Function ensureState

static/editor.md/lib/codemirror/addon/mode/simple.js:61–64

(states, name)

  };

  function ensureState(states, name) {
    if (!states.hasOwnProperty(name))
      throw new Error("Undefined state " + name + "in simple mode");
  }

  function toRegex(val, caret) {
    if (!val) return /(?:)/;