Using logical operators such as and instead of && is generally not recommended.
PHP has two types of connecting operators (logical operators, and boolean operators):
Logical Operators
Boolean Operator
AND - meaning
and
&&
OR - meaning
or
||
The difference between these is the order in which they are executed. In most cases,
you would want to use a boolean operator like &&, or ||.
Let’s take a look at a few examples:
// Logical operators have lower precedence:$f=falseortrue;// is executed like this:($f=false)ortrue;// Boolean operators have higher precedence:$f=false||true;// is executed like this:$f=(false||true);
Logical Operators are used for Control-Flow
One case where you explicitly want to use logical operators is for control-flow
such as this:
$x===5ordie('$x must be 5.');// Instead ofif($x!==5){die('$x must be 5.');}
Since die introduces problems of its own, f.e. it makes our code hardly
testable, and prevents any kind of more sophisticated error handling; you probably
do not want to use this in real-world code. Unfortunately, logical operators
cannot be combined with throw at this point:
// The following is currently a parse error.$x===5orthrownewRuntimeException('$x must be 5.');
These limitations lead to logical operators rarely being of use in current
PHP code.
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// @todo make sure a new user is stored in Auth, otherwise
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// the access to the modules are not correctly maintained.
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// Right now I just clear permisions when getting the new user
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// which probably is the most clever solution.
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if ($this->getKernel()->user->setActiveIntranetId(intval($this->query('id')))) {
$this->db->query("SELECT DISTINCT(intranet.id), name FROM intranet INNER JOIN permission ON permission.intranet_id = intranet.id WHERE permission.user_id = " . $this->getKernel()->user->getId() . " ORDER BY name");
interfaceUser{/** @return string */publicfunctiongetPassword();}classMyUserimplementsUser{publicfunctiongetPassword(){// return something}publicfunctiongetDisplayName(){// return some name.}}classAuthSystem{publicfunctionauthenticate(User$user){$this->logger->info(sprintf('Authenticating %s.',$user->getDisplayName()));// do something.}}
In the above example, the authenticate() method works fine as long as you just pass
instances of MyUser. However, if you now also want to pass a different implementation
of User which does not have a getDisplayName() method, the code will break.
classAuthSystem{publicfunctionauthenticate(User$user){if($userinstanceofMyUser){$this->logger->info(/** ... */);}// or alternativelyif(!$userinstanceofMyUser){thrownew\LogicException('$user must be an instance of MyUser, '.'other instances are not supported.');}}}
Note: PHP Analyzer uses reverse abstract interpretation to narrow down the types
inside the if block in such a case.
intraface /
intraface.dk
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PHP has two types of connecting operators (logical operators, and boolean operators):
and&&or||The difference between these is the order in which they are executed. In most cases, you would want to use a boolean operator like
&&, or||.Let’s take a look at a few examples:
Logical Operators are used for Control-Flow
One case where you explicitly want to use logical operators is for control-flow such as this:
Since
dieintroduces problems of its own, f.e. it makes our code hardly testable, and prevents any kind of more sophisticated error handling; you probably do not want to use this in real-world code. Unfortunately, logical operators cannot be combined withthrowat this point:These limitations lead to logical operators rarely being of use in current PHP code.