Modular•15mo ago

cmd args parse

I want to use the argparse package in Python, but it's painful to write a mojo code like

from python import (Python, PythonObject)

fn main():
    try:
        let ap = Python.import_module("argparse")
        let parser = ap.ArgumentParser()
        parser.add_argument(...) # this line is painful since key args are not supported yet
        ...
    except e:
        print(e.value)

from python import (Python, PythonObject)

fn main():
    try:
        let ap = Python.import_module("argparse")
        let parser = ap.ArgumentParser()
        parser.add_argument(...) # this line is painful since key args are not supported yet
        ...
    except e:
        print(e.value)

thus I think it will be more reasonable to implement a simple argparse in mojo.... The question is that is there any existing codes? or would Modular offer official module in the future?

9 Replies

rd4com•15mo ago

yes there are thoses features and if you want, you can pass -D key=value to mojo https://docs.modular.com/mojo/stdlib/os/env.html https://docs.modular.com/mojo/stdlib/sys/arg.html https://docs.modular.com/mojo/stdlib/sys/param_env.html

Modular Docs - env

Module

Modular Docs - arg

Module

Modular Docs - param_env

Module

ziyu4huang•15mo ago

I will do whole things in Python to handle args in python only. Simply. in main.mojo fn main(): let args_dict = Python.import_module("my_app").parse() ... do things in mojo. in my_pp.py: def parse(): parser = argparse.ArgumentParser(): parser.add_argument(...) # do the easy things in Python. Really, there is no benefit to write simple glue code in Mojo. It wil be painful and useless .

rd4com•15mo ago

yes, good use!

Jack Clayton•15mo ago

Mojo has this: https://docs.modular.com/mojo/stdlib/sys/arg.html Keyword arguments are being worked on currently

bhavnicksm•15mo ago

Hey @Jack Clayton, could you give an example on how to use this function argv? Mojo is throwing a errors when I am trying it in a pythonic fashion

Jack Clayton•15mo ago

Hi @bhavnicksm sure:

from sys import argv

fn main():
    print(argv()[1])

from sys import argv

fn main():
    print(argv()[1])

Then you can pass in the argument:

mojo run argvtest.mojo arg1

mojo run argvtest.mojo arg1

But it does result in a crash if you don't pass in the arg, I've raised an issue here for that: https://github.com/modularml/mojo/issues/827

bhavnicksm•15mo ago

Thanks @Jack Clayton!

arboverda•10mo ago

would have to check length of argv() before accessing argv()[1], right? I mean, to avoid the crash, you've mentioned actually - now it no longer crashes but prints "(null)"

Jack Clayton•10mo ago

Yeah should do that

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cmd args parse