suzanne.soy/beautiful-racket
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update stacker source

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This commit is contained in:
Matthew Butterick 2016-07-28 10:04:04 -07:00
parent 7d5a6d45a5
commit 68922b0cb5
1 changed files with 6 additions and 5 deletions
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11
beautiful-racket/br/demo/stacker.rkt
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@ -8,10 +8,10 @@
(datum->syntax #f module-datum))
(provide read-syntax)
(define-macro (stacker-module-begin DATUM-STX ...)
(define-macro (stacker-module-begin HANDLE-EXPR ...)
#'(#%module-begin
DATUM-STX ...
(display (pop-stack!))))
HANDLE-EXPR ...
(display (first stack))))
(provide (rename-out [stacker-module-begin #%module-begin]))
(define stack empty)
@ -27,11 +27,12 @@
(define (handle [arg #f])
(cond
[(number? arg) (push-stack! arg)]
[(procedure? arg)
[(or (equal? * arg) (equal? + arg))
(define op-result (arg (pop-stack!) (pop-stack!)))
(push-stack! op-result)]))
(provide handle)
(provide handle + *)
(provide + *)
(module+ test
(require rackunit)