PHP RFC: Return, break and continue expressions

• Version: 0.1
• Date: 2025-02-02
• Author: Dmitrii Derepko, xepozzd@gmail.com
• Status: Draft

Allows to write return, break and continue with any conditions, shrinking long conditions.

You would be able to make such constructions as:

• Nullable action
  • $value = $nullableValue ?? return; or break or continue
  • $element = $element->getParent() ?? return; or break or continue
• Otherwise action
  • $condition ?: return; or break or continue
  • $var = $condition ? $value ? return false; or break or continue

That would make these constructions be consistent with current throws flow, which is possible to use in any cases above.

4 years ago there was proposal https://wiki.php.net/rfc/throw_expression about making “throws” statement as an expression, that gave users an ability to write some “guarding” constructions shortly.

This is another one round to make the whole PHP be more consistent: Making return, break and continue control operators be able to use as an expression.

while ($condition) {
    $currentElement = $currentElement->getParent() ?? break; // is a new way
    // $currentElement = $currentElement->getParent(); 
    // if ($currentElement == null) return; // is an old way
    ....
}

function doSmth($nullableValue) {
    $value = $nullableValue ?? return; // is a new way
    // $value = $nullableValue;
    // if ($value == null) return; // is an old way
    ....
}

function doSmth($value) {
    guard($value) ?: return; // is a new way
    // if (guard($value)) return; // is an old way
    ....
}

function doSmth(MyInterface $value) {
    $value instanceof MyImplementation ?: return; // is a new way
    // if (!$value instanceof MyImplementation) return; // is an old way
    ....
}

function doSmth(int $value) {
    $value >= 0 ?: return; // is a new way
    // if ($value < 0) return; // is an old way
    ....
}

Typical “early return” cases in some instructions with state preparations:

New way:

function doSmth($id): Result {
    $user = $this->finder->findUserById($id) ?? return null;
    $account = $this->finder->findAccountByUserId($user->id) ?? return null;
 
    $result = $this->doSmthInternal($user, $account) ?: return Result::internalError();
 
    return $result->isOk ? Result::success($result->resultJson) : Result::error($result->errorText);
}

Old way:

function doSmth($id): Result {
    $user = $this->finder->findUserById($id);
    if ($user === null) {
        return null;
    }
    $account = $this->finder->findAccountByUserId($user->id);
    if ($account === null) {
        return null;
    }
 
    $result = $this->doSmthInternal($user, $account);
    if ($result === null) {
        return Result::internalError();
    }
 
    return $result->isOk ? Result::success($result->resultJson) : Result::error($result->errorText);
}

One more interesting point that the most PHP codestyle variations translate one-liner if ($cond) return; into 3 lines.

Fully compatible

===== Proposed PHP Version(s) ===== next PHP 8.5 or next PHP 9.x versions

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https://news-web.php.net/php.internals/122253

https://github.com/php/php-src/pull/17647

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