public function if($name, callable $callback)
    {
        $this->conditions[$name] = $callback;

        $this->directive($name, function ($expression) use ($name) {
            return $expression !== ''
                    ? "<?php if (\Illuminate\Support\Facades\Blade::check('{$name}', {$expression})): ?>"
                    : "<?php if (\Illuminate\Support\Facades\Blade::check('{$name}')): ?>";
        });

        $this->directive('else'.$name, function ($expression) use ($name) {
            return $expression !== ''
                ? "<?php elseif (\Illuminate\Support\Facades\Blade::check('{$name}', {$expression})): ?>"
                : "<?php elseif (\Illuminate\Support\Facades\Blade::check('{$name}')): ?>";
        });

        $this->directive('end'.$name, function () {
            return '<?php endif; ?>';
        });
    }