Add client-side rendering option for Markdown pane based on MyST

panel/_templates/autoload_panel_js.js

@@ -182,7 +182,7 @@ calls it with the rendered model.
       console.debug("Bokeh: injecting script tag for BokehJS library: ", url);
       element.textContent = `
       import ${name} from "${url}"
-      window.${name} = ${name}
+      window.${name.replace('* as ', '')} = ${name.replace('* as ', '')}
       window._bokeh_on_load()
       `
       document.head.appendChild(element);

panel/_templates/js_resources.html

@@ -28,7 +28,7 @@
 {%- for name, file in js_module_exports.items() %}
 <script type="module">
   import {{ name }} from "{% if not file.startswith('http') %}./{% endif %}{{ file }}";
-  window.{{ name }} = {{ name }}
+  window.{{ name.replace('* as ', '') }} = {{ name.replace('* as ', '') }}
 </script>
 {%- endfor %}
 

panel/config.py

@@ -668,6 +668,7 @@ class panel_extension(_pyviz_extension):
         'jsoneditor': 'panel.models.jsoneditor',
         'katex': 'panel.models.katex',
         'mathjax': 'panel.models.mathjax',
+        'myst': 'panel.models.myst',
         'perspective': 'panel.models.perspective',
         'plotly': 'panel.models.plotly',
         'tabulator': 'panel.models.tabulator',
@@ -689,6 +690,7 @@ class panel_extension(_pyviz_extension):
         'gridstack': ['GridStack'],
         'katex': ['katex'],
         'mathjax': ['MathJax'],
+        'myst': ['mystparser'],
         'perspective': ["customElements.get('perspective-viewer')"],
         'plotly': ['Plotly'],
         'tabulator': ['Tabulator'],

panel/dist/css/markdown.css

@@ -317,7 +317,8 @@ h2:hover a.header-anchor::before {
   visibility: visible;
 }
 
-.codehilite {
+.codehilite,
+pre > code.hljs {
   padding: 1rem 1.25rem;
   margin-top: 1rem;
   margin-bottom: 1rem;
@@ -341,6 +342,7 @@ pre {
 }
 
 .codehilite > pre > code,
-.codehilite > code {
+.codehilite > code,
+pre > code.hljs {
   white-space: break-spaces;
 }

panel/models/html.ts

@@ -181,7 +181,7 @@ export class HTMLView extends PanelMarkupView {
     return processed_text.join("")
   }
 
-  private contains_tex(html: string): boolean {
+  contains_tex(html: string): boolean {
     if (!this.provider.MathJax) {
       return false
     }

panel/models/index.ts

@@ -27,6 +27,7 @@ export {JSONEditor} from "./jsoneditor"
 export {KaTeX} from "./katex"
 export {Location} from "./location"
 export {MathJax} from "./mathjax"
+export {MyST} from "./myst"
 export {PDF} from "./pdf"
 export {Perspective} from "./perspective"
 export {Player} from "./player"

panel/models/myst.py

@@ -0,0 +1,37 @@
+from ..config import config
+from ..io.resources import bundled_files
+from ..util import classproperty
+from .markup import HTML
+
+
+class MyST(HTML):
+    """
+    A bokeh model to render MyST markdown on the client side
+    """
+
+    __javascript_module_exports__ = ['* as mystparser', '* as myst2html']
+
+    __javascript_modules_raw__ = [
+        f"{config.npm_cdn}/[email protected]/+esm",
+        f"{config.npm_cdn}/[email protected]/+esm"
+    ]
+
+    @classproperty
+    def __javascript_modules__(cls):
+        return bundled_files(cls, 'javascript_modules')
+
+    __javascript_raw__ = [
+        'https://cdn.jsdelivr.net/gh/highlightjs/[email protected]/build/highlight.min.js'
+    ]
+
+    @classproperty
+    def __javascript__(cls):
+        return bundled_files(cls)
+
+    __css_raw__ = [
+        'https://cdn.jsdelivr.net/gh/highlightjs/[email protected]/build/styles/github-dark.min.css'
+    ]
+
+    @classproperty
+    def __css__(cls):
+        return bundled_files(cls, 'css')

