Function indexOf

static/editor.md/lib/codemirror/addon/mode/multiplex.js:19–23

(string, pattern, from)

  var n_others = others.length;

  function indexOf(string, pattern, from) {
    if (typeof pattern == "string") return string.indexOf(pattern, from);
    var m = pattern.exec(from ? string.slice(from) : string);
    return m ? m.index + from : -1;
  }

  return {
    startState: function() {