beginnings of callout support

src/dragonglass/mparse.py

@@ -13,7 +13,7 @@ from urllib.parse import urlparse
 
 import markdown
 from markdown import Markdown
-from markdown.blockprocessors import BlockProcessor, BlockParser
+from markdown.blockprocessors import BlockProcessor, BlockParser, BlockQuoteProcessor
 from markdown.extensions import Extension
 from markdown.extensions.footnotes import (FootnoteExtension, FootnoteBlockProcessor, FootnoteInlineProcessor,
                                            FootnoteTreeprocessor, FootnotePostTreeprocessor, FootnotePostprocessor)
@@ -861,6 +861,71 @@ class ObsidianStyleFootnotes(FootnoteExtension):
         md.postprocessors.register(FootnotePostprocessor(self), 'footnote', 25)
 
 
+class ObsidianStyleBlockquotes(Extension):
+
+    class ObsidianBlockQuote(BlockQuoteProcessor):
+        CALLOUT = re.compile(r'^\[!([a-z]+)\]([-+])?(?:[ ]+(.*))?')
+
+        def normal_blockquote(self, parent: etree.Element, block: str) -> None:
+            sibling = self.lastChild(parent)
+            if sibling is not None and sibling.tag == "blockquote":
+                # Previous block was a blockquote so set that as this blocks parent
+                quote = sibling
+            else:
+                # This is a new blockquote. Create a new parent element.
+                quote = etree.SubElement(parent, 'blockquote')
+            # Recursively parse block with blockquote as parent.
+            # change parser state so blockquotes embedded in lists use `p` tags
+            self.parser.state.set('blockquote')
+            self.parser.parseChunk(quote, block)
+            self.parser.state.reset()
+
+        def callout_block(self, parent: etree.Element, lines: list[str]) -> None:
+            m = self.CALLOUT.match(lines[0])
+            callout_type = m.group(1)
+            # folding = m.group(2)
+            title = m.group(3)
+            if not title:
+                title = callout_type.title()
+            base_div = etree.SubElement(parent, 'div', {'class': 'callout', 'data-callout': callout_type})
+            title_div = etree.SubElement(base_div, 'div', {'class': 'callout-title'})
+            # TODO: add title icon here
+            inner_title_div = etree.SubElement(title_div, 'div', {'class': 'callout-title-inner'})
+            inner_title_div.text = title
+            content_div = etree.SubElement(base_div, 'div', {'class': 'callout-content'})
+            lines.pop(0)
+            first = True
+            for line in lines:
+                if first:
+                    first = False
+                else:
+                    etree.SubElement(content_div, 'br')
+                self.parser.state.set('list')
+                self.parser.parseBlocks(content_div, [line])
+                self.parser.state.reset()
+
+        def run(self, parent: etree.Element, blocks: list[str]) -> None:
+            block = blocks.pop(0)
+            lines: list[str] = []
+            callout = False
+            m = self.RE.search(block)
+            if m:
+                before = block[:m.start()]  # Lines before blockquote
+                # Pass lines before blockquote in recursively for parsing first.
+                self.parser.parseBlocks(parent, [before])
+                # Remove `> ` from beginning of each line.
+                lines = [self.clean(line) for line in block[m.start():].split('\n')]
+                callout = (self.CALLOUT.match(lines[0]) is not None)
+                block = '\n'.join(lines)
+            if callout:
+                self.callout_block(parent, lines)
+            else:
+                self.normal_blockquote(parent, block)
+
+    def extendMarkdown(self, md) -> None:
+        md.parser.blockprocessors.register(ObsidianStyleBlockquotes.ObsidianBlockQuote(md.parser), 'quote', 20)
+
+
 def create_markdown_parser(context: Context) -> markdown.Markdown:
     """
     Creates a Markdown parser with all our extensions loaded.
@@ -887,6 +952,7 @@ def create_markdown_parser(context: Context) -> markdown.Markdown:
                                          MetaStripper(),
                                          ObsidianComments(),
                                          ObsidianStyleFootnotes(SUPERSCRIPT_TEXT='[{}]', SEPARATOR='-'),
+                                         ObsidianStyleBlockquotes(),
                                          ObsidianImages(context),
                                          ObsidianLinks(context),
                                          ObsidianLists(),