Option

Option<T> represents a value that may or may not exist — Some(value) or None — replacing null checks with an explicit, chainable API.

Creating an Option

use Maybe\Option\Option;

$some = Option::some('ana');
$none = Option::none();

// The most common entry point: convert a nullable into an Option
$name = Option::fromNullable($payload['name'] ?? null);

Transforming values

$name = Option::fromNullable($payload['name'] ?? null)
    ->map('trim')
    ->flatMap(fn (string $value): Option =>
        $value === '' ? Option::none() : Option::some($value)
    )
    ->unwrapOr('guest');

• map(fn) transforms the inner value. If the callback returns null, the result collapses to None (same semantics as fromNullable).
• flatMap(fn) chains an operation that itself returns an Option.
• filter(predicate) keeps the value only if the predicate holds.

$adult = Option::some($age)->filter(fn (int $a): bool => $a >= 18);

Extracting values

$option->unwrap();                       // value, or throws UnwrapNoneException on None
$option->unwrapOr('default');            // value or eager fallback
$option->unwrapOrElse(fn () => costly());// value or lazy fallback
$option->expect('name is required');     // value, or throws with your message

Prefer match when both branches need handling:

$greeting = $option->match(
    fn (string $name): string => "Hello, {$name}",
    fn (): string => 'Hello, guest'
);

Converting to Result

When absence should become a typed error, convert to a Result:

$result = Option::fromNullable($user)->okOr('user_not_found');
$result = Option::fromNullable($user)->okOrElse(fn () => makeError());

API summary

Method	Description
Option::some($v) / Option::none() / Option::fromNullable($v)	Constructors
map(fn) / flatMap(fn) / filter(fn)	Transformations
match(onSome, onNone)	Exhaustive handling
unwrap() / unwrapOr($d) / unwrapOrElse(fn) / expect($msg)	Extraction
okOr($err) / okOrElse(fn)	Convert to Result
isSome() / isNone()	Inspection