@@ -289,6 +289,26 @@ class CodeBlockSpanNode extends InlineContentNode {
289289 }
290290}
291291
292+ class MathBlockNode extends BlockContentNode {
293+ const MathBlockNode ({super .debugHtmlNode, required this .texSource});
294+
295+ final String texSource;
296+
297+ @override
298+ bool operator == (Object other) {
299+ return other is MathBlockNode && other.texSource == texSource;
300+ }
301+
302+ @override
303+ int get hashCode => Object .hash ('MathBlockNode' , texSource);
304+
305+ @override
306+ void debugFillProperties (DiagnosticPropertiesBuilder properties) {
307+ super .debugFillProperties (properties);
308+ properties.add (StringProperty ('texSource' , texSource));
309+ }
310+ }
311+
292312class ImageNode extends BlockContentNode {
293313 const ImageNode ({super .debugHtmlNode, required this .srcUrl});
294314
@@ -493,6 +513,26 @@ class ImageEmojiNode extends EmojiNode {
493513 }
494514}
495515
516+ class MathInlineNode extends InlineContentNode {
517+ const MathInlineNode ({super .debugHtmlNode, required this .texSource});
518+
519+ final String texSource;
520+
521+ @override
522+ bool operator == (Object other) {
523+ return other is MathInlineNode && other.texSource == texSource;
524+ }
525+
526+ @override
527+ int get hashCode => Object .hash ('MathInlineNode' , texSource);
528+
529+ @override
530+ void debugFillProperties (DiagnosticPropertiesBuilder properties) {
531+ super .debugFillProperties (properties);
532+ properties.add (StringProperty ('texSource' , texSource));
533+ }
534+ }
535+
496536////////////////////////////////////////////////////////////////
497537
498538// Ported from https://github.com/zulip/zulip-mobile/blob/c979530d6804db33310ed7d14a4ac62017432944/src/emoji/data.js#L108-L112
@@ -532,6 +572,60 @@ class _ZulipContentParser {
532572 /// and should be read or updated only inside an assertion.
533573_ParserContext _debugParserContext = _ParserContext .block;
534574
575+ String ? parseMath (dom.Element element, {required bool block}) {
576+ assert (block == (_debugParserContext == _ParserContext .block));
577+
578+ final dom.Element katexElement;
579+ if (! block) {
580+ assert (element.localName == 'span'
581+ && element.classes.length == 1
582+ && element.classes.contains ('katex' ));
583+
584+ katexElement = element;
585+ } else {
586+ assert (element.localName == 'span'
587+ && element.classes.length == 1
588+ && element.classes.contains ('katex-display' ));
589+
590+ if (element.nodes.length != 1 ) return null ;
591+ final child = element.nodes.single;
592+ if (child is ! dom.Element ) return null ;
593+ if (child.localName != 'span' ) return null ;
594+ if (child.classes.length != 1 ) return null ;
595+ if (! child.classes.contains ('katex' )) return null ;
596+ katexElement = child;
597+ }
598+
599+ // Expect two children span.katex-mathml, span.katex-html .
600+ // For now we only care about the .katex-mathml .
601+ if (katexElement.nodes.isEmpty) return null ;
602+ final child = katexElement.nodes.first;
603+ if (child is ! dom.Element ) return null ;
604+ if (child.localName != 'span' ) return null ;
605+ if (child.classes.length != 1 ) return null ;
606+ if (! child.classes.contains ('katex-mathml' )) return null ;
607+
608+ if (child.nodes.length != 1 ) return null ;
609+ final grandchild = child.nodes.single;
610+ if (grandchild is ! dom.Element ) return null ;
611+ if (grandchild.localName != 'math' ) return null ;
612+ if (grandchild.attributes['display' ] != (block ? 'block' : null )) return null ;
613+ if (grandchild.namespaceUri != 'http://www.w3.org/1998/Math/MathML' ) return null ;
614+
615+ if (grandchild.nodes.length != 1 ) return null ;
616+ final greatgrand = grandchild.nodes.single;
617+ if (greatgrand is ! dom.Element ) return null ;
618+ if (greatgrand.localName != 'semantics' ) return null ;
619+
620+ if (greatgrand.nodes.isEmpty) return null ;
621+ final descendant4 = greatgrand.nodes.last;
622+ if (descendant4 is ! dom.Element ) return null ;
623+ if (descendant4.localName != 'annotation' ) return null ;
624+ if (descendant4.attributes['encoding' ] != 'application/x-tex' ) return null ;
625+
626+ return descendant4.text.trim ();
627+ }
628+
535629 /// The links found so far in the current block inline container.
536630 ///
537631 /// Empty is represented as null.
@@ -623,6 +717,14 @@ class _ZulipContentParser {
623717 return ImageEmojiNode (src: src, alt: alt, debugHtmlNode: debugHtmlNode);
624718 }
625719
720+ if (localName == 'span'
721+ && classes.length == 1
722+ && classes.contains ('katex' )) {
723+ final texSource = parseMath (element, block: false );
724+ if (texSource == null ) return unimplemented ();
725+ return MathInlineNode (texSource: texSource, debugHtmlNode: debugHtmlNode);
726+ }
727+
626728 // TODO more types of node
627729 return unimplemented ();
628730 }
@@ -792,6 +894,24 @@ class _ZulipContentParser {
792894 }
793895
794896 if (localName == 'p' && classes.isEmpty) {
897+ // Oddly, the way a math block gets encoded in Zulip HTML is inside a <p>.
898+ if (element.nodes case [dom.Element (localName: 'span' ) && var child, ...]) {
899+ if (child.classes.length == 1
900+ && child.classes.contains ('katex-display' )) {
901+ if (element.nodes case [_]
902+ || [_, dom.Element (localName: 'br' ),
903+ dom.Text (text: "\n " )]) {
904+ // This might be too specific; we'll find out when we do #190.
905+ // The case with the `<br>\n` can happen when at the end of a quote;
906+ // it seems like a glitch in the server's Markdown processing,
907+ // so hopefully there just aren't any further such glitches.
908+ final texSource = parseMath (child, block: true );
909+ if (texSource == null ) return UnimplementedBlockContentNode (htmlNode: node);
910+ return MathBlockNode (texSource: texSource, debugHtmlNode: debugHtmlNode);
911+ }
912+ }
913+ }
914+
795915 final parsed = parseBlockInline (element.nodes);
796916 return ParagraphNode (debugHtmlNode: debugHtmlNode,
797917 links: parsed.links,
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