Python bindings for dos-like

python-dos-like is a set of Python bindings for the dos-like programming library by Mattias Gustavsson.

Documentation: https://python-dos-like.readthedocs.io/en/latest/

Source Code: https://github.com/cknave/python-dos-like

Usage

pip install python-dos-like

python-dos-like can be used in the same way as dos-like by calling dos_like.start on your main function:

from random import randrange

import dos_like
from dos_like.dos import *


def main():
    setvideomode(videomode_320x200)

    while not shuttingdown():
        waitvbl()
        for _ in range(50):
            setcolor(randrange(256))
            line(randrange(320), randrange(200), randrange(320), randrange(200))
            setcolor(randrange(256))
            fillcircle(randrange(320), randrange(200), randrange(30))
            setcolor(randrange(256))
            circle(randrange(320), randrange(200), randrange(30))

dos_like.start(main)

You can also use python-dos-like in the Python REPL by calling dos_like.run_in_background:

>>> import dos_like
>>> from dos_like.dos import *
>>> dos_like.run_in_background(['-w'])
>>> cputs('hello world!')

Note

Why the ['-w']? This passes the -w flag through to dos-like, which tells it to run in windowed mode. Without it, dos-like starts in full screen and you have to press F11 to enter windowed mode.

Building

Building python-dos-like requires C development tools to be installed.

On Linux and macOS, the SDL2 and GLEW libraries are required.

If building from a git repository, you must update submodules to get the dos-like source.

git submodule update --init --recursive

$ python -mvenv .venv
$ . .venv/bin/activate
(.venv) $ pip install -e '.[dev]'
(.venv) $ coverage run -m unittest && coverage report

Several environment variables may be set to control compile-time options:

Environment variable	Default	Description
`ALWAYS_UPDATE`	1	Update the screen in the background. Set this to `0` to restore dos-like's default behavior of pausing updates when the window loses focus.
`CFLAGS`		Extra compiler flags. Of note, `-DNULL_PLATFORM` is useful to build a library for headless build servers.

Limitations

Memory management

Memory allocated by dos-like will be freed when its corresponding bython buffer object is garbage collected. The current draw target and music will be retained even if no other python code has a reference, but any playing sounds will not be. Deleting or releasing the last reference to a playing sound may cause issues.

Platforms

This library has been tested on Linux, Windows, and macOS.

macOS does not support GUI operations in a background thread, so it cannot be used from the Python REPL by calling run_in_background().

python-dos-like can be compiled as a WebAssembly Pyodide module, but will fail to import due to a missing symbol from WAjic. Even if this symbol (J, an object containing JS functions to be called from C) is added to the imports when loaded by Pyodide, it does not appear to be compatible.

It is not clear to me what the best way forward is for WebAssembly support: getting a Pyodide module to import WAjic functions, building a Pyodide module in WAjic, or removing Pyodide or WAjic from the project entirely.