scopes

Scope.php

<?php

namespace Fesor\Caffeine;

final class Scope
{
    private $payload;

    private $parent;

    /**
     * Scope constructor.
     * @param Scope $parent
     */
    private function __construct(Scope $parent = null)
    {
        $this->parent = $parent;
        $this->payload = [];
    }

    public static function create()
    {
        return new self();
    }

    public static function withPayload(array $payload)
    {
        $scope = new self();
        $scope->payload = $payload;

        return $scope;
    }

    public function __get($name)
    {
        $scope = $this;
        while($scope) {
            if (array_key_exists($name, $scope->payload)) {
                return $scope->payload[$name];
            }

            $scope = $scope->parent;
        }

        return null;
    }

    public function __set($name, $value)
    {
        $this->payload[$name] = $value;
    }

    function __isset($name)
    {
        $scope = $this;
        while($scope) {
            if (array_key_exists($name, $scope->payload)) {
                return true;
            }

            $scope = $scope->parent;
        }

        return false;
    }
    
    public function __call($name, $arguments)
    {
        $callable = $this->__get($name);
        if (is_callable($callable)) {
            return call_user_func_array($callable, $arguments);
        }

        throw new \BadMethodCallException(sprintf('Method "%s" not found in current scope neither it parents'));
    }

    public function inherit()
    {
        return new self($this);
    }

    public function bind(\Closure $callable)
    {
        \Closure::bind($callable, $this, $this);
    }
}

usage.php

<?php

$rootScope = new Scope();
$rootScope->val = 'default';

$scope1 = $rootScope->inherit();
$scope1->val = 'scope 1 val';

$childScope = $scope1->inherit();
$childScope->val = 'child scope val'

$scope2 = $rootScope->inherit();
$scope2->val = 'scope 2 val';