Fire Comparison

Fire is a CLI parsing library by Google that attempts to generate a CLI from any Python object. To that end, I think Fire definitely achieves it's goal. However, I think Fire has too much magic, and not enough control.

From the Fire documentation:

The types of the arguments are determined by their values, rather than by the function signature where they're used. You can pass any Python literal from the command line: numbers, strings, tuples, lists, dictionaries, (sets are only supported in some versions of Python). You can also nest the collections arbitrarily as long as they only contain literals.

Essentially, Fire ignores type hints and parses CLI parameters as if they were python expressions.

import fire


def hello(name: str = "World"):
    print(f"{name=} {type(name)=}")


if __name__ == "__main__":
    fire.Fire(hello)

$ my-script foo
name='foo' type(name)=<class 'str'>

$ my-script 100
name=100 type(name)=<class 'int'>

$ my-script true
name='true' type(name)=<class 'str'>

$ my-script True
name=True type(name)=<class 'bool'>

The equivalent in Cyclopts:

import cyclopts


app = cyclopts.App()


@app.default
def hello(name: str = "World"):
    print(f"{name=} {type(name)=}")


if __name__ == "__main__":
    app()

$ my-script foo
name='foo' type(name)=<class 'str'>

$ my-script 100
name='100' type(name)=<class 'str'>

$ my-script true
name='true' type(name)=<class 'str'>

$ my-script True
name='True' type(name)=<class 'str'>

Fire is fine for some quick prototyping and has some cool parlour tricks, but is not suitable for a serious CLI. Therefore, I wouldn't say Fire is a direct competitor to Cyclopts.