just-makeit 0.1.1

Scaffold and build Python C extensions with CMake and just-buildit.

Python C extensions the easy way.

just-makeit new scaffolds a complete, working C99 extension project in one command: core C library, thin Python binding, CMake build system, and full test coverage — no boilerplate to write.

---

Installation

pip install just-makeit

---

Quickstart

just-makeit new my_project --component engine --state gain:double:1.0
cd my_project && make && make test

What you get:

my_project/
├── native/
│   ├── inc/
│   │   ├── clib_common.h           # common C99 types
│   │   ├── pyex_common.h           # Python extension includes
│   │   └── engine/
│   │       └── engine_core.h       # component API
│   ├── src/
│   │   └── engine/
│   │       ├── CMakeLists.txt
│   │       ├── engine_core.c       # core logic — your algorithm goes here
│   │       └── engine_ext.c        # thin Python binding
│   └── tests/
│       └── test_engine_core.c      # CTest
├── src/my_project/
│   ├── __init__.py
│   ├── engine.pyi                  # type stub
│   └── tests/
│       └── test_engine.py          # pytest / unittest
├── CMakeLists.txt
├── Makefile
├── pyproject.toml
└── just-makeit.toml

---

Commands

Command	Description
just-makeit new <project> [--component name] [--state ...]	Create a new project (optionally with a first component)
just-makeit init <component> [--state ...]	Add a component to an existing project
just-makeit add --state name:type[:default] [...]	Add state variables to a component
just-makeit config [key value]	Show or edit project configuration
just-makeit build [dir]	Configure + build C, then package a wheel
just-makeit test	Build and run CTest + pytest
just-makeit dry-run	Preview what would be compiled

State types: double, float, int. Default value is 0 for each type if omitted. Both reset and the Python __init__ use the declared default — Engine() with no args is valid.

---

C conventions

Generated code follows a consistent lifecycle pattern:

// Constructor — parameters match your --state declarations
engine_state_t *engine_create(double gain);

// Destructor
void engine_destroy(engine_state_t *state);

// Reset — restores every variable to its declared default
void engine_reset(engine_state_t *state);

// Single sample (inlined, pass-through stub — implement your algorithm here)
static inline float complex
engine_step(const engine_state_t *state, float complex x);

// Block processor
void engine_steps(
    engine_state_t *state,
    const float complex *input,
    float complex       *output,
    size_t               n);

// Getter / setter for each --state variable
double engine_get_gain(const engine_state_t *state);
void   engine_set_gain(engine_state_t *state, double gain);

---

Python API

from my_project import Engine
import numpy as np

obj = Engine(gain=1.0)   # explicit
obj = Engine()           # uses declared defaults

# single sample
y: complex = obj.step(1.0 + 0.5j)

# block processing
x = np.ones(1024, dtype=np.complex64)
y = obj.steps(x)   # returns complex64 ndarray

# getters / setters
obj.get_gain()
obj.set_gain(2.0)

# reset restores declared defaults
obj.reset()

# context manager
with Engine() as e:
    y = e.steps(x)

---

Multiple state variables

just-makeit new my_project \
    --component engine \
    --state center_freq:double:1000.0 \
    --state bandwidth:double:200.0 \
    --state order:int:4

Each --state name:type:default becomes a struct field, a constructor parameter (optional in Python, required in C), getter/setter pair, and reset target — in both C and Python.

---

Integrations

• CMake — Python3_add_library with WITH_SOABI; .so lands in src/ for zero-install dev workflow
• GNU Make — convenience wrapper with build, test, and just-build targets
• NumPy buffer protocol — steps() accepts and returns complex64 ndarrays
• pytest — tests generated covering create, step, steps, getters/setters, reset, context manager, and destroy
• CTest — C-level test for the core lifecycle
• just-buildit — PEP 517 backend; pip install . and pip install -e . work out of the box

---

Packaging

The generated project uses just-buildit as its PEP 517 build backend.

# Build and install
pip install .

# Development install (no rebuild needed after editing Python files)
pip install -e .

# Build a wheel manually
just-makeit build

---

Examples

See examples/gain/ for a complete generated project.

---

Requirements

• Python 3.11+
• CMake ≥ 3.16
• A C99 compiler (GCC, Clang, MSVC/MinGW)
• NumPy (runtime, for generated projects)