pymain 0.2.0

A simplified interface for your main function.

Pymain - Simplified main

Pymain is a decorator and related tools to simplify your main function(s). It is intended to be more simple to use and understand than argparse, while still providing most of the functionality of similar libraries.

Description

The basic idea of pymain is that your main function (though it doesn’t need to be called “main”), and therefore your script or application itself, probably takes parameters and keyword arguments in the form of command line arguments. Since that interface works very similar to calling a python function, pymain translates between those interfaces for you.

Usage

Import and use the @pymain decorator before your main function that has type annotations for the parameters. If you don’t need any short options or aliases, that is all you need to do. Pymain will detect whether the defining module is run as a script (and therefore __name__ == __main__) or if it is being imported. If it is run as a script, then main will be called and given arguments based on sys.argv.

Pymain uses the type annotations to determine what types to expect. For short options or aliases, you can add an @alias decorator after the @pymain decorator describing the alias (either a single alias or a dictionary of multiple)

Examples

optional.py:

from pymain import pymain

@pymain
def main(a: float, b: float, c: str = None):
    print(a / b)
    if c is not None:
        print(c)

Command line:

~ $ python optional.py 4 2
2.0

~ $ python optional.py 9 2 message
4.5
message

keyword.py:

from pymain import pymain

@pymain
def main(first: int, second: int, *, message: str = None):
    print(first + second)
    if message is not None:
        print(message)

Command line:

~ $ python main.py 4 6
10

~ $ python main.py 1 2 --message "Hello, World!"
3
Hello, World!

---

alias.py:

from pymain import pymain, alias

@pymain
@alias({"opt1": "x", "opt2": "y"})
def foo(value: float, *, opt1: float = 1.0, opt2: float = 2.0):
    print(value + opt1)
    print(value - opt2)

Command line:

~ $ python alias.py 2
3.0
0.0

~ $ python alias.py 5 -x 1 -y 1
6.0
4.0

~ $ python alias.py 10 --opt1 5 --opt2 2
15.0
8.0