(How to Write a (Lisp) Interpreter (In Python))
norvig.com
norvig.com
Treat x as callable and call it with a symbol representing a member method:
(x 'val)
Or have a macro that takes the object and method name as arguments, for example: (send x val)
I've also seen schemes that have class definitions introduce functions for each method/property so if x is an instance of SomeClass: (SomeClass-val x)