pymergetic-easybind 0.2.16

Self-registering nanobind helpers (import as pymergetic.easybind)

easybind

Simple self-registering helpers for distributed nanobind bindings.

Install

pip install pymergetic-easybind

import pymergetic.easybind
from pymergetic.easybind import sample  # optional demo module

PyPI project: pymergetic-easybind (install name). Import: pymergetic.easybind.

Version: Set by Git tags at build time (v0.1.0, …) via setuptools-scm; see RELEASING.md. At runtime, pymergetic.easybind._version.__version__ is written when the wheel is built (or use importlib.metadata.version("pymergetic-easybind")).

Local dev / clangd

An editable install configures CMake under ./build/ and generates build/compile_commands.json, which clangd picks up via .clangd — same database as the Python build, no second configure step:

uv pip install -e .    # or: pip install -e .

If you need compile_commands.json without pip, run scripts/clangd-update.sh (plain cmake -S . -B build …).

Python layer

The Python package is implemented as native extensions. It exposes:

• pymergetic.easybind (core helpers and macros)
• pymergetic.easybind.module (module tree API)
• pymergetic.easybind.sample (demo bindings)

Build-time SDK

Installed wheels ship CMake helpers under pymergetic/easybind/cmake/:

• easybind_pip.cmake — easybind_pip_setup() finds Python, nanobind (pip), libeasybind, and include roots for #include <pymergetic/easybind/...>, then pulls in easybind_dependencies.cmake. Helpers: easybind_pip_link_magic_enum(target), easybind_pip_set_rpath_next_to_easybind(target easybind_pkg_dir).
• easybind_dependencies.cmake — pins nanobind, magic_enum, reflect-cpp (same tags as this repo). Use easybind_fetch_third_party_deps() to pull all three, or easybind_fetch_nanobind() / easybind_fetch_magic_enum() / easybind_fetch_reflect_cpp() when you only need a subset (e.g. pip already provides nanobind, so call only easybind_fetch_magic_enum()).

Typical consumer bootstrap:

find_package(Python REQUIRED COMPONENTS Interpreter Development.Module)
execute_process(COMMAND "${Python_EXECUTABLE}" -c
  "import pathlib, pymergetic.easybind; print(pathlib.Path(pymergetic.easybind.__file__).resolve().parent / 'cmake' / 'easybind_pip.cmake')"
  OUTPUT_VARIABLE _eb_pip OUTPUT_STRIP_TRAILING_WHITESPACE COMMAND_ERROR_IS_FATAL ANY)
include("${_eb_pip}")
easybind_pip_setup()
easybind_fetch_magic_enum()   # if you include easybind headers that need magic_enum

When developing inside this repository, easybind_add_extension(...) is defined in the top-level CMakeLists.txt (not shipped in the wheel).

Bumping {distribution}~=… pins (downstream projects)

Use pymergetic.easybind.devtools or the easybind-pin-pyproject CLI to rewrite every compatible-release line {name}~=X.Y.Z in a pyproject.toml for any PyPI distribution name name (not only pymergetic-easybind). Examples:

• cppdantic pinning pymergetic-easybind in several tables.
• A future project pinning cppdantic the same way: pass --distribution cppdantic.

CLI (defaults: distribution=pymergetic-easybind, version = highest v* tag on GitHub — repo URL taken from that distribution’s PyPI metadata; run from the tree that contains pyproject.toml):

easybind-pin-pyproject --dry-run
easybind-pin-pyproject
easybind-pin-pyproject --from-pypi              # PyPI “latest published” instead of GitHub tags
easybind-pin-pyproject --from-github             # same as no flag; optional OWNER/REPO override
easybind-pin-pyproject --from-github ORG/REPO
easybind-pin-pyproject --installed
easybind-pin-pyproject --version 0.2.3
easybind-pin-pyproject --distribution cppdantic
easybind-pin-pyproject --pyproject /path/to/pyproject.toml

Use GITHUB_TOKEN for private GitHub repos or higher API rate limits.

GitHub tags API: responses can be a few seconds behind right after you push a new v* tag. If easybind-pin-pyproject --dry-run still shows the previous release, wait briefly and run again (or pin with --version until the API catches up).

Other devtools CLIs (install pymergetic-easybind first — uv pip install -e . from this repo, or PyPI):

easybind-release-tag --dry-run    # tag message uses [project].name from pyproject.toml
easybind-wait-pypi                # poll PyPI until pins resolve (downstream CI)

Without installing, run the same modules with PYTHONPATH pointing at this repo’s src (e.g. PYTHONPATH=src python -m pymergetic.easybind.devtools.release_tag).

Library:

from pymergetic.easybind.devtools import (
    bump_compatible_pins_in_file,
    fetch_pypi_version,
    github_owner_repo_from_pypi_distribution,
    latest_release_version_from_github,
)

# Match CLI default: latest v* tag on GitHub (same as easybind-pin-pyproject with no version flags)
or_ = github_owner_repo_from_pypi_distribution("pymergetic-easybind")
ver = latest_release_version_from_github(or_)
bump_compatible_pins_in_file("pyproject.toml", "pymergetic-easybind", ver)

# Or: latest published on PyPI (CLI: --from-pypi)
ver = fetch_pypi_version("pymergetic-easybind")
bump_compatible_pins_in_file("pyproject.toml", "pymergetic-easybind", ver)

Shorthands bump_easybind_compatible_pins / bump_easybind_compatible_pins_in_file remain for distribution=\"pymergetic-easybind\" only.

CI (downstream): easybind-wait-pypi wraps wait_pypi_for_compatible_pin in pymergetic.easybind.devtools — poll PyPI until the pinned version exists.

Core idea

• Each namespace/module defines a ModuleNode and a bind callback.
• The module entry point calls apply_init to run the callback and recurse.
• Submodules are created on demand and registered in sys.modules.
• Shared-object modules are marked so recursion stops at their boundary.
• A minimal sample module lives at pymergetic.easybind.sample.

Developer note: layout rules

• __init__.cpp marks the Python boundary (NB_MODULE) for a package/module.
• node.cpp/.hpp is the pure C++ module-tree core.
• ns_module.hpp defines the EASYBIND_NS_MODULE* macros.
• Directory layout mirrors namespaces and Python modules.

Smallest possible example

1) Define a C++ type (normal code)

#pragma once

#include <string>

struct PeerInfo {
    std::string peer_id;
    int transport = 0;
};

2) Bind it in a separate file (module node)

#include <pymergetic/easybind/bind.hpp>

struct PeerInfo;  // forward declare or include the header

EASYBIND_NS_MODULE(my_pkg, m, false, {
    nanobind::class_<PeerInfo>(m, "PeerInfo")
        .def(nanobind::init<>())
        .def_rw("peer_id", &PeerInfo::peer_id)
        .def_rw("transport", &PeerInfo::transport);
});

3) Module entry point (shared-object boundary)

Use this only for the package that has its own .so and NB_MODULE entry point. Do not pair it with EASYBIND_NS_MODULE for the same my_pkg name. If you need to add bindings from another file, use EASYBIND_NS_MODULE_EXTEND to extend the same module node instead.

#include <pymergetic/easybind/bind.hpp>

EASYBIND_NS_MODULE_SHARED_OBJECT(my_pkg, my_pkg, m, true, {
    m.doc() = "my_pkg module";
});

4) Extend from another file

#include <pymergetic/easybind/bind.hpp>

EASYBIND_NS_MODULE_EXTEND(my_pkg, m, {
    m.def("ping", [] { return "pong"; });
});