Source code for errbot.rendering

# vim: noai:ts=4:sw=4
import re

from markdown import Markdown
from markdown.extensions.extra import ExtraExtension

# Attribute regexp looks for extendend syntax: {: ... }
ATTR_RE = re.compile(r"{:([^}]*)}")
MD_ESCAPE_RE = re.compile(
    "|".join(
        re.escape(c)
        for c in (
            "\\",
            "`",
            "*",
            "_",
            "{",
            "}",
            "[",
            "]",
            "(",
            ")",
            ">",
            "#",
            "+",
            "-",
            ".",
            "!",
        )
    )
)

# Here are few helpers to simplify the conversion from markdown to various
# backend formats.




def ansi():
    """This makes a converter from markdown to ansi (console) format.
    It can be called like this:
    from errbot.rendering import ansi
    md_converter = ansi()  # you need to cache the converter

    ansi_txt = md_converter.convert(md_txt)
    """
    from .ansiext import AnsiExtension

    md = Markdown(output_format="ansi", extensions=[ExtraExtension(), AnsiExtension()])
    md.stripTopLevelTags = False
    return md





def text():
    """This makes a converter from markdown to text (unicode) format.
    It can be called like this:
    from errbot.rendering import text
    md_converter = text()  # you need to cache the converter

    pure_text = md_converter.convert(md_txt)
    """
    from .ansiext import AnsiExtension

    md = Markdown(output_format="text", extensions=[ExtraExtension(), AnsiExtension()])
    md.stripTopLevelTags = False
    return md





def imtext():
    """This makes a converter from markdown to imtext (unicode) format.
    imtest is the format like gtalk, slack or skype with simple _ or * markup.

    It can be called like this:
    from errbot.rendering import imtext
    md_converter = imtext()  # you need to cache the converter

    im_text = md_converter.convert(md_txt)
    """
    from .ansiext import AnsiExtension

    md = Markdown(
        output_format="imtext", extensions=[ExtraExtension(), AnsiExtension()]
    )
    md.stripTopLevelTags = False
    return md





class Mde2mdConverter:


    def convert(self, mde):
        while True:
            m = ATTR_RE.search(mde)
            if m is None:
                break
            left, right = m.span()
            mde = mde[:left] + mde[right:]
        return mde






def md():
    """This makes a converter from markdown-extra to markdown, stripping the attributes from extra."""
    return Mde2mdConverter()





def xhtml():
    """This makes a converter from markdown to xhtml format.
    It can be called like this:
    from errbot.rendering import xhtml
    md_converter = xhtml()  # you need to cache the converter

    html = md_converter.convert(md_txt)
    """
    return Markdown(output_format="xhtml", extensions=[ExtraExtension()])





def md_escape(txt):
    """Call this if you want to be sure your text won't be interpreted as markdown
    :param txt: bare text to escape.
    """
    return MD_ESCAPE_RE.sub(lambda match: "\\" + match.group(0), txt)