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Option / Some / None ​

The Option type models an optional value. Option is the abstract base class with the static factories, Some holds a value, and None represents the absence of one. All three implement Raxos\Foundation\Contract\OptionInterface.

See the Option type concept page for a guided introduction.

Option ​

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namespace Raxos\Foundation\Option;

abstract readonly class Option implements OptionInterface

Base class for optional values, extended by Some and None. It provides the static factories used to build options.

Static methods ​

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public static function some(mixed $value): OptionInterface

Returns a new Some wrapping the given value.

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public static function none(): OptionInterface

Returns the shared None instance.

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public static function fromValue(mixed $value, mixed $none = null): OptionInterface

Wraps a value in Some, or returns None if the value is identical to $none. If the value is already an option, it is returned as is.

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public static function fromCallable(callable $fn, mixed $none = null): OptionInterface

Calls the function and wraps the result via fromValue().

OptionInterface ​

The contract implemented by every option. Each method behaves differently for Some and None.

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public function get(): mixed;
public function getOrElse(mixed $fallback): mixed;
public function getOrInvoke(callable $fn): mixed;
public function getOrThrow(Throwable|callable $err): mixed;
public function map(callable $map): OptionInterface;
public function filter(callable $predicate): OptionInterface;
public function accept(mixed $value): OptionInterface;
public function reject(mixed $value): OptionInterface;
public function orElse(OptionInterface|callable $fallback): OptionInterface;
public function orThrow(Throwable|callable $err): OptionInterface;

Some ​

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namespace Raxos\Foundation\Option;

final readonly class Some extends Option implements DebuggableInterface

Represents an option that holds a value. Every accessor returns the wrapped value.

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public function get(): mixed

Returns the wrapped value.

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public function map(callable $map): Option

Applies the callable to the value and wraps the result in a new Some.

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public function filter(callable $predicate): OptionInterface

Returns itself if the predicate is true, otherwise None.

None ​

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namespace Raxos\Foundation\Option;

final readonly class None extends Option implements DebuggableInterface

Represents the absence of a value. Most accessors throw or fall back to a supplied default. None is created and shared through Singleton, so every Option::none() returns the same object.

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public function get(): mixed

Throws OptionException::noValue().

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public function getOrElse(mixed $fallback): mixed

Returns the given fallback value.

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public function getOrThrow(Throwable|callable $err): mixed

Throws the given exception, or the result of the given callable.

OptionException ​

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namespace Raxos\Foundation\Option;

final class OptionException extends Exception
  • OptionException::noValue(): thrown by None::get().
  • OptionException::notAnOption(): thrown by None::orElse() when a fallback callable does not return an OptionInterface.

Example ​

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<?php
declare(strict_types=1);

use Raxos\Foundation\Option\Option;

function findUser(int $id): OptionInterface
{
    return Option::fromValue(lookup($id));
}

$name = findUser(1)
    ->map(static fn(array $user): string => $user['name'])
    ->getOrElse('Guest');