csnake

Csnake is a Python 3 package that helps you generate C code from Python.

Csnake provides you with a consistent and opinionated API that helps you structure your C-generating Python code. It does so by providing classes and functions for generating every C language construct.

Probably the most important feature is the ability to initialize a value to struct and array initializers from Python dicts and lists (actually, Maps and Collections), nested arbitrarily.

Here’s a taste:

from csnake import CodeWriter, Variable, FormattedLiteral
import numpy as np

var = Variable(
    "test",
    primitive="struct whatever",
    value={
        "field1": [{"x": num, "y": 10 - num} for num in range(2)],
        "field2": {"test": range(3), "field": np.arange(6).reshape(2, 3)},
        "field3": FormattedLiteral([30, 31, 32], int_formatter=hex),
        "field4": 8,
    },
)
cw = CodeWriter()
cw.add_variable_initialization(var)
print(cw)

This yields:

struct whatever test = {
    .field1 = {
        {
            .x = 0,
            .y = 10
        },{
            .x = 1,
            .y = 9
        }
    },
    .field2 = {
        .test = {0, 1, 2},
        .field = {
            {0, 1, 2},
            {3, 4, 5}
        }

    },
    .field3 = {0x1e, 0x1f, 0x20},
    .field4 = 8
};

As shown, numpy arrays are supported as values (so are sympy arrays), and values can be formatted by arbitrary functions (here we’re using hex to output ints as hex literals for member field3).

Motivation

Csnake’s varable generation was motivated by a common embedded development task: inputting data into C code.

Csnake should be of help when generating C code for representing data like bitmaps, fonts, statemachines, lookup tables - as arrays and structs. It can also be used for loop unrolling, templating, …

Csnake can be easily incorporated into a build system (Make, CMake, Scons,…), and also goes along great with Jinja2 and Ned Batchelder’s cog.

Documentation

Documentation (Sphinx) can be viewed on GitLab pages for this package.

Examples

Csnake is used on several of my yet-to-be-released open source embedded projects. I’ll be adding those (and other) examples along the way.

Credits

Csnake is a major re-implementation (and improvement) of C-Snake by Oliver (original idea) and Andrej (variable initialization idea and implementation, author of this package).

It’s provided under the MIT license.

Changelog

The changelog can be found within the documentation, here.