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Is Rustpython Capi Expansion free to use?

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tomevault-io (@tomevault-io) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Rustpython Capi Expansion by tomevault-io

Name: Rustpython Capi Expansion
Author: tomevault-io

Rustpython Capi Expansion

Implement missing RustPython C-API functions in crates/capi using the pyo3-ffi header split mapping (`pyo3-ffi/src/*.rs`, mirroring CPython C API headers). Use this whenever the user asks to add or port C-API functions (for example from setobject.h, dictobject.h, unicodeobject.h) or add capi tests. Use when this capability is needed.

tomevault-io Updated Sep 17, 2026

File contents

RustPython C-API Expansion

Use this workflow for adding missing C-API functions to RustPython.

Source of truth for target files

Use this mapping source: pyo3-ffi/src/*.rs, which mirrors the CPython header split used by the C API.
Map requested header APIs to crates/capi/src/<header_basename>.rs using that split. Examples:
- setobject.h -> crates/capi/src/setobject.rs
- dictobject.h -> crates/capi/src/dictobject.rs
- unicodeobject.h -> crates/capi/src/unicodeobject.rs
Do not invent alternate target modules when the header split implies a direct target.
If the target file is not present yet, create it and wire it in crates/capi/src/lib.rs.

Implementation workflow

Identify requested missing APIs from the user request and their originating C API header.
Open nearby capi modules in crates/capi/src/ and follow existing style and patterns.
Implement only the requested functions in the mapped target file.
Keep behavior aligned with CPython C-API contracts.
Prefer using existing rustpython-vm functionality as much as possible instead of re-implementing behavior in capi.
If a needed rustpython-vm helper exists but is private, make it public with a minimal, focused visibility change.
Prefer direct contract assumptions over defensive null checks unless required by the established local style.
Add basic tests only; do not overfit with very specific edge-case clutter.
In tests, use pyo3 only as a safe wrapper over the API. Avoid raw pointer-heavy direct FFI-style tests.
Run tests from crates/capi.

Testing rules

Run test commands with working directory set to crates/capi.
Prefer targeted tests first (module/function filter), then broader capi tests if needed.
Keep test names concise (no required test_ prefix).

Style rules

Follow existing RustPython capi coding style in neighboring files.
Reuse rustpython-vm methods and types first; avoid duplicating VM logic in capi wrappers.
When exposing previously private VM helpers, keep the API surface minimal and avoid unrelated refactors.
Only expose and implement ABI-stable C-API surface needed for abi3 / abi3t.
Add comments only when they explain non-obvious behavior.
Keep edits minimal and focused on requested API expansion.

Completion checklist

All requested functions implemented in mapped target file.
New module exported in crates/capi/src/lib.rs when applicable.
Basic safe-wrapper pyo3 tests added/updated.
Tests executed from crates/capi and passing for changed area.
Final response includes changed file paths and test command summary.

Example prompts this skill should handle

"Implement these missing functions from dictobject.h."
"Add setobject.h C-API functions in RustPython and include basic tests."
"Port the listed unicodeobject.h APIs in capi, follow existing style, and run tests from crates/capi."

Source: RustPython/RustPython — distributed by TomeVault.

---name: rustpython-capi-expansiondescription: Implement missing RustPython C-API functions in crates/capi using the pyo3-ffi header split mapping (`pyo3-ffi/src/*.rs`, mirroring CPython C API headers). Use this whenever the user asks to add or port C-API functions (for example from setobject.h, dictobject.h, unicodeobject.h) or add capi tests. Use when this capability is needed.---# RustPython C-API ExpansionUse this workflow for adding missing C-API functions to RustPython.## Source of truth for target files- Use this mapping source: `pyo3-ffi/src/*.rs`, which mirrors the CPython header split used by the C API.- Map requested header APIs to `crates/capi/src/<header_basename>.rs` using that split. Examples: - `setobject.h` -> `crates/capi/src/setobject.rs` - `dictobject.h` -> `crates/capi/src/dictobject.rs` - `unicodeobject.h` -> `crates/capi/src/unicodeobject.rs`- Do not invent alternate target modules when the header split implies a direct target.- If the target file is not present yet, create it and wire it in `crates/capi/src/lib.rs`.## Implementation workflow1. Identify requested missing APIs from the user request and their originating C API header.2. Open nearby capi modules in `crates/capi/src/` and follow existing style and patterns.3. Implement only the requested functions in the mapped target file.4. Keep behavior aligned with CPython C-API contracts.5. Prefer using existing `rustpython-vm` functionality as much as possible instead of re-implementing behavior in capi.6. If a needed `rustpython-vm` helper exists but is private, make it public with a minimal, focused visibility change.7. Prefer direct contract assumptions over defensive null checks unless required by the established local style.8. Add basic tests only; do not overfit with very specific edge-case clutter.9. In tests, use `pyo3` only as a safe wrapper over the API. Avoid raw pointer-heavy direct FFI-style tests.10. Run tests from `crates/capi`.## Testing rules- Run test commands with working directory set to `crates/capi`.- Prefer targeted tests first (module/function filter), then broader capi tests if needed.- Keep test names concise (no required `test_` prefix).## Style rules- Follow existing RustPython capi coding style in neighboring files.- Reuse `rustpython-vm` methods and types first; avoid duplicating VM logic in capi wrappers.- When exposing previously private VM helpers, keep the API surface minimal and avoid unrelated refactors.- Only expose and implement ABI-stable C-API surface needed for `abi3` / `abi3t`.- Add comments only when they explain non-obvious behavior.- Keep edits minimal and focused on requested API expansion.## Completion checklist- [ ] All requested functions implemented in mapped target file.- [ ] New module exported in `crates/capi/src/lib.rs` when applicable.- [ ] Basic safe-wrapper `pyo3` tests added/updated.- [ ] Tests executed from `crates/capi` and passing for changed area.- [ ] Final response includes changed file paths and test command summary.## Example prompts this skill should handle- "Implement these missing functions from `dictobject.h`."- "Add `setobject.h` C-API functions in RustPython and include basic tests."- "Port the listed `unicodeobject.h` APIs in capi, follow existing style, and run tests from `crates/capi`."---> Source: [RustPython/RustPython](https://github.com/RustPython/RustPython) — distributed by [TomeVault](https://tomevault.io).

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