com/public/vendor/plugins/codemirror/mode/spreadsheet/spreadsheet.js

// CodeMirror, copyright (c) by Marijn Haverbeke and others
// Distributed under an MIT license: https://codemirror.net/LICENSE

(function(mod) {
  if (typeof exports == "object" && typeof module == "object") // CommonJS
    mod(require("../../lib/codemirror"));
  else if (typeof define == "function" && define.amd) // AMD
    define(["../../lib/codemirror"], mod);
  else // Plain browser env
    mod(CodeMirror);
})(function(CodeMirror) {
  "use strict";

  CodeMirror.defineMode("spreadsheet", function () {
    return {
      startState: function () {
        return {
          stringType: null,
          stack: []
        };
      },
      token: function (stream, state) {
        if (!stream) return;

        //check for state changes
        if (state.stack.length === 0) {
          //strings
          if ((stream.peek() == '"') || (stream.peek() == "'")) {
            state.stringType = stream.peek();
            stream.next(); // Skip quote
            state.stack.unshift("string");
          }
        }

        //return state
        //stack has
        switch (state.stack[0]) {
        case "string":
          while (state.stack[0] === "string" && !stream.eol()) {
            if (stream.peek() === state.stringType) {
              stream.next(); // Skip quote
              state.stack.shift(); // Clear flag
            } else if (stream.peek() === "\\") {
              stream.next();
              stream.next();
            } else {
              stream.match(/^.[^\\\"\']*/);
            }
          }
          return "string";

        case "characterClass":
          while (state.stack[0] === "characterClass" && !stream.eol()) {
            if (!(stream.match(/^[^\]\\]+/) || stream.match(/^\\./)))
              state.stack.shift();
          }
          return "operator";
        }

        var peek = stream.peek();

        //no stack
        switch (peek) {
        case "[":
          stream.next();
          state.stack.unshift("characterClass");
          return "bracket";
        case ":":
          stream.next();
          return "operator";
        case "\\":
          if (stream.match(/\\[a-z]+/)) return "string-2";
          else {
            stream.next();
            return "atom";
          }
        case ".":
        case ",":
        case ";":
        case "*":
        case "-":
        case "+":
        case "^":
        case "<":
        case "/":
        case "=":
          stream.next();
          return "atom";
        case "$":
          stream.next();
          return "builtin";
        }

        if (stream.match(/\d+/)) {
          if (stream.match(/^\w+/)) return "error";
          return "number";
        } else if (stream.match(/^[a-zA-Z_]\w*/)) {
          if (stream.match(/(?=[\(.])/, false)) return "keyword";
          return "variable-2";
        } else if (["[", "]", "(", ")", "{", "}"].indexOf(peek) != -1) {
          stream.next();
          return "bracket";
        } else if (!stream.eatSpace()) {
          stream.next();
        }
        return null;
      }
    };
  });

  CodeMirror.defineMIME("text/x-spreadsheet", "spreadsheet");
});