add mesh __str__ and __repr__ support

lib/iris/experimental/ugrid.py

@@ -13,6 +13,7 @@
 from abc import ABC, abstractmethod
 from collections import Iterable, namedtuple
 from functools import wraps
+import re
 
 import dask.array as da
 import numpy as np
@@ -49,6 +50,12 @@
 ]
 
 
+#: Numpy "threshold" printoptions default argument.
+NP_PRINTOPTIONS_THRESHOLD = 10
+#: Numpy "edgeitems" printoptions default argument.
+NP_PRINTOPTIONS_EDGEITEMS = 2
+
+
 # Configure the logger.
 logger = get_logger(__name__, fmt="[%(cls)s.%(funcName)s]")
 
@@ -204,6 +211,58 @@ def validate_arg_vs_list(arg_name, arg, valid_list):
             attributes=attributes,
         )
 
+    def __repr__(self):
+        def kwargs_filter(k, v):
+            result = False
+            if k != "cf_role":
+                if v is not None:
+                    result = True
+                    if (
+                        not isinstance(v, str)
+                        and isinstance(v, Iterable)
+                        and not v
+                    ):
+                        result = False
+                    elif k == "units" and v == "unknown":
+                        result = False
+            return result
+
+        def array2repr(array):
+            if self.has_lazy_indices():
+                result = repr(array)
+            else:
+                with np.printoptions(
+                    threshold=NP_PRINTOPTIONS_THRESHOLD,
+                    edgeitems=NP_PRINTOPTIONS_EDGEITEMS,
+                ):
+                    result = re.sub("\n  *", " ", repr(array))
+            return result
+
+        # positional arguments
+        args = ", ".join(
+            [
+                f"{array2repr(self.core_indices())}",
+                f"cf_role={self.cf_role!r}",
+            ]
+        )
+
+        # optional arguments (metadata)
+        kwargs = ", ".join(
+            [
+                f"{k}={v!r}"
+                for k, v in self.metadata._asdict().items()
+                if kwargs_filter(k, v)
+            ]
+        )
+
+        return f"{self.__class__.__name__}({', '.join([args, kwargs])})"
+
+    def __str__(self):
+        args = ", ".join(
+            [f"cf_role={self.cf_role!r}", f"start_index={self.start_index!r}"]
+        )
+        return f"{self.__class__.__name__}({args})"
+
     @property
     def _values(self):
         # Overridden just to allow .setter override.
@@ -832,13 +891,13 @@ def __init__(
         topology_dimension,
         node_coords_and_axes,
         connectivities,
+        edge_coords_and_axes=None,
+        face_coords_and_axes=None,
         standard_name=None,
         long_name=None,
         var_name=None,
         units=None,
         attributes=None,
-        edge_coords_and_axes=None,
-        face_coords_and_axes=None,
         node_dimension=None,
         edge_dimension=None,
         face_dimension=None,
@@ -932,8 +991,75 @@ def __ne__(self, other):
         return NotImplemented
 
     def __repr__(self):
-        # TBD
-        args = []
+        def to_coord_and_axis(members):
+            def axis(member):
+                return member.split("_")[1]
+
+            result = [
+                f"({coord!s}, {axis(member)!r})"
+                for member, coord in members._asdict().items()
+                if coord is not None
+            ]
+            result = f"[{', '.join(result)}]" if result else None
+            return result
+
+        node_coords_and_axes = to_coord_and_axis(self.node_coords)
+        connectivities = [
+            str(connectivity)
+            for connectivity in self.all_connectivities
+            if connectivity is not None
+        ]
+
+        if len(connectivities) == 1:
+            connectivities = connectivities[0]
+        else:
+            connectivities = f"[{', '.join(connectivities)}]"
+
+        # positional arguments
+        args = [
+            f"topology_dimension={self.topology_dimension!r}",
+            f"node_coords_and_axes={node_coords_and_axes}",
+            f"connectivities={connectivities}",
+        ]
+
+        # optional argument
+        edge_coords_and_axes = to_coord_and_axis(self.edge_coords)
+        if edge_coords_and_axes:
+            args.append(f"edge_coords_and_axes={edge_coords_and_axes}")
+
+        # optional argument
+        if self.topology_dimension > 1:
+            face_coords_and_axes = to_coord_and_axis(self.face_coords)
+            if face_coords_and_axes:
+                args.append(f"face_coords_and_axes={face_coords_and_axes}")
+
+        def kwargs_filter(k, v):
+            result = False
+            if k != "topology_dimension":
+                if not (
+                    self.topology_dimension == 1 and k == "face_dimension"
+                ):
+                    if v is not None:
+                        result = True
+                        if (
+                            not isinstance(v, str)
+                            and isinstance(v, Iterable)
+                            and not v
+                        ):
+                            result = False
+                        elif k == "units" and v == "unknown":
+                            result = False
+            return result
+
+        # optional arguments (metadata)
+        args.extend(
+            [
+                f"{k}={v!r}"
+                for k, v in self.metadata._asdict().items()
+                if kwargs_filter(k, v)
+            ]
+        )
+
         return f"{self.__class__.__name__}({', '.join(args)})"
 
     def __setstate__(self, state):
@@ -942,11 +1068,6 @@ def __setstate__(self, state):
         self._coord_manager = coord_manager
         self._connectivity_manager = connectivity_manager
 
-    def __str__(self):
-        # TBD
-        args = []
-        return f"{self.__class__.__name__}({', '.join(args)})"
-
     def _set_dimension_names(self, node, edge, face, reset=False):
         args = (node, edge, face)
         currents = (
@@ -1330,9 +1451,7 @@ def __setstate__(self, state):
         self._members = state
 
     def __str__(self):
-        args = [
-            f"{member}=True" for member, coord in self if coord is not None
-        ]
+        args = [f"{member}" for member, coord in self if coord is not None]
         return f"{self.__class__.__name__}({', '.join(args)})"
 
     def _remove(self, **kwargs):
@@ -1733,7 +1852,7 @@ def __setstate__(self, state):
 
     def __str__(self):
         args = [
-            f"{member}=True"
+            f"{member}"
             for member, connectivity in self
             if connectivity is not None
         ]

lib/iris/tests/unit/experimental/ugrid/test_Connectivity.py

@@ -96,19 +96,16 @@ def test_src_lengths(self):
 
     def test___str__(self):
         expected = (
-            "Connectivity(array([[1, 2, 3],\n       [4, 5, 6],\n       [7, 8, 9]]), "
-            "standard_name=None, units=Unit('unknown'), "
-            "long_name='my_face_nodes', var_name='face_nodes', "
-            "attributes={'notes': 'this is a test'})"
+            "Connectivity(cf_role='face_node_connectivity', start_index=1)"
         )
         self.assertEqual(expected, self.connectivity.__str__())
 
     def test___repr__(self):
         expected = (
-            "Connectivity(array([[1, 2, 3],\n       [4, 5, 6],\n       [7, 8, 9]]), "
-            "standard_name=None, units=Unit('unknown'), "
-            "long_name='my_face_nodes', var_name='face_nodes', "
-            "attributes={'notes': 'this is a test'})"
+            "Connectivity(array([[1, 2, 3], [4, 5, 6], [7, 8, 9]]), "
+            "cf_role='face_node_connectivity', long_name='my_face_nodes', "
+            "var_name='face_nodes', attributes={'notes': 'this is a test'}, "
+            "start_index=1, src_dim=1)"
         )
         self.assertEqual(expected, self.connectivity.__repr__())