Purge Comments from LaTeX

purge-tex-comments.py

#! /usr/bin/env python3

import sys
import re

with open(sys.argv[1], "rt") as infile:
    tex = infile.read()

tex, _ = re.subn("%.*\n", "", tex)
tex, _ = re.subn(r"\\begin\{comment\}.*\\end\{comment\}", "", tex, flags=re.DOTALL)

def remove_macro_with_argument(macro, s):

    i = 0
    while True:
        start = s.find(macro, i)
        if start == -1:
            break

        i = start + len(macro)

        if s[i] == "#":
            # That's the definition, keep going.
            continue

        assert s[i] == "{"
        level = 1
        i += 1

        while i < len(s):
            c = s[i]
            i += 1

            if c == "{":
                level += 1
            elif c == "}":
                level -= 1
                if level == 0:
                    break

        s = s[:start] + s[i:]
        i = start

    return s

tex = remove_macro_with_argument(r"\iftechreport", tex)

print(tex)