions
-    add_node_with_wires(data_builder, NodeType::pure(optype), inputs)
+    add_node_with_wires(data_builder, NodeType::open_extensions(optype), inputs)
 }
 
 fn add_node_with_wires<T: Dataflow + ?Sized>(

src/builder/cfg.rs

@@ -63,7 +63,7 @@ impl CFGBuilder<Hugr> {
         };
 
         // TODO: Allow input extensions to be specified
-        let base = Hugr::new(NodeType::pure(cfg_op));
+        let base = Hugr::new(NodeType::open_extensions(cfg_op));
         let cfg_node = base.root();
         CFGBuilder::create(base, cfg_node, input, output)
     }
@@ -280,7 +280,7 @@ impl BlockBuilder<Hugr> {
         };
 
         // TODO: Allow input extensions to be specified
-        let base = Hugr::new(NodeType::pure(op));
+        let base = Hugr::new(NodeType::open_extensions(op));
         let root = base.root();
         Self::create(base, root, predicate_variants, other_outputs, inputs)
     }

src/builder/conditional.rs

@@ -129,7 +129,6 @@ impl<B: AsMut<Hugr> + AsRef<Hugr>> ConditionalBuilder<B> {
                 // TODO: Allow this to be non-pure
                 self.hugr_mut().add_op_before(sibling_node, case_op)?
             } else {
-                // TODO: Allow this to be non-pure
                 self.add_child_op(case_op)?
             };
 
@@ -178,7 +177,7 @@ impl ConditionalBuilder<Hugr> {
             extension_delta,
         };
         // TODO: Allow input extensions to be specified
-        let base = Hugr::new(NodeType::pure(op));
+        let base = Hugr::new(NodeType::open_extensions(op));
         let conditional_node = base.root();
 
         Ok(ConditionalBuilder {
@@ -196,8 +195,7 @@ impl CaseBuilder<Hugr> {
         let op = ops::Case {
             signature: signature.clone(),
         };
-        // TODO: Allow input extensions to be specified
-        let base = Hugr::new(NodeType::pure(op));
+        let base = Hugr::new(NodeType::open_extensions(op));
         let root = base.root();
         let dfg_builder = DFGBuilder::create_with_io(base, root, signature, None)?;
 

src/builder/dataflow.rs

@@ -76,6 +76,7 @@ impl<T: AsMut<Hugr> + AsRef<Hugr>> DFGBuilder<T> {
 
 impl DFGBuilder<Hugr> {
     /// Begin building a new DFG rooted HUGR.
+    /// Input extensions default to being an open variable
     ///
     /// # Errors
     ///
@@ -84,13 +85,9 @@ impl DFGBuilder<Hugr> {
         let dfg_op = ops::DFG {
             signature: signature.clone(),
         };
-        // TODO: Allow input extensions to be specified
-        let base = Hugr::new(NodeType::pure(dfg_op));
+        let base = Hugr::new(NodeType::open_extensions(dfg_op));
         let root = base.root();
-        DFGBuilder::create_with_io(
-            base, root, signature, // TODO: Make input extensions a parameter
-            None,
-        )
+        DFGBuilder::create_with_io(base, root, signature, None)
     }
 }
 
@@ -256,8 +253,7 @@ pub(crate) mod test {
 
                 let inner_builder = func_builder.dfg_builder(
                     FunctionType::new(type_row![NAT], type_row![NAT]),
-                    // TODO: This should be None
-                    Some(ExtensionSet::new()),
+                    None,
                     [int],
                 )?;
                 let inner_id = n_identity(inner_builder)?;

src/builder/tail_loop.rs

@@ -82,7 +82,7 @@ impl TailLoopBuilder<Hugr> {
             rest: inputs_outputs.into(),
         };
         // TODO: Allow input extensions to be specified
-        let base = Hugr::new(NodeType::pure(tail_loop.clone()));
+        let base = Hugr::new(NodeType::open_extensions(tail_loop.clone()));
         let root = base.root();
         Self::create_with_io(base, root, &tail_loop)
     }