linechecker

#!/usr/bin/env python3

import argparse
import sys

"""
Check a plaintext document for lines containing uneven numbers of search characters.
Useful for finding lines in a LaTeX document with extra $, { etc. inserted, when
the compiler output isn't being useful
"""

seach_pairs = [('{', '}'), ('"', ''), 
               ('$', ''), ('(', ')')]
# TODO add some method for adding / removing more seach pairs

if __name__ == "__main__":
    # parse arguments
    parser = argparse.ArgumentParser(description="Find lines of the input document containing uneven pairs of seach characters.")
    parser.add_argument("-i", "--infile", type=str, default=None,
            help="Input file to seach, default stdin")
    args = parser.parse_args()

    with (open(args.infile, 'r') if args.infile else sys.stdin) as infile:
        for line_num, line in enumerate(infile):
            for incrementer,decrementer in seach_pairs:
                if decrementer == '':
                    count = line.count(incrementer) % 2
                else:
                    count = line.count(incrementer) - line.count(decrementer)
                if count is not 0:
                    outstring = "Line {0}: {1} {2} unmatched (diff {3})\n{4}"
                    print(outstring.format(line_num+1, incrementer, decrementer, 
                        count, line))