TL;DR: Create a clear contract. Expect just one protocol.

문제

솔루션

샘플 코드

잘못된

<?

function parseArguments($arguments) {
    $arguments = $arguments ?: null;
    //Always the billion-dollar mistake
    if (is_empty($arguments)) {
        $this->arguments = http_build_query($_REQUEST);
        //Global coupling and side effects
    } elseif (is_array($arguments)) {
        $this->arguments = http_build_query($arguments);
    } elseif (!$arguments) { //null unmasked
        $this->arguments = null;
    } else {
        $this->arguments = (string)$arguments;
    }
}

오른쪽

<?

function parseArguments(array $arguments) {
    $this->arguments = $arguments;
    //much cleaner, isn't it ?
}

발각

태그

결론

처지

학점

Referential transparency is a very desirable property: it implies that functions consistently yield the same results given the same input, irrespective of where and when they are invoked.