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54 lines
1.4 KiB
Racket
54 lines
1.4 KiB
Racket
#lang br/quicklang
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(define-macro (bf-module-begin PARSE-TREE)
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#'(#%module-begin
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PARSE-TREE))
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(provide (rename-out [bf-module-begin #%module-begin]))
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(define-macro (bf-program OP-OR-LOOP ...)
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#'(define-values (vec ptr)
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(run-args (list OP-OR-LOOP ...))))
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(provide bf-program)
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(define (run-args bf-funcs
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[vec-start (make-vector 30000 0)]
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[pos-start 0])
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(for/fold ([vec vec-start]
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[pos pos-start])
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([bf-func (in-list bf-funcs)])
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(bf-func vec pos)))
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(define (vector-set v p val)
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(vector-set! v p val)
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v)
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(define (vector-update v p func)
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(vector-set v p (func (vector-ref v p))))
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(define (gt v p) (values v (add1 p)))
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(define (lt v p) (values v (sub1 p)))
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(define (plus v p) (values (vector-update v p add1) p))
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(define (minus v p) (values (vector-update v p sub1) p))
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(define (period v p) (write-byte (vector-ref v p)) (values v p))
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(define (comma v p) (values (vector-set v p (read-byte)) p))
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(define-macro-cases op
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[(op ">") #'gt]
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[(op "<") #'lt]
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[(op "+") #'plus]
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[(op "-") #'minus]
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[(op ".") #'period]
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[(op ",") #'comma])
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(provide op)
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(define (make-looping-func args)
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(lambda (v p)
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(for/fold ([vec v]
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[pos p])
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([i (in-naturals)]
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#:break (zero? (vector-ref vec pos)))
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(run-args args vec pos))))
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(define-macro (loop LOOP-ARG ...)
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#'(make-looping-func (list LOOP-ARG ...)))
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(provide loop) |