PHP code example of catpaw / unsafe

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

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

    

catpaw / unsafe example snippets

try {
    // some code
} catch(SomeException1 $e){
    // manage error 1
} catch(SomeException2 $e) {
    // manage error 2
} catch(SomeException3 $e) {
    // manage error 3
}

try {
    // some code
} catch(SomeException1|SomeException2|SomeException3 $e){
    // manage all errors in one place
}

namespace CatPaw\Unsafe;
/**
 * @template T
 */
readonly class Unsafe {
    /** @var T $value */
    public $value;
    public false|Error $error;
}

namespace CatPaw\Unsafe;
/**
 * @template T
 * @param T $value
 * @return Unsafe<T>
 */
function ok($value);

namespace CatPaw\Core;
/**
 * @param string|Error $error
 * @return Unsafe<void>
 */
function error($error);

use CatPaw\Unsafe\Unsafe;
use function CatPaw\Unsafe\anyError;
use function CatPaw\Unsafe\error;
use function CatPaw\Unsafe\ok;

// This is not     public function __toString() {
        return "I'm looking for $this->fileName, where's the file Lebowski????";
    }
}

/**
 * Attempt to open a file.
 * @param string $fileName 
 * @return Unsafe<resource> 
 */
function openFile(string $fileName){
    if(!file_exists($fileName)){
        return error(new FileNotFoundError($fileName));
    }
    if(!$file = fopen('file.txt', 'r+')){
        return error("Something went wrong while trying to open file $fileName.");
    }
    return ok($file);
}

/**
 * Attempt to read 5 bytes from the file.
 * @param resource $stream 
 * @return Unsafe<string> 
 */
function readFile($stream){
    $content = fread($stream, 5);
    if(false === $content){
        return error("Couldn't read from stream.");
    }

    return ok($content);
}

/**
 * Attempt to close the file.
 * @param resource $stream 
 * @return Unsafe<void> 
 */
function closeFile($stream){
    if(!fclose($stream)){
        return error("Couldn't close file.");
    }
    return ok();
}

// open file
$file = openFile('file.txt')->try($error);
if ($error) {
    echo $error.PHP_EOL;
    die();
}

// read contents
$contents = readFile($file)->try($error);
if ($error) {
    echo $error.PHP_EOL;
    die();
}

// close file
closeFile($file)->try($error);
if ($error) {
    echo $error.PHP_EOL;
    die();
}

echo $contents.PHP_EOL;

if($error){
    echo $error.PHP_EOL;
    // manage error here...
}

$contents = anyError(function() {
    // open file
    $file = openFile('file.txt')->try($error)
    or yield $error;

    // read contents
    $contents = readFile($file)->try($error)
    or yield $error;


    // close file
    closeFile($file)->try($error)
    or yield $error;

    return $contents;
})->try($error);

if($error){
    echo $error.PHP_EOL;
    die();
}

echo $contents.PHP_EOL;

if($error){
    return error($error);
}

$result = anyError(/* ... */)->try($error) or match($error:class){
    FileNotFoundError::class => $error->getMessage(),
    default => "Let me explain something to you. Um, I am not Mr. Lebowski. You're Mr. Lebowski.",

};