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"
        )