Better handle __repr__ (#39)

[wdeconinck]

This pull request tries to address #39 , by standardizing and improving the __repr__ string representations for many core classes, making debugging and interactive usage more informative and user-friendly. It also adds a new test to ensure that the __repr__ output for point classes is round-trip safe (i.e., objects can be reconstructed from their string representation).

Key changes include:

Improved and Standardized __repr__ Methods:

• Added or updated __repr__ implementations for numerous classes (e.g., Field, Mesh, StructuredMeshGenerator, IrregularConnectivity, BlockConnectivity, MultiBlockConnectivity, Nodes, HybridElements, FunctionSpace, EdgeColumns, NodeColumns, CellColumns, Topology, and Gmsh). These representations now follow a consistent, Pythonic format (e.g., <atlas4py.ClassName ...>), often including key attributes for easier inspection.

Testing Improvements:

• Added new tests to verify that the __repr__ methods return the expected strings for all major classes, including round-trip tests for point types and coverage for mesh/connectivity/function space objects.

Code Quality and Consistency:

• Ensured all classes now have a meaningful and consistent string representation, improving usability in interactive sessions and debugging.

[Copilot]

🟡 Changes recommended

Several representations reference the nonexistent atlas4py.mesh module, and most new outputs remain untested.

Once you've addressed the issues Copilot identified, you can request another Copilot review.

Pull request overview

Improves atlas4py object representations for clearer debugging and interactive use.

Changes:

• Standardizes representations across core bindings.
• Makes point representations round-trip safe.
• Adds parameterized point representation tests.

File summaries

File	Description
src/atlas4py/_atlas4py.cpp	Adds and updates binding representations.
tests/test_bindings.py	Tests point representation round trips.

Review details

Suppressed comments (7)

src/atlas4py/_atlas4py.cpp:387

• StructuredMeshGenerator is exported from the root package, and there is no atlas4py.mesh submodule. Use its actual public path so the new representation does not advertise a nonexistent symbol.

            return "<atlas4py.mesh.StructuredMeshGenerator>";

src/atlas4py/_atlas4py.cpp:414

• Both branches identify this root-level binding as atlas4py.mesh.IrregularConnectivity, but mesh is not a Python submodule. The representation should use the class's exported path, atlas4py.IrregularConnectivity.

        .def("__repr__", []( mesh::IrregularConnectivity const& c ) {

src/atlas4py/_atlas4py.cpp:433

• Both branches use the nonexistent path atlas4py.mesh.BlockConnectivity; this class is registered on the root module and exposed as atlas4py.BlockConnectivity.

        .def("__repr__", []( mesh::BlockConnectivity const& c ) {

src/atlas4py/_atlas4py.cpp:461

• The representation points to atlas4py.mesh.MultiBlockConnectivity, although no mesh Python submodule exists and this binding is exported at atlas4py.MultiBlockConnectivity.

        .def("__repr__", []( mesh::MultiBlockConnectivity const& c ) {

src/atlas4py/_atlas4py.cpp:481

• Nodes is a root-level Python binding, not a member of an atlas4py.mesh submodule. This should show atlas4py.Nodes to avoid reporting a nonexistent public path.

            oss << "<atlas4py.mesh.Nodes size=" << n.size() << ">";

src/atlas4py/_atlas4py.cpp:496

• This class is exported as atlas4py.HybridElements; atlas4py.mesh.HybridElements is not available because no mesh submodule is created.

            oss << "<atlas4py.mesh.HybridElements size=" << he.size() << ">";

src/atlas4py/_atlas4py.cpp:600

• Topology is registered directly on the root module, so atlas4py.mesh.Nodes.Topology is not a valid Python path. Report its actual exported name, atlas4py.Topology.

        return "<atlas4py.mesh.Nodes.Topology>";

• Files reviewed: 2/2 changed files
• Comments generated: 3
• Review effort level: Balanced

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[Copilot]

🟡 Changes recommended

Point representations fail round trips for non-finite coordinates, and the new stream usage lacks its required header.

Once you've addressed the issues Copilot identified, you can request another Copilot review.

Review details

Suppressed comments (2)

Previously missed (1) — in code that hasn't changed since the last review.

src/atlas4py/_atlas4py.cpp:234

• This is not round-trip safe for all accepted double values: Python renders non-finite values as bare inf, -inf, or nan, so evaluating the resulting point representation raises NameError. Format non-finite coordinates as evaluable expressions (for example, float('inf')) and cover them in the round-trip test.

This issue also appears on line 241 of the same file.

src/atlas4py/_atlas4py.cpp:241

• PointXY has the same round-trip failure for accepted non-finite coordinates: nb::str(nb::float_(...)) emits bare inf/nan, which eval cannot resolve. Use an evaluable representation for special floating-point values and add corresponding test cases.

            return "atlas4py.PointXY(x="_s + nb::str( nb::float_( p.x() ) ) + ", y="_s + nb::str( nb::float_( p.y() ) ) + ")"_s;

• Files reviewed: 2/2 changed files
• Comments generated: 1
• Review effort level: Balanced