Div PHP Laze
laze is a PHP library designed for defining lazy evaluation. Values are set as closures and only materialize upon first access, ensuring efficient and controlled initialization. Once a closure function is evaluated, it becomes immutable and cannot be redefined as a different value. However, it can be redefined as a closure until it’s accessed, at which point it transforms into a non-closure value.
laze might be an English word that suggests relaxation or laziness, but in this context, it’s actually an acronym derived from Lazy Evaluation. This refers to a programming technique where the evaluation of an expression is delayed until its value is needed. With laze, once the value is evaluated, it becomes an immutable value. In other words, a value that, although evaluated with delay, cannot be modified after its initial evaluation. Thus, laze encapsulates the concept of deferred evaluation that results in a definitive value, combining flexibility and robustness into one concept.
To define a lazy constant, use the laze::define method. The value must be provided as a closure.
use divengine\laze;
// Define a lazy constant
laze::define('MY_CONSTANT', fn() => computeExpensiveValue());
To access the value, use the Laze::read method. The closure will be evaluated on the first access, and the result will be stored as the constant's value.
$value = laze::read('MY_CONSTANT');
use divengine\laze;
// Define a lazy constant. Simulate an expensive computation
laze::define('MY_CONSTANT', fn() => return rand(1, 100));
// First access, the closure is evaluated
$value = laze::read('MY_CONSTANT');
echo $value; // Outputs the evaluated value
// Subsequent access returns the stored value
$value = laze::read('MY_CONSTANT');
echo $value; // Outputs the same value as before
laze with PHPUnitlaze can be particularly useful in testing environments where you need to redefine values differently from their production values. This example demonstrates how to define a lazy value in a standard PHP file and then override it during unit tests.
index.phpIn your index.php file, define a lazy constant using laze::define and create a function that uses this constant.
use divengine\laze;
require_once 'vendor/autoload.php';
// Define a lazy constant
laze::define('GREETING', fn() => 'Hello, World!');
// Function that uses the lazy constant
function getGreeting()
{
return laze::read('GREETING');
}
Create a bootstrap.php file in your tests directory. This file will be loaded before any tests are executed, allowing you to redefine the constant GREETING for testing purposes.
use divengine\laze;
require_once __DIR__ . '/../index.php';
// Redefine the constant `GREETING` only in the test context
laze::define('GREETING', fn() => 'Hello, PHPUnit!');
In your tests/LazeTest.php, write tests to ensure that the constant behaves as expected both in normal and test contexts.
use PHPUnit\Framework\TestCase;
class LazeTest extends TestCase
{
public function testGreeting()
{
// Verify that the function getGreeting returns the redefined constant
$this->assertEquals('Hello, PHPUnit!', getGreeting());
}
public function testOriginalGreeting()
{
// Check behavior without the PHPUnit bootstrap context
// Run this without the PHPUnit bootstrap to see the difference
$this->assertEquals('Hello, World!', getGreeting());
}
}
Ensure that your phpunit.xml is configured to include the bootstrap file:
<phpunit bootstrap="tests/bootstrap.php">
<testsuites>
<testsuite name="Laze Test Suite">
<directory>./tests</directory>
</testsuite>
</testsuites>
</phpunit>
You can run the tests using the following command:
phpunit
In the test environment, getGreeting() will return Hello, PHPUnit!, as the constant GREETING has been redefined.
In a normal (non-test) environment, getGreeting() will return Hello, World!, using the original definition.
This approach allows you to test your application with different constant values without affecting the production code, providing a powerful way to manage test scenarios with laze.
This project is licensed under the GNU GENERAL PUBLIC LICENSE. See the LICENSE file for details.
Contributions are welcome! Please feel free to submit a Pull Request or open an Issue.
laze is developed and maintained by Divengine Software Solutions. If you find this library useful, please consider starring the repository and sharing it with others.