Add: initial prototype of Markdown in Doenet

packages/parser/src/dast-normalize/normalize-dast.ts

@@ -16,6 +16,11 @@ import { selectSugar } from "./component-sugar/select";
 import { postponeRenderSugar } from "./component-sugar/postponeRender";
 import { pluginEnforceValidNames } from "./enforce-valid-names";
 import { pretzelSugar } from "./component-sugar/pretzel";
+import { lezerToDast } from "../lezer-to-dast";
+import { Parser, HtmlRenderer } from "commonmark";
+
+const commonMarkParser = new Parser();
+const commonMarkRenderer = new HtmlRenderer();
 
 /**
  * Normalize the DAST tree so that it is contained in a single `<document>` element.
@@ -25,13 +30,15 @@ export function normalizeDocumentDast(
     dast: DastRoot,
     addCompatibilityNames = false,
 ) {
+    console.log(dast);
     let processor = unified()
         .use(pluginRemoveCommentsInstructionsAndDocStrings)
         .use(pluginChangeCdataToText)
         .use(pluginEnsureDocumentElement)
         .use(pluginConvertPretextAttributes)
         .use(pluginEnforceValidNames)
-        .use(pluginExpandAliasedElements);
+        .use(pluginExpandAliasedElements)
+        .use(pluginTextToMarkdown);
     if (addCompatibilityNames) {
         processor = processor.use(pluginAddCompatibilityNames);
     }
@@ -54,6 +61,29 @@ const pluginChangeCdataToText: Plugin<[], DastRoot, DastRoot> = () => {
     };
 };
 
+/**
+ * Interpret all text nodes that are children of the root node as Markdown, transforming them to HTML.
+ */
+const pluginTextToMarkdown: Plugin<[], DastRoot, DastRoot> = () => {
+    return (tree) => {
+        visit(tree, (node, visitInfo) => {
+            // All text nodes that are children of the root node are interpreted as Markdown.
+            if (node.type === "text" && visitInfo.parents.length === 1) {
+                const html = commonMarkRenderer.render(
+                    commonMarkParser.parse(node.value),
+                );
+                // Parse this HTML into a DAST tree, then replace the text node with the new DAST tree.
+                const dast = lezerToDast(html);
+                visitInfo.parents[0].children.splice(
+                    visitInfo.index!,
+                    1,
+                    ...(dast.children as DastElementContent[]),
+                );
+            }
+        });
+    };
+};
+
 /**
  * Remove all comment/instruction/docstring nodes from the DAST tree.
  */

packages/parser/test/dast-basic.test.ts

@@ -13,6 +13,7 @@ import {
     splitTextAtSpecialChars,
     splitTextNodeAt,
 } from "../src/lezer-to-dast/gobble-function-arguments";
+import { normalizeDocumentDast } from "../src/dast-normalize/normalize-dast";
 
 const origLog = console.log;
 console.log = (...args) => {
@@ -470,4 +471,14 @@ describe("DAST", async () => {
           }
         `);
     });
+    it("converts Markdown text to HTML", () => {
+        let source: string;
+        let dast: ReturnType<typeof lezerToDast>;
+
+        source = `*hi*\n\n# there!`;
+        dast = lezerToDast(source);
+        expect(toXml(normalizeDocumentDast(dast))).toEqual(
+            "<document><p><em>hi</em></p><h1>there!</h1></document>",
+        );
+    });
 });

packages/test-viewer/src/test/testCode.doenet

@@ -1,3 +1,5 @@
+**test**
+
 <graph>
     <point name="P" x="3" y="1" />
     <rectangle width="40" height="40" center="(0,0)" filled name="R" />
@@ -17,8 +19,8 @@
   <p>A lovely section.</p>
   <problem>
     <p>
-      This problem is nested inside a section. The default number does not
-      include the parent number.
+    This problem is nested inside a section. The default number does not
+    include the parent number.
     </p>
   </problem>
 </section>
@@ -27,8 +29,8 @@
   <p>Another section!</p>
   <problem includeParentNumber="true">
     <p>
-      This exercise is nested inside a section. Rendering of the parent section
-      number has been included.
+    This exercise is nested inside a section. Rendering of the parent section
+    number has been included.
     </p>
   </problem>
 </section>