(define *dstack* '())
(define *funcs* (make-hash-table 'eqv?))

(define-syntax define-command
  (syntax-rules ()
    [(_ name args body ...)
     (hash-table-put! *funcs* (quote name)
                      (lambda args body ...))]))

(define-command add () (let* ((x (pop! *dstack*))
                              (y (pop! *dstack*)))
                         (rlet1 ans (+ x y)
                           (push! *dstack* ans))))

(define-command pop () (pop! *dstack*))
(define-command push (x) (push! *dstack* x) x)
(define-command dprint () (print *dstack*))
(define-command print () (print (car *dstack*)))
(define-command clean () (set! *dstack* (list)))

(define (seval cmd . args)
  (and-let* ((cont (hash-table-get *funcs* cmd #f)))
    (apply cont args)))

(let1 exprs '((push 2) (push 3) (add) (print) (pop))
  (dolist (line exprs)
    (apply seval line)))