from typing import Any, List, Mapping, Optional, Tuple from xml.etree.ElementTree import Element, SubElement import markdown from markdown.extensions import Extension from typing_extensions import override from zerver.lib.markdown import ResultWithFamily, walk_tree_with_family from zerver.lib.markdown.priorities import PREPROCESSOR_PRIORITES class NestedCodeBlocksRenderer(Extension): @override def extendMarkdown(self, md: markdown.Markdown) -> None: md.treeprocessors.register( NestedCodeBlocksRendererTreeProcessor(md, self.getConfigs()), "nested_code_blocks", PREPROCESSOR_PRIORITES["nested_code_blocks"], ) class NestedCodeBlocksRendererTreeProcessor(markdown.treeprocessors.Treeprocessor): def __init__(self, md: markdown.Markdown, config: Mapping[str, Any]) -> None: super().__init__(md) @override def run(self, root: Element) -> None: code_tags = walk_tree_with_family(root, self.get_code_tags) nested_code_blocks = self.get_nested_code_blocks(code_tags) for block in nested_code_blocks: tag, text = block.result codehilite_block = self.get_codehilite_block(text) self.replace_element(block.family.grandparent, codehilite_block, block.family.parent) def get_code_tags(self, e: Element) -> Optional[Tuple[str, Optional[str]]]: if e.tag == "code": return (e.tag, e.text) return None def get_nested_code_blocks( self, code_tags: List[ResultWithFamily[Tuple[str, Optional[str]]]], ) -> List[ResultWithFamily[Tuple[str, Optional[str]]]]: nested_code_blocks = [] for code_tag in code_tags: parent: Any = code_tag.family.parent grandparent: Any = code_tag.family.grandparent if ( parent.tag == "p" and grandparent.tag == "li" and parent.text is None and len(parent) == 1 and sum(1 for text in parent.itertext()) == 1 ): # if the parent (
) has no text, and no children,
# that means that the element inside is its
# only thing inside the bullet, we can confidently say
# that this is a nested code block
nested_code_blocks.append(code_tag)
return nested_code_blocks
def get_codehilite_block(self, code_block_text: Optional[str]) -> Element:
div = Element("div")
div.set("class", "codehilite")
pre = SubElement(div, "pre")
pre.text = code_block_text
return div
def replace_element(
self,
parent: Optional[Element],
replacement: Element,
element_to_replace: Element,
) -> None:
if parent is None:
return
for index, child in enumerate(parent):
if child is element_to_replace:
parent.insert(index, replacement)
parent.remove(element_to_replace)
def makeExtension(*args: Any, **kwargs: str) -> NestedCodeBlocksRenderer:
return NestedCodeBlocksRenderer(**kwargs)