funstacker.rkt

#lang br/quicklang

(define (read-syntax path port)
  (define args (port->lines port))
  (define handle-datums (format-datums '~a args))
  (define module-datum `(module funstacker-mod "funstacker.rkt"
                          (handle-args ,@handle-datums)))
  (datum->syntax #f module-datum))
(provide read-syntax)

(define-macro (funstacker-module-begin HANDLE-ARGS-EXPR)
  #'(#%module-begin
     (display (first HANDLE-ARGS-EXPR))))
(provide (rename-out [funstacker-module-begin #%module-begin]))

(define (handle-args . args)
  (for/fold ([stack-acc empty]) ; accumulator
            ([arg (filter-not void? args)]) ; iterator
    (cond
      [(number? arg) (cons arg stack-acc)]
      [(or (equal? + arg) (equal? * arg))
       (let ([op-result (arg (first stack-acc) (second stack-acc))])
         (cons op-result (drop stack-acc 2)))]
      )))

(provide handle-args)

(provide + *)