Fix and catch speech computation errors, add missing braille option

package.json

@@ -141,6 +141,6 @@
     "mathjax-modern-font": "^4.0.0-beta.4",
     "mhchemparser": "^4.2.1",
     "mj-context-menu": "^0.9.1",
-    "speech-rule-engine": "^4.1.0-beta.7"
+    "speech-rule-engine": "^4.1.0-beta.8"
   }
 }

ts/a11y/explorer/KeyExplorer.ts

@@ -309,6 +309,13 @@ export class SpeechExplorer extends AbstractExplorer<string> implements KeyExplo
     return parent && this.highlighter.isMactionNode(parent) ? parent : null;
   }
 
+  /**
+   * Computes the nesting depth announcement for the currently focused sub
+   * expression.
+   *
+   * @param {HTMLElement} node The current node.
+   * @return {HTMLElement} The refocused node.
+   */
   public depth(node: HTMLElement): HTMLElement {
     this.generators.depth(node, !!this.actionable(node));
     this.refocus(node);

ts/a11y/semantic-enrich.ts

@@ -244,12 +244,21 @@ export function EnrichedMathItemMixin<N, T, D, B extends Constructor<AbstractMat
      */
     public attachSpeech(document: MathDocument<N, T, D>) {
       if (this.state() >= STATE.ATTACHSPEECH) return;
+      if (this.isEscaped || !document.options.enableEnrichment) {
+        this.state(STATE.ATTACHSPEECH);
+        return;
+      }
       let [speech, braille] = this.existingSpeech();
       let [newSpeech, newBraille] = ['', ''];
-      if (!speech || !braille ||
-        document.options.enableSpeech || document.options.enableBraille) {
-        [newSpeech, newBraille] = this.generatorPool.computeSpeech(
-          this.typesetRoot, this.toMathML(this.root, this));
+      if ((!speech && document.options.enableSpeech) ||
+        (!braille && document.options.enableBraille)) {
+        try {
+          [newSpeech, newBraille] = this.generatorPool.computeSpeech(
+            this.typesetRoot, this.toMathML(this.root, this));
+          if (newSpeech) {
+            newSpeech = buildSpeech(newSpeech)[0];
+          }
+        } catch (_e) { }
       }
       speech = speech || newSpeech;
       braille = braille || newBraille;
@@ -273,29 +282,6 @@ export function EnrichedMathItemMixin<N, T, D, B extends Constructor<AbstractMat
       this.state(STATE.ATTACHSPEECH);
     }
 
-    /**
-     * Retrieves the actual speech element that should be used as aria label.
-     * @param {MmlNode} node The root node to search from.
-     * @return {string} The speech content.
-     */
-    protected getSpeech(node: MmlNode): string {
-      const attributes = node.attributes;
-      if (!attributes) return '';
-      const speech = attributes.getExplicit('data-semantic-speech') as string;
-      // TODO (explorer) For tree role move all speech etc. to container
-      // element.
-      if (!attributes.hasExplicit('data-semantic-parent') && speech) {
-        return speech;
-      }
-      for (let child of node.childNodes) {
-        let value = this.getSpeech(child);
-        if (value) {
-          return value;
-        }
-      }
-      return '';
-    }
-
   };
 
 }
@@ -359,6 +345,7 @@ export function EnrichedMathDocumentMixin<N, T, D, B extends MathDocumentConstru
       ...BaseDocument.OPTIONS,
       enableEnrichment: true,
       enableSpeech: true,
+      enableBraille: true,
       enrichError: (doc: EnrichedMathDocument<N, T, D>,
                     math: EnrichedMathItem<N, T, D>,
                     err: Error) => doc.enrichError(doc, math, err),
@@ -404,8 +391,10 @@ export function EnrichedMathDocumentMixin<N, T, D, B extends MathDocumentConstru
      */
     public attachSpeech() {
       if (!this.processed.isSet('attach-speech')) {
-        for (const math of this.math) {
-          (math as EnrichedMathItem<N, T, D>).attachSpeech(this);
+        if (this.options.enableSpeech || this.options.enableBraille) {
+          for (const math of this.math) {
+            (math as EnrichedMathItem<N, T, D>).attachSpeech(this);
+          }
         }
         this.processed.set('attach-speech');
       }

ts/a11y/speech/GeneratorPool.ts

@@ -394,7 +394,7 @@ export class GeneratorPool<N, T, D> {
       this.CleanUp(node);
       return this.lastSpeech;
     }
-    let postfix = this.summaryGenerator.getExpandable(
+    let postfix = this.summaryGenerator.getActionable(
       actionable ?
         (this.adaptor.childNodes(node).length === 0 ? -1 : 1)
         : 0);