import markdown
from markdown.inlinepatterns import SimpleTagPattern


STRIKETROUGH_RE = r'(~{2})(.+?)\2'


class StriketroughExtension(markdown.Extension):
    def extendMarkdown(self, md):
        md.registerExtension(self)
        md.inlinePatterns.add(
            'misago_striketrough', SimpleTagPattern(STRIKETROUGH_RE, 'del'), '_end')