functional stacker

This commit is contained in:
Peter Hart 2020-02-21 18:33:03 -05:00
parent 0e7f17311c
commit 5027febcfc
6 changed files with 78 additions and 1 deletions

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#lang reader "funstacker.rkt"
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*

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#lang reader "stacker.rkt"
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*

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funstacker/funstacker.rkt Normal file
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#lang br/quicklang
(define (read-syntax path port)
(define src-lines (port->lines port))
(define src-datums (format-datums '~a src-lines))
(define module-datum `(module stacker-mod "funstacker.rkt"
(handle-args ,@src-datums)))
(datum->syntax #f module-datum))
(provide read-syntax)
(define-macro (stacker-module-begin HANDLE-ARGS-EXPR)
#'(#%module-begin
(display (first HANDLE-ARGS-EXPR))))
(provide (rename-out [stacker-module-begin #%module-begin]))
(define (handle-args . args)
(for/fold ([stack-acc empty])
([arg (in-list args)]
#:unless (void? arg))
(cond
[(number? arg) (cons arg stack-acc)]
[(or (equal? * arg) (equal? + arg))
(define op-result
(arg (first stack-acc) (second stack-acc)))
(cons op-result (drop stack-acc 2))])))
(provide handle-args)
(provide + *)

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#lang br/quicklang
(define (read-syntax path port)
(define src-lines (port->lines port))
(define src-datums (format-datums '(handle ~a) src-lines))
(define module-datum `(module stacker-mod "stacker.rkt"
,@src-datums))
(datum->syntax #f module-datum))
(provide read-syntax)
(define-macro (stacker-module-begin HANDLE-EXPR ...)
#'(#%module-begin
HANDLE-EXPR ...
(display (first stack))))
(provide (rename-out [stacker-module-begin #%module-begin]))
(define stack empty)
(define (pop-stack!)
(define arg (first stack))
(set! stack (rest stack))
arg)
(define (push-stack! arg)
(set! stack (cons arg stack)))
(define (handle [arg #f])
(cond
[(number? arg) (push-stack! arg)]
[(or (equal? + arg) (equal? * arg))
(define op-result (arg (pop-stack!) (pop-stack!)))
(push-stack! op-result)]))
(provide handle)
(provide + *)

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("7.5" racket ("7f677926d966a8cec92cb8a8b1e1bd44f09f4aab" . "f00a81ce44a6ee4c31b492d8e2e91c13a4a1e5aa") (collects #"br" #"quicklang.rkt") (collects #"errortrace" #"errortrace-key.rkt") (collects #"racket" #"runtime-config.rkt"))