Math/modules/MathJax/extensions/TeX/mathchoice.js

/*************************************************************
 *
 *  MathJax/extensions/TeX/mathchoice.js
 *  
 *  Implements the \mathchoice macro (rarely used)
 *
 *  ---------------------------------------------------------------------
 *  
 *  Copyright (c) 2009-2012 Design Science, Inc.
 * 
 *  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.Hub.Register.StartupHook("TeX Jax Ready",function () {
  var VERSION = "2.0";

  var MML = MathJax.ElementJax.mml;
  var TEX = MathJax.InputJax.TeX;
  var TEXDEF = TEX.Definitions;
  
  TEXDEF.macros.mathchoice = 'MathChoice';

  TEX.Parse.Augment({

    MathChoice: function (name) {
      var D  = this.ParseArg(name),
          T  = this.ParseArg(name),
          S  = this.ParseArg(name),
          SS = this.ParseArg(name);
      this.Push(MML.TeXmathchoice(D,T,S,SS));
    }

  });
  
  MML.TeXmathchoice = MML.mbase.Subclass({
    type: "TeXmathchoice",
    choice: function () {
      var values = this.getValues("displaystyle","scriptlevel");
      if (values.scriptlevel > 0) {return Math.min(3,values.scriptlevel + 1)}
      return (values.displaystyle ? 0 : 1);
    },
    setTeXclass: function (prev) {return this.Core().setTeXclass(prev)},
    isSpacelike: function () {return this.Core().isSpacelike()},
    isEmbellished: function () {return this.Core().isEmbellished()},
    Core: function () {return this.data[this.choice()]},
    toHTML: function (span) {
      span = this.HTMLcreateSpan(span);
      span.bbox = this.Core().toHTML(span).bbox;
      // Firefox doesn't correctly handle a span with a negatively sized content,
      //   so move marginLeft to main span (this is a hack to get \iiiint to work).
      //   FIXME:  This is a symptom of a more general problem with Firefox, and
      //           there probably needs to be a more general solution (e.g., modifying
      //           HTMLhandleSpace() to get the width and adjust the right margin to
      //           compensate for negative-width contents)
      if (span.firstChild && span.firstChild.style.marginLeft) {
        span.style.marginLeft = span.firstChild.style.marginLeft;
        span.firstChild.style.marginLeft = "";
      }
      return span;
    },
    toSVG: function () {return this.Core().toSVG()}
  });
  
  MathJax.Hub.Startup.signal.Post("TeX mathchoice Ready");
  
});

MathJax.Ajax.loadComplete("[MathJax]/extensions/TeX/mathchoice.js");