code: function () {
                      var value, c = input.charCodeAt(i);
                      if ((c > 57 || c < 45) || c === 47) return;
  
                      if (value = $(/^(-?\d*\.?\d+)(px|%|em|pc|ex|in|deg|s|ms|pt|cm|mm|rad|grad|turn|dpi|dpcm|dppx|rem|vw|vh|vmin|vm|ch)?/)) {
                          return new(tree.Dimension)(value[1], value[2]);
                      }
                  }
docs: A Dimension, that is, a number and a unit  0.5em 95%