refactor(hugr-py): move dfg to own file

hugr-py/src/hugr/_dfg.py

@@ -0,0 +1,78 @@
+from __future__ import annotations
+from dataclasses import dataclass
+from typing import Sequence, Iterable
+from ._hugr import Hugr, Node, Wire, OutPort
+
+from ._ops import Op, Command, Input, Output, DFG
+from hugr.serialization.tys import FunctionType, Type
+
+
+@dataclass()
+class Dfg:
+    hugr: Hugr
+    root: Node
+    input_node: Node
+    output_node: Node
+
+    def __init__(
+        self, input_types: Sequence[Type], output_types: Sequence[Type]
+    ) -> None:
+        input_types = list(input_types)
+        output_types = list(output_types)
+        root_op = DFG(FunctionType(input=input_types, output=output_types))
+        self.hugr = Hugr(root_op)
+        self.root = self.hugr.root
+        self.input_node = self.hugr.add_node(
+            Input(input_types), self.root, len(input_types)
+        )
+        self.output_node = self.hugr.add_node(Output(output_types), self.root)
+
+    @classmethod
+    def endo(cls, types: Sequence[Type]) -> Dfg:
+        return Dfg(types, types)
+
+    def _input_op(self) -> Input:
+        dop = self.hugr[self.input_node].op
+        assert isinstance(dop, Input)
+        return dop
+
+    def inputs(self) -> list[OutPort]:
+        return [self.input_node.out(i) for i in range(len(self._input_op().types))]
+
+    def add_op(self, op: Op, /, *args: Wire, num_outs: int | None = None) -> Node:
+        new_n = self.hugr.add_node(op, self.root, num_outs=num_outs)
+        self._wire_up(new_n, args)
+        return new_n
+
+    def add(self, com: Command) -> Node:
+        return self.add_op(com.op, *com.incoming, num_outs=com.op.num_out)
+
+    def insert_nested(self, dfg: Dfg, *args: Wire) -> Node:
+        mapping = self.hugr.insert_hugr(dfg.hugr, self.root)
+        self._wire_up(mapping[dfg.root], args)
+        return mapping[dfg.root]
+
+    def add_nested(
+        self,
+        input_types: Sequence[Type],
+        output_types: Sequence[Type],
+        *args: Wire,
+    ) -> Dfg:
+        dfg = self.hugr.add_dfg(input_types, output_types)
+        self._wire_up(dfg.root, args)
+        return dfg
+
+    def set_outputs(self, *args: Wire) -> None:
+        self._wire_up(self.output_node, args)
+
+    def add_state_order(self, src: Node, dst: Node) -> None:
+        # adds edge to the right of all existing edges
+        # breaks if further edges are added
+        self.hugr.add_link(
+            src.out(self.hugr.num_outgoing(src)), dst.inp(self.hugr.num_incoming(dst))
+        )
+
+    def _wire_up(self, node: Node, ports: Iterable[Wire]):
+        for i, p in enumerate(ports):
+            src = p.out_port()
+            self.hugr.add_link(src, node.inp(i))

hugr-py/src/hugr/_hugr.py

@@ -12,16 +12,20 @@
     cast,
     overload,
     ClassVar,
+    TYPE_CHECKING,
 )
 
 from typing_extensions import Self
 
 from hugr.serialization.serial_hugr import SerialHugr
 from hugr.serialization.ops import OpType as SerialOp
-from hugr.serialization.tys import Type, FunctionType
-from hugr._ops import Op, Input, Output, DFG, Command
+from hugr.serialization.tys import Type
+from hugr._ops import Op
 from hugr.utils import BiMap
 
+if TYPE_CHECKING:
+    from ._dfg import Dfg
+
 
 class Direction(Enum):
     INCOMING = 0
@@ -304,6 +308,8 @@ def insert_hugr(self, hugr: Hugr, parent: Node | None = None) -> dict[Node, Node
         return mapping
 
     def add_dfg(self, input_types: Sequence[Type], output_types: Sequence[Type]) -> Dfg:
+        from ._dfg import Dfg
+
         dfg = Dfg(input_types, output_types)
         mapping = self.insert_hugr(dfg.hugr, self.root)
         dfg.hugr = self
@@ -352,74 +358,3 @@ def from_serial(cls, serial: SerialHugr) -> Hugr:
             )
 
         return hugr
-
-
-@dataclass()
-class Dfg:
-    hugr: Hugr
-    root: Node
-    input_node: Node
-    output_node: Node
-
-    def __init__(
-        self, input_types: Sequence[Type], output_types: Sequence[Type]
-    ) -> None:
-        input_types = list(input_types)
-        output_types = list(output_types)
-        root_op = DFG(FunctionType(input=input_types, output=output_types))
-        self.hugr = Hugr(root_op)
-        self.root = self.hugr.root
-        self.input_node = self.hugr.add_node(
-            Input(input_types), self.root, len(input_types)
-        )
-        self.output_node = self.hugr.add_node(Output(output_types), self.root)
-
-    @classmethod
-    def endo(cls, types: Sequence[Type]) -> Dfg:
-        return Dfg(types, types)
-
-    def _input_op(self) -> Input:
-        dop = self.hugr[self.input_node].op
-        assert isinstance(dop, Input)
-        return dop
-
-    def inputs(self) -> list[OutPort]:
-        return [self.input_node.out(i) for i in range(len(self._input_op().types))]
-
-    def add_op(self, op: Op, /, *args: Wire, num_outs: int | None = None) -> Node:
-        new_n = self.hugr.add_node(op, self.root, num_outs=num_outs)
-        self._wire_up(new_n, args)
-        return new_n
-
-    def add(self, com: Command) -> Node:
-        return self.add_op(com.op, *com.incoming, num_outs=com.op.num_out)
-
-    def insert_nested(self, dfg: Dfg, *args: Wire) -> Node:
-        mapping = self.hugr.insert_hugr(dfg.hugr, self.root)
-        self._wire_up(mapping[dfg.root], args)
-        return mapping[dfg.root]
-
-    def add_nested(
-        self,
-        input_types: Sequence[Type],
-        output_types: Sequence[Type],
-        *args: Wire,
-    ) -> Dfg:
-        dfg = self.hugr.add_dfg(input_types, output_types)
-        self._wire_up(dfg.root, args)
-        return dfg
-
-    def set_outputs(self, *args: Wire) -> None:
-        self._wire_up(self.output_node, args)
-
-    def add_state_order(self, src: Node, dst: Node) -> None:
-        # adds edge to the right of all existing edges
-        # breaks if further edges are added
-        self.hugr.add_link(
-            src.out(self.hugr.num_outgoing(src)), dst.inp(self.hugr.num_incoming(dst))
-        )
-
-    def _wire_up(self, node: Node, ports: Iterable[Wire]):
-        for i, p in enumerate(ports):
-            src = p.out_port()
-            self.hugr.add_link(src, node.inp(i))

hugr-py/tests/test_hugr_build.py

@@ -3,7 +3,8 @@
 import subprocess
 import os
 import pathlib
-from hugr._hugr import Dfg, Hugr, Node, Wire
+from hugr._hugr import Hugr, Node, Wire
+from hugr._dfg import Dfg
 from hugr._ops import Custom, Command
 import hugr._ops as ops
 from hugr.serialization import SerialHugr