README

A PHP implementation of Rust's Result type with roughly the same API.

Version information

Version 4.x.x requires PHP 8.1.0+. Make sure you match the versions for this and the Option library if you use both.

Installation

composer require prewk/result

Overview

use Prewk\Result;
use Prewk\Result\{Ok, Err};

function someApiCall(): Result {
    // ...
    if ($apiCallSuccesful) {
        return new Ok($results);
    } else {
        return new Err($error);
    }
}

function anotherApiCall(): Result {
    // ...
    if ($apiCallSuccesful) {
        return new Ok($results);
    } else {
        return new Err($error);
    }
}

// Fallback to value
$value = someApiCall()->unwrapOr(null);

// Fallback to result and throw an exception if both fail
$value = someApiCall()->orElse(function($err) {
	return anotherApiCall();
})->unwrap();

// Throw custom exception on error
$value = someApiCall()->expect(new Exception("Oh noes!"));

Helpers

Optional global helper functions exist to simplify result object construction:

ok(); // new Prewk\Result\Ok(null);
ok($val); // new Prewk\Result\Ok($val);
err($e); // new Prewk\Result\Err($e);

Add the following to your composer.json:

{
  "autoload": {
    "files": ["vendor/prewk/result/helpers.php"]
  }
}

API deviations from Rust

Exceptions

If an Err containing an Exception is unwrapped, that Exception will be thrown. Otherwise a generic ResultException will be thrown.

Gotchas

Note that or and and will be evaluated immediately:

// This will call all three api calls regardless of successes/errors
$this
	->apiCall()
	->or(anotherApiCall())
	->and(thirdApiCall());

See andThen and orElse for lazy evaluation.

License

MIT & Apache 2.0