add initial marp implementation with sample content and build configuration

node_modules/katex/src/functions/htmlmathml.js

@@ -0,0 +1,34 @@
+// @flow
+import defineFunction, {ordargument} from "../defineFunction";
+import buildCommon from "../buildCommon";
+
+import * as html from "../buildHTML";
+import * as mml from "../buildMathML";
+
+defineFunction({
+    type: "htmlmathml",
+    names: ["\\html@mathml"],
+    props: {
+        numArgs: 2,
+        allowedInText: true,
+    },
+    handler: ({parser}, args) => {
+        return {
+            type: "htmlmathml",
+            mode: parser.mode,
+            html:   ordargument(args[0]),
+            mathml: ordargument(args[1]),
+        };
+    },
+    htmlBuilder: (group, options) => {
+        const elements = html.buildExpression(
+            group.html,
+            options,
+            false
+        );
+        return buildCommon.makeFragment(elements);
+    },
+    mathmlBuilder: (group, options) => {
+        return mml.buildExpressionRow(group.mathml, options);
+    },
+});