stuff

node_modules/mathjax-full/ts/input/mathml/mml3/mml3-node.ts

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+/*************************************************************
+ *
+ *  Copyright (c) 2021-2022 The MathJax Consortium
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+
+/**
+ * @fileoverview  Auxiliary function for elementary MathML3 support (experimental)
+ *                using David Carlisle's XLST transform.
+ *
+ * @author dpvc@mathjax.org (Davide Cervone)
+ */
+
+import {MathDocument} from '../../../core/MathDocument.js';
+
+/**
+ * Create the transform function that uses Saxon-js to perform the
+ *   xslt transformation.
+ *
+ * @template N  The HTMLElement node class
+ * @template T  The Text node class
+ * @template D  The Document class
+ *
+ * @return {(node: N, doc: MathDocument<N,T,D>) => N)}   The transformation function
+ */
+export function createTransform<N, T, D>(): (node: N, doc: MathDocument<N, T, D>) => N {
+  /* tslint:disable-next-line:no-eval */
+  const nodeRequire = eval('require');   // get the actual require from node.
+  /* tslint:disable-next-line:no-eval */
+  const dirname = eval('__dirname');     // get the actual __dirname
+  try {
+    nodeRequire.resolve('saxon-js');     // check if saxon-js is installed.
+  } catch (err) {
+    throw Error('Saxon-js not found.  Run the command:\n    npm install saxon-js\nand try again.');
+  }
+  const Saxon = nodeRequire('saxon-js'); // dynamically load Saxon-JS.
+  const path = nodeRequire('path');      // use the real version from node.
+  const fs = nodeRequire('fs');          // use the real version from node.
+  const xsltFile = path.resolve(dirname, 'mml3.sef.json');  // load the preprocessed stylesheet.
+  const xslt = JSON.parse(fs.readFileSync(xsltFile));       // and parse it.
+  return (node: N, doc: MathDocument<N, T, D>) => {
+    const adaptor = doc.adaptor;
+    let mml = adaptor.outerHTML(node);
+    //
+    //  Make sure the namespace is present
+    //
+    if (!mml.match(/ xmlns[=:]/)) {
+      mml = mml.replace(/<(?:(\w+)(:))?math/, '<$1$2math xmlns$2$1="http://www.w3.org/1998/Math/MathML"');
+    }
+    //
+    //  Try to run the transform, and if it fails, return the original MathML
+    //
+    let result;
+    try {
+      result = adaptor.firstChild(adaptor.body(adaptor.parse(Saxon.transform({
+        stylesheetInternal: xslt,
+        sourceText: mml,
+        destination: 'serialized'
+      }).principalResult))) as N;
+    } catch (err) {
+      result = node;
+    }
+    return result;
+  };
+}