pyturbo-v3 3.0.6

PyTurbo V3

Python 3.10 to C99 transpiler with CPython API and DCE.

Optimization method: all you can make to C99; the rest through CPython API.

Author: Suleiman License: Apache 2.0 Copyright 2026 Suleiman

QUICK START

pyturbo transpile hello.py -o hello.c -v

Output:

hello.c              C99 + inline CPython declarations (~5 KB)
hello.h              function prototypes
hello.manifest.json  full analysis report

Compile with any C compiler:

gcc -std=c99 hello.c -lpython3.11 -o hello
./hello

Or MinGW, clang, tcc, MSVC. Any of them works.

PLATFORM SUPPORT

Windows 10 / 11 (64-bit)    full support, recommended
Linux / macOS / Android     .c output only (no --min-dll)

PyTurbo V3 is designed and tested for Windows first. The transpiler itself (analyzer, type inference, codegen, DCE) is platform-independent and produces standard C99. The --min-dll feature (isolated pythonXY.dll + UPX) is Windows-only, because it relies on the PE format and Windows DLL loading rules.

On Linux / macOS / Android: - .c and .h output works - --min-dll is a no-op with a warning - link against system libpythonXY.so - example: gcc -shared -fPIC hello.c -lpython3.11 -o hello.so

To enable transpilation on non-Windows platforms, remove or relax the platform guard in pyturbo.py:

# was:
if sys.platform != "win32":
    _fail_os()

# now:
if sys.platform != "win32":
    import warnings
    warnings.warn(
        "PyTurbo: --min-dll is Windows-only; .c output works everywhere"
    )

This is the only change required for .c output on Linux/macOS/Android.

FEATURES

C99 where possible:

numbers                                -> double
arithmetic                             -> native + - * /
for i in range(n)                      -> for (double i = 0; i < n; i += 1)
+=, -=, *=, ...                        -> native
print(x, y)                            -> printf("%g %g\n", x, y)
numeric function parameters            -> unboxed to double
numeric return values                  -> boxed via PyFloat_FromDouble

CPython API fallback:

strings, lists, tuples, dicts
imports, module calls
classes (via type())
exceptions
lambdas

DCE for Python.h:

reads Python.h from the system
extracts only the used prototypes (~15 of ~1800)
inlines them into the .c file
no #include <Python.h>
no -I flag needed
portable .c

DLL isolation on Windows with --min-dll:

detects the running Python version (310, 311, 312, 313, ...)
finds pythonXY.dll
produces an isolated copy next to the .c file
no Visual Studio required
uses a pure-Python PE parser

Then:

cd pyturbo_dist
gcc hello.c -L. -lpython311 -o hello.exe

Or with MSVC, clang, tcc. Any of them.

COMMANDS

pyturbo transpile <file.py> [-o out.c] [-v] [--min-dll] [--as-extension]
pyturbo analyze   <file.py>
pyturbo infer     <file.py>
pyturbo tokens    <file.py>
pyturbo version
pyturbo help

EXAMPLE

import math

def sum_squares(n):
    total = 0
    for i in range(n):
        total += i * i
    return total

def main():
    r = sum_squares(100)
    print("Result:", r)
    print("Sqrt:", math.sqrt(r))

main()

Generated C (excerpt):

PyObject* py_user_sum_squares(PyObject* py_n) {
    double py_n_v = PyFloat_AsDouble(py_n);
    double py_total = (double)((0L));
    for (double py_i = (double)((0));
         py_i < (double)(py_n_v);
         py_i += (double)((1))) {
        py_total += py_i * py_i;
    }
    return PyFloat_FromDouble(py_total);
}

PyObject* py_user_main(void) {
    PyObject* py_r = py_user_sum_squares(PyLong_FromLong(100L));
    double py_r_v = PyFloat_AsDouble(py_r);
    printf("Result: %g\n", py_r_v);

    PyObject* _m = PyImport_ImportModule("math");
    PyObject* _f = PyObject_GetAttrString(_m, "sqrt");
    PyObject* _t = PyObject_Vectorcall(_f, &py_r, 1, NULL);
    double _t_v = PyFloat_AsDouble(_t);
    printf("Sqrt: %g\n", _t_v);

    Py_INCREF(Py_None);
    return Py_None;
}

C EXTENSIONS

PyTurbo output is already a valid C extension. It only lacks the module boilerplate. You can add it manually, or (once --as-extension is implemented) let PyTurbo emit it.

Manual boilerplate (~20 lines):

static PyMethodDef module_methods[] = {
    {"sum_squares", py_user_sum_squares, METH_O, NULL},
    {"main",        py_user_main,        METH_NOARGS, NULL},
    {NULL, NULL, 0, NULL}
};

static struct PyModuleDef module_def = {
    PyModuleDef_HEAD_INIT,
    "hello",
    NULL,
    -1,
    module_methods
};

PyMODINIT_FUNC PyInit_hello(void) {
    return PyModule_Create(&module_def);
}

Build as an extension:

gcc -shared -fPIC hello.c -lpython3.11 -o hello.so
# or on Windows:
gcc -shared hello.c -L. -lpython311 -o hello.pyd

Import:

python -c "import hello; hello.sum_squares(100)"

What this gives you:

.c size        ~5 KB        (Cython: ~500 KB)
.so size       ~50 KB       (Cython: ~1 MB)
dependencies   0            (Cython: 3)
Python.h       not needed   (Cython: #include <Python.h>)
-I flag        not needed   (Cython: needed)
build time     seconds      (Cython: minutes)
input          .py          (Cython: .pyx)

Limitations compared to Cython:

NumPy          not supported
C++            not supported
cdef class     not supported (classes are built at runtime)
attribute specialization   not supported
object-heavy speed          ~1x (Cython: 2-10x)
ecosystem      none         (Cython: 18 years)

So: PyTurbo is a lightweight alternative to Cython for small, numeric, pure-Python extensions - not a general replacement.

