PHP code example of khalyomede / monad

    
        
<?php
require_once('vendor/autoload.php');

/* Start to develop here. Best regards https://php-download.com/ */

    

khalyomede / monad example snippets

use Khalyomede\Monad\Maybe;

function getFileContent(string $filePath): Maybe
{
  $content = file_get_contents($filePath);

  return $content === false ? Maybe::nothing() : Maybe::just($content);
}

// main
$content = getFileContent("data.txt")
  ->then(fn (string $data): string => $data)
  ->catch(fn (): string => "N/A");

echo $content;

use Khalyomede\Monad\Result;

function getUsers(): Result
{
  $pdo = new PDO("sqlite::memory:");

  $statement = $pdo->prepare("SELECT * FROM users");

  if ($statement === false) {
    $message = $pdo->errorInfo()[2];

    return Result::error($message);
  }

  $result = $statement->execute();

  if ($result === false) {
    $message = $statement->errorInfo()[2];

    return Result::error($message);
  }

  return Result::ok($statement->fetchAll());
}

// main
$users = getUsers()
  ->then(fn (array $records): array => $records)
  ->catch(function (string $error): array {
    error_log($error);

    return [];
  });

use Khalyomede\Monad\Result;

function getFileContent(string $path): Result
{
  $content = file_get_contents($path);

  return $content === false ?
    Result::error(new Exception("Cannot get content of file $path.")) :
    Result::ok($content);
}

function saveFileContent(string $path, string $content): Result
{
  $result = file_put_contents($path, $content);

  return $result === false ?
    Result::error(new Exception("Cannot write file content of file $path.")) :
    Result::ok(true);
}

// main
$result = fileGetContent("composer.json")
  ->then(fn (string $content): Result => saveFileContent("composer.json.save", $content))
  ->then(fn (): string => "composer.json backup finished.")
  ->catch(fn (Exception $exception): string => $exception->getMessage());

echo $result . PHP_EOL;

bash
khalyomede@pc > php index.php
composer.json backup finished.

bash
khalyomede@pc > php index.php
Cannot get content of file composer.json.

bash
khalyomede@pc > php index.php
Cannot write file content of file composer.json.save.