scribble-mathjax/unpacked/extensions/a11y/semantic-enrich.js

/*************************************************************
 *
 *  [Contrib]/a11y/semantic-enrich.js
 *  
 *  An extension that connects MathJax to the Speech-Rule-Engine
 *  to produce semantically enriched MathML.
 *
 *  ---------------------------------------------------------------------
 *  
 *  Copyright (c) 2016-2017 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.
 */

MathJax.Extension["semantic-enrich"] = {
  version: "1.2.2",
  config: MathJax.Hub.CombineConfig("semantic-enrich",{disabled: false}),
  dependents: [],     // the extensions that depend on this one
  running: false,
  //
  //  Names of attributes to force if set by mstyle
  //  (so SRE doesn't have to look these up)
  //
  mstyleLookup: {
    mi: ["mathvariant"],
    mo: ["mathvariant","accent","largeop","form","fence","separator","movablelimits"],
    mn: ["mathvariant"],
    mtext: ["mathvariant"],
    ms: ["mathvariant"],
    mfrac: ["linethickness"],
    mfenced: ["open","close","separators"],
    menclose: ["notation"],
    munder: ["accentunder"],
    mover: ["accent"],
    munderover: ["accent","accentunder"]
  },
  //
  //  If we are not disabled,
  //    Get the enriched MathML and parse it into the jax root.
  //    Mark the jax as enriched.
  //
  Filter: function (jax,id,script) {
    delete jax.enriched;
    if (this.config.disabled) return;
    try {
      this.running = true;
      var mml = sre.Enrich.semanticMathmlSync(jax.root.toMathML());
      jax.root = MathJax.InputJax.MathML.Parse.prototype.MakeMML(mml);
      jax.root.inputID = script.id;
      jax.enriched = true;
      this.running = false;
    } catch (err) {
      this.running = false;
      throw err;
    }
  },
  //
  //  Functions to enable and disabled enrichment.
  //
  Enable: function (update,menu) {
    this.config.disabled = false;
    if (update) MathJax.Hub.Queue(["Reprocess",MathJax.Hub]);
  },
  Disable: function (update,menu) {
    this.config.disabled = true;
    for (var i = this.dependents.length-1; i >= 0; i--) {
      var dependent = this.dependents[i];
      if (dependent.Disable) dependent.Disable(false,menu);
    }
    if (update) MathJax.Hub.Queue(["Reprocess",MathJax.Hub]);
  },
  
  //
  //  Register a dependent
  //
  Dependent: function (extension) {
    this.dependents.push(extension);
  }
};

(function () {
  //
  //  Set up the a11y path,if it isn't already in place
  //
  var PATH = MathJax.Ajax.config.path;
  if (!PATH.a11y) PATH.a11y = HUB.config.root + "/extensions/a11y";

  //
  //  Load SRE and use the signal to tell MathJax when it is loaded.
  //  Since SRE waits for the mml element jax, load that too.
  //
  if (!PATH.SRE) PATH.SRE = MathJax.Ajax.fileURL(PATH.a11y);
  MathJax.Ajax.Load("[SRE]/mathjax-sre.js");
  MathJax.Hub.Register.StartupHook("Sre Ready",["loadComplete",MathJax.Ajax,"[SRE]/mathjax-sre.js"]);
})();

//
//  Make a queue so that the MathML jax and SRE are both loaded before
//  we install the filter and signal that we are ready.  The MathML config.js
//  file must load before loading its jax.js file.
//
MathJax.Callback.Queue(
  //
  //  Load mml jax
  //
  ["Require",MathJax.Ajax,"[MathJax]/jax/element/mml/jax.js"],
  //
  //  Load MathML input jax (since we need Parse.MakeMML)
  //
  ["Require",MathJax.Ajax,"[MathJax]/jax/input/MathML/config.js"],
  ["Require",MathJax.Ajax,"[MathJax]/jax/input/MathML/jax.js"],
  //
  //  Load toMathML extension (if it isn't already)
  //
  ["Require",MathJax.Ajax,"[MathJax]/extensions/toMathML.js"],
  //
  //  Wait for SRE (which waits for mml jax) before modifying mbase
  //
  MathJax.Hub.Register.StartupHook("Sre Ready",function () {
    var MML = MathJax.ElementJax.mml,
        ENRICH = MathJax.Extension["semantic-enrich"];

    //
    //  Override toMathML's attribute function to include additional
    //  attributes inherited from mstyle (so SRE doesn't have to look them
    //  up itself).  Eventually, this should be moved to toMathML.js directly.
    //
    MML.mbase.Augment({
      toMathMLattributes: function () {
        var defaults = (this.type === "mstyle" ? MML.math.prototype.defaults : this.defaults);
        var names = (this.attrNames||MML.copyAttributeNames),
            skip = MML.skipAttributes, copy = MML.copyAttributes,
            lookup = (ENRICH.running ? ENRICH.mstyleLookup[this.type]||[] : []);
        var attr = [], ATTR = (this.attr||{});

        if (this.type === "math" && (!this.attr || !this.attr.xmlns))
          attr.push('xmlns="http://www.w3.org/1998/Math/MathML"');
        if (!this.attrNames) {
          for (var id in defaults) {if (!skip[id] && !copy[id] && defaults.hasOwnProperty(id)) {
            if (this[id] != null && this[id] !== defaults[id]) {
              if (this.Get(id,null,1) !== this[id]) this.toMathMLaddAttr(attr,id,this[id]);
            }
          }}
        }
        for (var i = 0, m = names.length; i < m; i++) {
          if (copy[names[i]] === 1 && !defaults.hasOwnProperty(names[i])) continue;
          value = ATTR[names[i]]; if (value == null) value = this[names[i]];
          if (value != null) this.toMathMLaddAttr(attr,names[i],value);
        }
        for (i = 0, m = lookup.length; i < m; i++) {
          id = lookup[i];
          if (defaults.hasOwnProperty(id) && !attr["_"+id]) {
            value = this.Get(id,1);
            if (value != null) this.toMathMLaddAttr(attr,id,value);
          }
        }
        this.toMathMLclass(attr);
        if (attr.length) return " "+attr.join(" "); else return "";
      },
      toMathMLaddAttr: function (attr,id,value) {
        attr.push(id+'="'+this.toMathMLquote(value)+'"');
        attr["_"+id] = 1;
      }
    });
  
    //
    //  Adjust setTeXclass for <mo> so that added elements don't
    //  cause unwanted space.
    //
    var TEXCLASS = MML.mo.prototype.setTeXclass;
    MML.mo.Augment({
      setTeXclass: function (prev) {
        var values = this.getValues("form","lspace","rspace"); // sets useMMLspacing
        if (this.useMMLspacing) {
          this.texClass = MML.TEXCLASS.NONE;
          return this;
        }
        if (this.attr && this.attr["data-semantic-added"]) {
          this.texClass = this.prevClass = MML.TEXCLASS.NONE;
          return prev;
        }
        return TEXCLASS.apply(this,arguments);
      }
    });
  }),
  function () {
    //
    //  Install enrichment filter, and signal that we are ready.
    //
    MathJax.Hub.postInputHooks.Add(["Filter",MathJax.Extension["semantic-enrich"]],50);
    MathJax.Hub.Startup.signal.Post("Semantic Enrich Ready");
    MathJax.Ajax.loadComplete("[a11y]/semantic-enrich.js");
  }
);