arglite

A lightweight, explicit argument parsing library for Python programs.

I made this for a teaching machine project I'm working on (I needed a custom argument parser for reasons), and I'm always too impatient to use argparse.

Quick start

import arglite

arglite.parser.require("name", type=str)
arglite.parser.optional("count", default=1, type=int)
arglite.parser.flag("verbose")

def main():
    print(arglite.parser.name)
    print(arglite.parser.count)
    print(arglite.parser.verbose)

if __name__ == "__main__":
    main()

python main.py --name Yo --count 5 --verbose

YAML configuration

You can also declare flags in a .arglite.yaml file in the working directory. arglite loads it automatically, or you can point to a different file with parser.load().

flags:
  name:
    help: "The user name"
    type: str
    required: true

  count:
    help: "Number of items"
    type: int
    default: 1

  verbose:
    help: "Enable verbose output"
    action: store_true

import arglite

print(arglite.parser.name)
print(arglite.parser.count)
print(arglite.parser.verbose)

Python declarations override YAML for runtime behavior (type, required, default, action), while YAML metadata like help and choices is merged in.

Documentation

Full documentation is available at arglite.readthedocs.io.

Installation

pip install arglite

Notes

• Flags are case-sensitive.
• Both -f / --flag and --flag=value / -f=value syntaxes are supported.
• Values containing spaces work when passed via the shell's normal quoting rules.
• Empty string values (--name "") are preserved.
• ast.literal_eval is used for type inference when no explicit type is given.