[UmutAlisoglu]

The containment docstrings say that self contains the given pointer, but the implementation checks whether the argument's parts are a prefix of self. For example, child.contains(parent) and parent in child return true.

Clarify this direction in the API docs and tutorial, with executable examples for both directions, equal/root pointers and whole-part matching (/foo/b is not a prefix of /foo/bar). Runtime behavior is unchanged.

Validation on Windows / Python 3.14.7: all 74 tests pass, including the new doctests; Flake8 passes; the Sphinx HTML build passes with warnings treated as errors.

AI-assisted with OpenAI Codex, including editing and verification.

[Copilot]

🟢 Approval recommended

The documentation and examples accurately describe the unchanged implementation, with no unresolved issues.

No open issues 🎉

What changed in this PR

This PR clarifies the direction of JSON Pointer containment checks without changing runtime behavior.

Changes:

• Corrects API docstrings to explain that the argument’s parts must be a prefix of the receiver’s parts.
• Adds doctests covering direction, equality, root pointers, and whole-part matching.
• Adds tutorial guidance showing the equivalent parent in child expression.

File	Description
jsonpointer.py	Clarifies containment docstrings and adds executable examples.
doc/​tutorial.rst	Explains pointer-prefix checks and membership direction.

_{Review effort: Balanced}

[coveralls]

coverage: 97.714%. remained the same — UmutAlisoglu:codex/document-pointer-prefix-direction into stefankoegl:master

[stefankoegl]

Thanks!