mock.py

#!/usr/bin/env python3

import argparse
import sys


def digest(infile):
    for line in infile.readlines():
        mock(line)


def mock(line):
    res = ''
    for word in line.split(' '):
        for idx, c in enumerate(word):
            if idx % 2 == 0:
                res += c.lower()
            else:
                res += c.upper()
        if c not in ['\n']:
            res += ' '
    print(res, end='')


if __name__ == '__main__':
    parser = argparse.ArgumentParser(description='Changes case to mock the writer')
    parser.add_argument('text', nargs='?', help='Text to mock')
    parser.add_argument('-i', '--infile', type=argparse.FileType('r'), default=sys.stdin)
    args = parser.parse_args()

    if args.text:
        mock(args.text + '\n')
    else:
        digest(args.infile)