SPEED

Realistic speedup range over CPython: 6x to 50x.

50x     upper bound: fully numeric hot path
6x      lower bound: mixed numeric + object code
~1x     object-heavy code (same as CPython)
<1x     worst case: print(object) in loop, m.f(x) in loop

The 50x figure applies only to numeric code that fully passes try_pure_c99. On object-heavy code PyTurbo emits generic CPython API calls and may be slower than CPython due to repeated ImportModule / GetAttrString.

This is not a bug; it is the boundary of the model: "all you can to C99, the rest through CPython API".

SIZE COMPARISON

feature                PyTurbo V3   Cython       Nuitka
---------------------  -----------  -----------  -----------
input                  .py          .pyx         .py
annotations            not needed   needed       not needed
output                 .c           .c           .c / .exe
.c size                ~5 KB        ~500 KB      ~1 MB
binary                 ~50 KB       ~1 MB        ~5 MB
dependencies           0 (CPython)  3            5
Python.h               inlined      #include     #include
DLL DCE (Windows)      copy + UPX   no           no
works on Android       .c only      no           no
speed (numeric)        ~50x         ~50x         ~1.3x
speed (objects)        ~1x          2-10x        1.3x

PYTURBO VS CYTHON

Cython requires .pyx syntax with cdef, cpdef. PyTurbo accepts pure Python and infers types automatically.

Cython: full plate armor: .pyx, cdef, cpdef broadsword: #include <Python.h> (~1800 prototypes) castle: ~3 MB package, 150,000 lines 500 contributors 18 years old

PyTurbo: t-shirt: pure .py scalpel: inline Python.h (~15 prototypes) laptop: 34 KB, ~3200 lines 1 author brand new

Both produce fast C. Both are peers in the same category. Different eras, different styles.

Where PyTurbo wins:

input is pure .py (no .pyx)
.c is ~100x smaller
no #include <Python.h>
no -I flag
0 dependencies
build time: seconds
Windows distribution with isolated UPX-compressed DLL
.c output works on Linux / macOS / Android

Where Cython wins:

NumPy integration
C++ integration
cdef class (real C types)
attribute / method specialization
object-heavy speed (2-10x)
production ecosystem (18 years, 500 contributors)

PYTURBO VS NUITKA

Nuitka compiles for packaging (.exe). PyTurbo focuses on generating minimal C with DCE.

Nuitka pulls in the full Python runtime. PyTurbo removes unused declarations and inlines only the needed ~15 prototypes directly into the .c file.

DCE

Cython and Nuitka both require #include <Python.h> and pull in all ~1800 prototypes.

PyTurbo removes unused declarations and inlines only the needed ~15 prototypes directly into the .c file.

On Windows with --min-dll, PyTurbo also isolates pythonXY.dll next to the .c file, so the .exe loads our copy first (Windows side-by-side rule).

No Visual Studio required. Uses a pure-Python PE parser.

Note: the PE parser (pe_parser.py) is Windows-only by design. It reads PE files, not ELF. It is not needed for .c output; it is only used by --min-dll.

WHY PYTURBO

Not a new category. A minimal implementation in an existing category.

Category: Python-to-C transpilers. Peers: Cython, Nuitka.

PyTurbo is the best when you want:

pure Python input, no annotations
tiny .c (5 KB)
no -I flag
no #include <Python.h>
0 dependencies
small C extensions (~50 KB .so)
minimal Windows distribution (isolated DLL + UPX)
.c output on Linux / macOS / Android
fast build cycle (seconds)

Cython is the best when you want:

numpy integration
C++ integration
maximum speed with annotations
cdef class
production ecosystem

Nuitka is the best when you want:

.exe packaging
full Python compatibility
no annotations needed

HONEST LIMITATIONS

Windows is the primary platform.
    --min-dll, pe_parser.py, dll_decreaser.py, embed.py
    are Windows-only. The transpiler core is portable,
    but pyturbo.py currently blocks non-Windows at startup.
    Remove the platform guard to enable .c output elsewhere.

No NumPy.
    PyTurbo does not understand ndarray, memoryview, or
    buffer protocols. numpy calls go through CPython API.

No C++.
    PyTurbo emits C99 only.

Classes are dynamic.
    class Foo: is built at runtime via PyType_Type.
    It is not a real C type.

Object-heavy code is not faster.
    print(obj), m.f(x), obj.attr in loops may be slower
    than CPython due to repeated ImportModule / GetAttrString.

Half of Python syntax is not implemented.
    Missing: with, try, raise, lambda, yield, await,
    decorators, f-strings, match. These are not C99
    limitations - they are unimplemented in codegen.py.

DCE reads Python.h from the system.
    It is needed at transpile time, not at compile time.
    Without it, PyTurbo falls back to a hardcoded set
    of ~80 prototypes.

--as-extension is not implemented yet.
    Output is a standalone .exe (with main()).
    To build a C extension, add the module boilerplate
    manually (see C EXTENSIONS section).

LICENSE

Apache License 2.0. See LICENSE.txt.