README.md

Is operator for PHP

Plugin for the XP Compiler which adds an is operator to the PHP language.

Before

A mix of functions, syntax and XP core functionality is():

is_string($value)                                  // for primitives, use is_[T]()
is_callable($value)                                // for pseudo types callable, array, object
is_array($value) || $value instanceof \Traversable // no is_iterable in PHP 5 and 7.0 
$value instanceof Date                             // for value types
null === $value || is_int($value)                  // nullable types cannot be tested directly
is('[:string]', $value)                            // for types beyond PHP type system
is('string|util.URI', $value)                      // for types beyond PHP type system

After

Anything that works as a parameter, property or return type can be used with the is operator.

$value is string
$value is callable
$value is iterable
$value is Date
$value is ?int
$value is array<string, string>
$value is string|URI

Installation

After installing the XP Compiler into your project, also include this plugin.

$ composer require xp-framework/compiler
# ...

$ composer require xp-lang/php-is-operator
# ...

No further action is required.

See also

• https://wiki.php.net/rfc/pattern-matching
• https://docs.hhvm.com/hack/expressions-and-operators/is
• https://kotlinlang.org/docs/reference/typecasts.html
• https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/is
• https://externals.io/message/120655 (Proposal to introduce is operator)