docs: public Token next() throws ScanException {
  		if (token != null) {
  			position += token.getSize();
  		}
  	
  		int length = input.length();
  				
  		if (isEval()) {
  			while (position < length && Character.isWhitespace(input.charAt(position))) {
  				position++;
  			}
  		}
  
  		if (position == length) {
  			return token = fixed(Symbol.EOF);
  		}
  
  		return token = nextToken();
  	}