text: module.exports = (function () {
    'use strict';
  
    var MoveError = function(px,py,zx,zy){
      this.message = 'Player('+px+','+py+') must be in same row or column as target zone('+zx+','+zy+').';
      this.stack = (new Error()).stack;
    };
  
    MoveError.prototype = new Error();
    MoveError.prototype.name = 'MoveError';
  
    return MoveError;
  
  })();