centerblock.py

"""
This is Python Markdown extension that adds support for centered blocks similar to Vuepress.
"""

class CenterBlockProcessor(BlockProcessor):
    RE_START = r'^->'
    RE_END = r'<-$'

    def test(self, parent, block):
        return re.match(self.RE_START, block)

    def run(self, parent, blocks):
        original_block = blocks[0]
        blocks[0] = re.sub(self.RE_START, '', blocks[0])
        for block_num, block in enumerate(blocks):
            if re.search(self.RE_END, block):
                blocks[block_num] = re.sub(self.RE_END, '', block)
                e = etree.SubElement(parent, 'div')
                e.set('style', 'text-align:center')
                self.parser.parseBlocks(e, blocks[0:block_num + 1])
                for _ in range(0, block_num + 1):
                    blocks.pop(0)
                return True
        blocks[0] = original_block
        return False


class CenterBlockExtension(Extension):

    def extendMarkdown(self, md):  # noqa: N802
        md.parser.blockprocessors.register(
            CenterBlockProcessor(md.parser), 'centerblock', 175
        )