Method demo

examples/demo.php:1096–1126

()

class ClosureInvocationDemo
{
    public function demo(): void
    {
        // Closure literal with native return type hint
        $makePen = function(): Pen { return new Pen(); };
        $makePen()->write();                      // resolves Pen from closure return type

        // Arrow function literal
        $makePencil = fn(): Pencil => new Pencil();
        $makePencil()->sketch();                  // arrow fn return type

        // Docblock callable annotation
        /** @var \Closure(): Pencil $supplier */
        $supplier = getUnknownValue();
        $supplier()->sharpen();                   // @var Closure() annotation

        // Chaining after callable invocation
        $builder = function(): Pen { return new Pen(); };
        $builder()->rename('Bold')->write();      // chain after $fn()

        // Variable assigned from callable invocation
        $fromClosure = $makePen();
        $fromClosure->write();                    // $result = $fn() resolves return type

        // Immediately invoked arrow function with return type
        $result = (fn(): Pen => new Pen())();
        $result->write();                         // resolves Pen from arrow fn return type

        // Immediately invoked closure with return type
        $obj = (function(): Pencil { return new Pencil(); })();
        $obj->sketch();                           // resolves Pencil from closure return type
    }
}