c++ template error message decoder and colorizer

templatedecode.py

#!/usr/bin/env python3

"""
C++ template error message decoder and colorizer.

Copyright (C) 2017 Jonas Jelten <jj@stusta.net>

Licensed under GNU GPLv3 or later.
"""

import argparse
import sys


def main():
    """
    Decode and colorize template error messages.
    It can surely be improved, but it was written while in rage.
    """

    cmd = argparse.ArgumentParser()
    cmd.add_argument("-c", "--no-color", action="store_true",
                     help="don't colorize output")

    args = cmd.parse_args()

    print("pls giev template data on stdin...")

    data = []
    while True:
        read = sys.stdin.buffer.read()
        if not read:
            break

        data.append(read)

    indent_per_level = 4
    indent = 0
    in_quotes = False
    opentags = 0

    current_line = bytearray()
    output = []

    for group in data:
        for char in group:
            if char == ord("\n"):
                continue

            elif char == ord(","):
                # newline after ,
                current_line.append(char)
                output.append((indent, current_line))
                current_line = bytearray()

            elif char == ord("'"):
                # newline after ' if in quotes
                if in_quotes:
                    output.append((indent, current_line))
                    current_line = bytearray()
                    current_line.append(char)
                    in_quotes = False

                else:
                    current_line.append(char)
                    output.append((indent, current_line))
                    current_line = bytearray()
                    in_quotes = True


            elif char == ord("<"):
                # newline after < then indent
                current_line.append(char)
                output.append((indent, current_line))
                current_line = bytearray()
                indent += indent_per_level
                opentags += 1

            elif char == ord(">"):
                # newline before > then dedent
                output.append((indent, current_line))
                current_line = bytearray()
                current_line.append(char)
                indent -= indent_per_level

                if opentags == 0:
                    print("ERR: have more closing > than opening ones!")

                opentags -= 1

            else:
                current_line.append(char)

    if current_line:
        output.append((indent, current_line))

    if opentags != 0:
        print("ERR: unbalanced < and > count!")

    for indent, line in output:
        if not args.no_color:
            color = str(31 + (indent//indent_per_level) % 8).encode()
            sys.stdout.buffer.write(b"\x1b[%sm" % color)

        for elem in (b" " * indent, line.strip(), b"\n"):
            sys.stdout.buffer.write(elem)

        if not args.no_color:
            sys.stdout.buffer.write(b"\x1b[m")


if __name__ == "__main__":
    main()