code: func parseNumber(tok *lexer.Token) (result float64, isInt bool) {
  	var valInt int
  	var err error
  
  	valInt, err = strconv.Atoi(tok.Val)
  	if err == nil {
  		isInt = true
  
  		result = float64(valInt)
  	} else {
  		isInt = false
  
  		result, err = strconv.ParseFloat(tok.Val, 64)
  		if err != nil {
  			errToken(tok, fmt.Sprintf("Failed to parse number: %s", tok.Val))
  		}
  	}
  
  	// named returned values
  	return
  }
docs: // parseNumber parses a number