Named topology reprs (#4701)

Adds repr to NamedTopology.

cirq-core/cirq/devices/named_topologies.py

@@ -19,9 +19,11 @@
 from typing import Dict, List, Tuple, Any, Sequence, Union, Iterable, TYPE_CHECKING
 
 import networkx as nx
+from matplotlib import pyplot as plt
+
+from cirq import _compat
 from cirq.devices import GridQubit, LineQubit
 from cirq.protocols.json_serialization import obj_to_dict_helper
-from matplotlib import pyplot as plt
 
 if TYPE_CHECKING:
     import cirq
@@ -137,6 +139,9 @@ def draw(self, ax=None, tilted: bool = True, **kwargs) -> Dict[Any, Tuple[int, i
     def _json_dict_(self) -> Dict[str, Any]:
         return dataclass_json_dict(self)
 
+    def __repr__(self) -> str:
+        return _compat.dataclass_repr(self)
+
 
 @dataclass(frozen=True)
 class TiltedSquareLattice(NamedTopology):
@@ -237,6 +242,9 @@ def nodes_to_gridqubits(self, offset=(0, 0)) -> Dict[Tuple[int, int], 'cirq.Grid
     def _json_dict_(self) -> Dict[str, Any]:
         return dataclass_json_dict(self)
 
+    def __repr__(self) -> str:
+        return _compat.dataclass_repr(self)
+
 
 def get_placements(
     big_graph: nx.Graph, small_graph: nx.Graph, max_placements=100_000

cirq-core/cirq/devices/named_topologies_test.py

@@ -36,6 +36,8 @@ def test_tilted_square_lattice(width, height):
     assert nx.is_connected(topo.graph)
     assert nx.algorithms.planarity.check_planarity(topo.graph)
 
+    cirq.testing.assert_equivalent_repr(topo)
+
 
 def test_bad_tilted_square_lattice():
     with pytest.raises(ValueError):
@@ -82,6 +84,8 @@ def test_line_topology():
     assert LineTopology(2).n_nodes == 2
     assert LineTopology(2).graph.number_of_nodes() == 2
 
+    cirq.testing.assert_equivalent_repr(topo)
+
 
 def test_line_topology_nodes_as_qubits():
     for n in range(2, 10, 2):