php7-optional

Installation

composer require ifixit/php7-optional

Usage

There are 3 main classes:

• Optional\Option
  • Conceptually: Some or None. This is a box that optionally holds a value. Use this to replace null.
• Optional\Either
  • Conceptually: Left or Right. This is a box that is bi-state. Can be Left, or Right. Not Both, not none. You can apply the same transformations to the left side as you can to the right.
• Optional\Result
  • Conceptually: Okay or Error. This is a box that is bi-state, but leans towards okay state. The error state is limited as we want to make this object easy to deal with mapping or dump error.
  • All callables have Throwable auto wrapped and thrown at the end of the chain.
• Optional\UnsafeResult
  • Conceptually: Okay or Error. This is a box that is bi-state, but leans towards okay state. The error state is limited as we want to make this object easy to deal with mapping or dump error.
  • All callables do not have Throwable auto wrapped. Thus, an Exception will be thrown immediately.

Read the full docs

Using Option

To use Optional, simply import the following namespace:

use Optional\Option;

Creating optional values

There are examples under examples.

Here is one of them which will show how fluently you can describe the chnage you want to apply.

use Optional\Result;

class Curl {
   public static function request(string $url): array {
      return [
         'code' => 200,
         'url' => $url,
         'data' =>
            '{
               "environment_config": {
                 "app": {
                   "name": "Sample App",
                   "url": "http://10.0.0.120:8080/app/"
                 },
                 "database": {
                   "name": "mysql database",
                   "host": "10.0.0.120",
                   "port": 3128,
                   "username": "root",
                   "password": "toor"
                 },
                 "rest_api": "http://10.0.0.120:8080/v2/api/"
               }
             }'
      ];
   }
}

$responseToResult = function (array $response): Result {
   $wasGood = $response['code'] == 200;

   if ($wasGood) {
      return SimpleResult::okay($response);
   } else {
      $url = $response['url'];
      $code = $response['code'];
      return SimpleResult::error("The request to $url failed with code $code!");
   }
};

$response = Curl::request('http:://www.github.com');

$result = $responseToResult($response);

$dbConnectionStr = $result
   ->map(function ($result) {
      return json_decode($result['data'], true);
   })
   ->notFalsy("Json failed to decode!")
   ->map(function(array $json) {
      $dbData = $json['environment_config']['database'];

      $host = $dbData['host'];
      $port = $dbData['port'];
      $username = $dbData['username'];
      $password = $dbData['password'];

      return "Server=$host;Port=$port;Uid=$username;Pwd=$password;";
   })
   ->dataOrThrow();

echo "Connection str: $dbConnectionStr \n";


$dbConnectionResult = $result
   ->map(function ($result) {
      return false;
   })
   ->notFalsy("Json failed to decode!")
   ->map(function(array $json) {
      $dbData = $json['environment_config']['database'];

      $host = $dbData['host'];
      $port = $dbData['port'];
      $username = $dbData['username'];
      $password = $dbData['password'];

      return "Server=$host;Port=$port;Uid=$username;Pwd=$password;";
   });

   try {
      $dbConnectionResult->dataOrThrow();
   } catch (Throwable $ex) {
      // Don't want to kill the example
      echo "Example of a wrapped exception: {$ex->getMessage()}\n";
   }

   $defaultValue = $dbConnectionResult
   ->orSetDataTo('Server=myServerAddress;Port=1234;Database=myDataBase;Uid=myUsername;Pwd=myPassword;')
   ->dataOrThrow();

   echo "Example of setting to a default: $defaultValue\n";

Using Either

To use Either, simply import the following namespace:

use Optional\Either;

Using Result

To use Result, simply import the following namespace:

use Optional\Result;

Result Methods

Creation (Boxing)

---

• static okay($data): Result
• static error(Throwable $errorData): Result
• static okayWhen($data, Throwable $errorValue, callable $filterFunc): Result
• static errorWhen($data, Throwable $errorValue, callable $filterFunc): Result
• static okayNotNull($data, Throwable $errorValue): Result
• static fromArray(array $array, $key, Throwable $rightValue = null): Result

Flipping

---

• toError($errorValue): Result
• toOkay($dataValue): Result

Unboxing

---

• dataOrThrow()

State

---

• isOkay(): bool
• isError(): bool
• contains($value): bool
• errorContains($value): bool
• exists(callable $existsFunc): bool

Transformation

---

• orSetDataTo($data): Result
• orCreateResultWithData(callable $alternativeFactory): Result
• okayOr(self $alternativeResult): Result
• createIfError(callable $alternativeResultFactory): Result
• map(callable $mapFunc): Result
• mapError(callable $mapFunc): Result
• andThen(callable $mapFunc): Result
• flatMap(callable $mapFunc): Result
• toErrorIf(callable $filterFunc, Throwable $errorValue): Result
• toOkayIf(callable $filterFunc, $data): Result
• notNull(Throwable $errorValue): Result
• notFalsy(Throwable $errorValue): Result

Side Effect

• run(callable $dataFunc, callable $errorFunc)
• runOnOkay(callable $dataFunc): void
• runOnError(callable $errorFunc): void

Licence

MIT

Special Thanks

Heavily inspired by https://github.com/nlkl/Optional. In fact this is essentially a port of this library.