anchor.diff:  //List<_Token> scan(String source, bool lenient) => _scan(source, lenient);
   //List<_Token> trim(List<_Token> tokens) => _trim(tokens);
   
  -List<_Token> _scan(String source, bool lenient) //=> _trim(new _Scanner(source).scan());
  -{
  -	var tokens = new _Scanner(source).scan();
  -	tokens = _trim(tokens);	
  -	return tokens;
  -}
  +List<_Token> _scan(String source, bool lenient) => _trim(new _Scanner(source).scan());
   
   const int _TEXT = 1;
   const int _VARIABLE = 2;
  
positive.code: const int _EOF = -1;
  const int _TAB = 9;
  const int _NEWLINE = 10;
  const int _SPACE = 32;
  const int _EXCLAIM = 33;
  const int _QUOTE = 34;
  
negative.code: 			// Swallow line end.
  			assert(isLineEnd(peek()));
  			read();
  
  			standaloneLineCheck(); //FIXME don't use recursion.
  		}
  	}
  
  