Question

maybe the title is not very clear, let me elaborate.

I have a python script that open a ppm file , apply a chosen filter(rotations…) and create a new picture. until here everything work fine.

but I want to do the same thing through a linux console like:

ppmfilter.py ROTD /path/imageIn.ppm /path/imageOut.ppm

here ROTD is the name of the function that apply a rotation.

I don’t know how to do this, I’m looking for a library that’ll allow me to do this.

looking forward for your help.

P.S.: I’m using python 2.7

Answer 1

There is a relatively easy way:

You can determine the global names (functions, variables, etc.) with the use of ‘globals()’. This gives you a dictionary of all global symbols. You’ll just need to check the type (with type() and the module types) and if it’s a function, you can call it with sys.argv:

import types
import sys

def ROTD(infile, outfile):
    # do something

if __name__ == '__main__':
    symbol = globals().get(sys.argv[1])
    if hasattr(symbol, '__call__'):
        symbol(*sys.argv[2:])

This will pass the program argument (excluding the filename and the command name) to the function.

EDIT: Please, don’t forget the error handling. I omited it for reasons of clarity.