panel/models/myst.ts

@@ -0,0 +1,60 @@
+import type * as p from "@bokehjs/core/properties"
+import {HTMLView, HTML} from "./html"
+
+export class MySTView extends HTMLView {
+  declare model: MyST
+
+  override set_html(html: string | null): void {
+    super.set_html(html)
+    for (const el of this.container.querySelectorAll("pre code")) {
+      (window as any).hljs.highlightElement(el)
+    }
+  }
+
+  override process_tex(): string {
+    const parsed = (window as any).mystparser.mystParse(this.model.text)
+    const text = (window as any).myst2html.mystToHtml(parsed)
+    if (this.model.disable_math || !this.contains_tex(text)) {
+      return text
+    }
+
+    const tex_parts = this.provider.MathJax.find_tex(text)
+    const processed_text: string[] = []
+
+    let last_index: number | undefined = 0
+    for (const part of tex_parts) {
+      processed_text.push(text.slice(last_index, part.start.n))
+      processed_text.push(this.provider.MathJax.tex2svg(part.math, {display: part.display}).outerHTML)
+
+      last_index = part.end.n
+    }
+
+    if (last_index! < text.length) {
+      processed_text.push(text.slice(last_index))
+    }
+
+    return processed_text.join("")
+  }
+}
+
+export namespace MyST {
+  export type Attrs = p.AttrsOf<Props>
+  export type Props = HTML.Props
+}
+
+export interface MyST extends MyST.Attrs {}
+
+export class MyST extends HTML {
+  declare properties: MyST.Props
+
+  constructor(attrs?: Partial<MyST.Attrs>) {
+    super(attrs)
+  }
+
+  static override __module__ = "panel.models.myst"
+
+  static {
+    this.prototype.default_view = MySTView
+    this.define<MyST.Props>(({}) => ({}))
+  }
+}

panel/pane/markup.py

@@ -14,9 +14,13 @@
 
 import param  # type: ignore
 
+from pyviz_comms import JupyterComm
+
 from ..io.resources import CDN_DIST
 from ..models.markup import HTML as _BkHTML, JSON as _BkJSON, HTMLStreamEvent
-from ..util import HTML_SANITIZER, escape, prefix_length
+from ..util import (
+    HTML_SANITIZER, escape, lazy_load, prefix_length,
+)
 from .base import ModelPane
 
 if TYPE_CHECKING:
@@ -361,7 +365,7 @@ class Markdown(HTMLBasePane):
         Additional markdown-it-py plugins to use.""")
 
     renderer = param.Selector(default='markdown-it', objects=[
-        'markdown-it', 'myst', 'markdown'], doc="""
+        'markdown-it', 'myst', 'markdown', 'mystjs'], doc="""
         Markdown renderer implementation.""")
 
     renderer_options = param.Dict(default={}, nested_refs=True, doc="""
@@ -449,6 +453,8 @@ def hilite(token, langname, attrs):
         return parser
 
     def _transform_object(self, obj: Any) -> dict[str, Any]:
+        if self.renderer == 'mystjs':
+            return dict(object=obj)
         import markdown
         if obj is None:
             obj = ''
@@ -482,6 +488,18 @@ def _process_param_change(self, params):
             params['css_classes'] = ['markdown'] + params['css_classes']
         return super()._process_param_change(params)
 
+    def _get_model(
+        self, doc: Document, root: Model | None = None,
+        parent: Model | None = None, comm: Comm | None = None
+    ) -> Model:
+        if self.renderer == 'mystjs':
+            self._bokeh_model = lazy_load(
+                'panel.models.myst', 'MyST', isinstance(comm, JupyterComm), root
+            )
+        else:
+            self._bokeh_model = _BkHTML
+        model = super()._get_model(doc, root, parent, comm)
+        return model
 
 
 class JSON(HTMLBasePane):