README

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 provides lazy immutable values for PHP. You define a key with a closure, and the value is computed on first read and then cached.

Requirements

• PHP 8.0 or higher

Installation

composer require divengine/laze

Quick start

<?php

require 'vendor/autoload.php';

use divengine\laze;

laze::define('APP_NAME', fn () => 'Laze Demo');

echo laze::read('APP_NAME');

Core API

• laze::define($key, $callable) registers a lazy value.
• laze::read($key) evaluates once and returns the stored value.
• laze::defined($key) checks if a key exists.
• laze::evaluated($key) checks if a key was evaluated (throws if undefined).
• laze::constraint($name, $checker) validates values on evaluation.

Redefinition rules

You can redefine a value before it is evaluated. After the first read, the value becomes immutable and further define calls are ignored.

<?php

laze::define('FOO', fn () => 1);
laze::define('FOO', fn () => 2);

echo laze::read('FOO'); // 2

laze::define('FOO', fn () => 3);
echo laze::read('FOO'); // still 2

Constraints

<?php

laze::constraint(
    'APP_PORT must be an int',
    fn ($key, $value) => $key === 'APP_PORT' ? is_int($value) : true
);

laze::define('APP_PORT', fn () => 8080);

Constraints run when a value is evaluated. If a constraint returns false, read throws an exception.

Testing tips

Laze stores state statically. You can reset it between tests with reflection:

<?php

use divengine\laze;

$reflection = new ReflectionClass(laze::class);

$store = $reflection->getProperty('store');
$store->setAccessible(true);
$store->setValue(null, []);

$constraints = $reflection->getProperty('constraints');
$constraints->setAccessible(true);
$constraints->setValue(null, []);

$evaluated = $reflection->getProperty('evaluated');
$evaluated->setAccessible(true);
$evaluated->setValue(null, []);

Or run PHPUnit with process isolation:

vendor/bin/phpunit --process-isolation

Docs

See docs/README.md for guides and FAQ.

License

This project is licensed under the GNU General Public License. See LICENSE.

Contributing

Contributions are welcome. Please open an issue or submit a pull request.

About

Laze is developed and maintained by Divengine Software Solutions.