feat: Improve rendering of tags and cases

hugr-py/src/hugr/hugr/render.py

@@ -9,7 +9,7 @@
 from typing_extensions import assert_never
 
 from hugr.hugr import Hugr
-from hugr.ops import AsExtOp
+from hugr.ops import AsExtOp, Case
 from hugr.tys import CFKind, ConstKind, FunctionKind, Kind, OrderKind, ValueKind
 
 from .node_port import InPort, Node, OutPort
@@ -243,8 +243,22 @@ def _in_order_name(self, n: Node) -> str:
     def _out_order_name(self, n: Node) -> str:
         return f"{n.idx}:{self._OUTPUT_PREFIX}None"
 
-    def _viz_node(self, node: Node, hugr: Hugr, graph: Digraph) -> None:
-        """Render a (possibly nested) node to a graphviz graph."""
+    def _viz_node(
+        self,
+        node: Node,
+        hugr: Hugr,
+        graph: Digraph,
+        *,
+        sibling_order: int | None = None,
+    ) -> None:
+        """Render a (possibly nested) node to a graphviz graph.
+
+        Args:
+            node: The node to render.
+            hugr: The HUGR to render.
+            graph: The graphviz graph to render the node to.
+            sibling_order: The order of the node in the region's sibling list.
+        """
         meta = hugr[node].metadata
         if len(meta) > 0 and self.config.display_metadata:
             if self.config.max_metadata_length is not None:
@@ -278,6 +292,9 @@ def _viz_node(self, node: Node, hugr: Hugr, graph: Digraph) -> None:
         op = hugr[node].op
         if isinstance(op, AsExtOp) and not self.config.qualify_op_name:
             op_name = op.op_def().name
+        elif isinstance(op, Case) and sibling_order is not None:
+            # Indicate the case number
+            op_name = f"{op.name()}[{sibling_order}]"
         else:
             op_name = op.name()
 
@@ -311,8 +328,8 @@ def _viz_node(self, node: Node, hugr: Hugr, graph: Digraph) -> None:
 
         if hugr.children(node):
             with graph.subgraph(name=f"cluster{node.idx}") as sub:
-                for child in hugr.children(node):
-                    self._viz_node(child, hugr, sub)
+                for sibling_order, child in enumerate(hugr.children(node)):
+                    self._viz_node(child, hugr, sub, sibling_order=sibling_order)
                 html_label = self._format_html_label(**label_config)
                 sub.node(f"{node.idx}", shape="plain", label=f"<{html_label}>")
                 sub.attr(

hugr-py/src/hugr/ops.py

@@ -816,8 +816,18 @@ def __repr__(self) -> str:
     def __str__(self) -> str:
         if len(self.sum_ty.variant_rows) == 2:
             left, right = self.sum_ty.variant_rows
-            if len(left) == 0 and self.tag == 1:
-                return "Some"
+            if not left and not right:
+                # Boolean
+                if self.tag == 1:
+                    return "True"
+                else:
+                    return "False"
+            elif not left:
+                # Option
+                if self.tag == 1:
+                    return "Some"
+                else:
+                    return "None"
             elif self.tag == 0:
                 return "Left"
             else:

hugr-py/tests/__snapshots__/test_hugr_build.ambr

@@ -2593,7 +2593,7 @@
           <TD>
           <TABLE BORDER="0" CELLBORDER="0">
               <TR><TD><FONT POINT-SIZE="11.0" FACE="monospace"
-                  COLOR="black"><B>Case</B></FONT></TD></TR>
+                  COLOR="black"><B>Case[0]</B></FONT></TD></TR>
           </TABLE>
           </TD>
       </TR>
@@ -2661,7 +2661,7 @@
           <TD>
           <TABLE BORDER="0" CELLBORDER="0">
               <TR><TD><FONT POINT-SIZE="11.0" FACE="monospace"
-                  COLOR="black"><B>Case</B></FONT></TD></TR>
+                  COLOR="black"><B>Case[1]</B></FONT></TD></TR>
           </TABLE>
           </TD>
       </TR>

hugr-py/tests/test_ops.py

@@ -43,7 +43,10 @@
         (DivMod, "arithmetic.int.idivmod_u<5>"),
         (MakeTuple(), "MakeTuple"),
         (UnpackTuple(), "UnpackTuple"),
-        (Tag(0, Bool), "Left"),
+        (Tag(0, Bool), "False"),
+        (Tag(1, Bool), "True"),
+        (Tag(0, tys.Option(Bool)), "None"),
+        (Tag(1, tys.Option(Bool)), "Some"),
         (Tag(0, tys.Sum([[Bool, Bool, Bool]])), "Tag(0)"),
         (CFG([]), "CFG"),
         (DFG([]), "DFG"),

pyproject.toml

@@ -6,13 +6,14 @@ members = ["hugr-py"]
 
 dev-dependencies = [
     "pre-commit >=3.6.2,<4",
-    "pytest >=8.1.1,<9",
-    "pytest-cov >=5.0.0,<6",
+    "pytest ~=9.0",
+    "pytest-cov ~=7.0",
+    "pytest-xdist ~= 3.8",
     "maturin >=1.7.0,<2",
     "mypy >=1.9.0,<2",
     "ruff >=0.6.2,<0.7",
     "toml >=0.10.0,<0.11",
-    "syrupy >=4.7.1,<5",
+    "syrupy ~=5.1",
     "types-zstd >= 1.5.6.6",
     "pytket >= 1.34.0",
 ]
@@ -22,8 +23,6 @@ addopts = "--doctest-modules  --ignore=test_files"
 filterwarnings = "ignore::DeprecationWarning:lark.*"
 
 
-
-
 [tool.mypy]
 # TODO: Fix lints and enable this
 #strict = true