code: public Token scanIndent() {
  		int start = pos;
  		while (pos < input.length()
  				&& (input.charAt(pos) == ' ' || input.charAt(pos) == '\t')) {
  			pos++;
  		}
  		return new Token(Token.Kind.Indent, input.substring(start, pos), start);
  	}
docs: Scan one or more spaces or tab characters, combining them to form an
  "indent".
  
  @return