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filter_module example

A two-type filter library where Fir (FIR filter) and Biquad (biquad IIR) share a single Python extension module — one .so, one subpackage import.

Source: examples/filter_module/

What it demonstrates

Feature Where
just-makeit module Step 2 — scaffold an empty module slot
just-makeit object Step 3 — add Fir and Biquad to the module
Module regeneration Each object call fully rewrites filter_ext.c, CMakeLists, and __init__.py
Single-import subpackage from my_filters.filter import Fir, Biquad
CHECK macro C tests Both objects get failure-counting C tests (no silent assert)
-lm on test/bench Auto-linked; math functions work without manual CMake edits

Key workflow

just-makeit new my_filters
cd my_filters

just-makeit module filter

just-makeit object fir    --module filter --state "coeffs:float[16]" --state "delay:float _Complex[16]" --state "gain:float:1.0"
just-makeit object biquad --module filter --state "b0:float:1.0f" --state "b1:float:0.0f" --state "b2:float:0.0f" \
                                          --state "a1:float:0.0f" --state "a2:float:0.0f" \
                                          --state "w1:float:0.0f" --state "w2:float:0.0f"

After these three commands:

native/src/
  fir/
    fir_core.h / fir_core.c          ← C library (OBJECT lib, no .so)
    CMakeLists.txt                    ← OBJECT + test + bench targets
  biquad/
    biquad_core.h / biquad_core.c
    CMakeLists.txt
  filter/
    filter_ext.c                      ← FirObject + BiquadObject + PyInit_filter
    CMakeLists.txt                    ← links fir_core + biquad_core → filter.so

src/my_filters/
  filter/
    __init__.py                       ← from .filter import Fir, Biquad
    filter.cpython-*.so               ← built here by CMake

Adding a third type later is one command:

just-makeit object iir --module filter --state "sos:float[20]" --state "zi:float[10]"

filter_ext.c, CMakeLists.txt, and __init__.py are regenerated from scratch. Fir and Biquad are untouched.

See also