はてなブログ用のmarkdownで$$で囲まれた\、^、_をエスケープするためのスクリプト(正しく動いているかは不明)

hatena_latex_convert.py

#! /usr/bin/env python3
# -*- coding:utf-8 -*-
# 参考:http://d.hatena.ne.jp/greennoah/20090216/1234784592

import re
import sys
import os

# $...$で囲まれたインライン数式用の置換
def inline_replace(line):
    line = re.sub(r'\\(?=.*\$)', r'\\\\', line)
    line = re.sub(r'\^(?=.*\$)', r'\^', line)
    line = re.sub(r'_(?=.*\$)', r'\_', line)
    return line

# $$...$$で囲まれたブロック数式用の置換
def block_replace(line):
    line = re.sub(r'\\', r'\\\\', line)
    line = re.sub(r'\^', r'\^', line)
    line = re.sub(r'_', r'\_', line)
    return line

if len(sys.argv) < 1:
    print('Please input filename')
    sys.exit(0)

read_file = None
write_file = None
block_flag = False
temp_file = sys.argv[1].replace('.md', '')+'_convert.md'
try:
    read_file = open(sys.argv[1], 'r')
    write_file = open(temp_file, 'w')
    for line in read_file:
        if line.strip() == '$$':
            block_flag = not(block_flag)
        if block_flag:
            line = block_replace(line)
        else:
            line = inline_replace(line)
        write_file.write(line)
finally:
    read_file.close()
    write_file.close()

# if os.path.isfile(sys.argv[1]) and os.path.isfile(temp_file):
#     os.remove(sys.argv[1])
#     os.rename(temp_file, sys.argv[1])
sys.exit(0)