142 lines
4.7 KiB
Racket
142 lines
4.7 KiB
Racket
#lang scheme/base
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(require scheme/class)
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;; --------------------------------------------------------------------------
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(provide check-arg check-arity check-proc check-result
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check-list-list check-color
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check-fun-res check-dependencies
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natural?
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find-non tp-exn? number->ord)
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(define (natural? w)
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(and (number? w) (integer? w) (>= w 0)))
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;; (_ -> Boolean) (listof X) -> (union X false)
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(define (find-non pred? l)
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(let ([r (filter (compose not pred?) l)])
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(if (null? r) #f (car r))))
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;(: check-fun-res (∀ (γ) (∀ (β α ...) (α ...α -> β)) (_ -γ-> boolean) _ -> γ))
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(define (check-fun-res f pred? type)
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(lambda x
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(define r (apply f x))
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(check-result (object-name f) pred? type r)
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r))
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;; check-dependencies : Symbol x Boolean x FormatString x Any* -> Void
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(define (check-dependencies pname condition fmt . args)
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(unless condition
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(tp-error pname (apply format fmt args))))
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#| Tests ------------------------------------------------------------------
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(not (find-non list? '((1 2 3) (a b c))))
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(symbol? (find-non number? '(1 2 3 a)))
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(symbol? (find-non list? '((1 2 3) a (b c))))
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|#
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(define-struct (tp-exn exn) ())
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(define (tp-error name fmt . args)
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(raise
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(make-exn:fail:contract #; make-tp-exn
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(string-append (format "~a: " name) (apply format fmt args))
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(current-continuation-marks))))
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(define (number->ord i)
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(if (= i 0)
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"zeroth"
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(case (modulo i 10)
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[(0 4 5 6 7 8 9) (format "~ath" i)]
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[(1) (format "~ast" i)]
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[(2) (format "~and" i)]
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[(3) (format "~ard" i)])))
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;; spell-out : number-or-string -> string
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(define (spell-out arg-posn)
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(cond
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[(string? arg-posn) arg-posn]
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[(number? arg-posn)
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(case arg-posn
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[(1) "first"]
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[(2) "second"]
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[(3) "third"]
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[(4) "fourth"]
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[(5) "fifth"]
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[(6) "sixth"]
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[(7) "seventh"]
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[(8) "eighth"]
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[(9) "ninth"]
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[(10) "tenth"]
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[else (number->ord arg-posn)])]))
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;; Symbol (union true String) String X -> void
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(define (check-list-list pname condition pred given)
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(when (string? condition)
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(tp-error pname (string-append condition (format "\nin ~e" given)))))
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;; Symbol (_ -> Boolean) String X X *-> X
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(define (check-result pname pred? expected given . other-given)
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(if (pred? given)
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given
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(tp-error pname "result of type <~a> expected, your function produced ~a" expected
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(if (pair? other-given)
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(car other-given)
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given))))
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;; check-color : symbol (or/c str non-negative-integer) TST -> void
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(define (check-color pname arg-pos given)
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(check-arg pname
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(or (string? given)
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(symbol? given))
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'color
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arg-pos given)
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;; this would be good to check, but it isn't possible, since this
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;; file is not allowed to rely on mred.
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;; also nice would be to allow color% objects here, but that's
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;; not possible for the same reason (but that is why
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;; the '[else color]' case is below in the cond.
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#;
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(let ([color
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(cond
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[(symbol? given)
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(send the-color-database find-color (symbol->string given))]
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[(string? given)
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(send the-color-database find-color given)]
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[else given])])
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(unless color
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(tp-error pname
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"expected the name ~e to be a color, but did not recognize it"
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given))))
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;; check-arg : sym bool str (or/c str non-negative-integer) TST -> void
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(define (check-arg pname condition expected arg-posn given)
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(unless condition
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(tp-error pname "expected <~a> as ~a argument, given: ~e"
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expected
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(spell-out arg-posn)
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given)))
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;; check-arity : sym num (list-of TST) -> void
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(define (check-arity name arg# args)
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(if (= (length args) arg#)
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(void)
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(tp-error name "expects ~a arguments, given ~e" arg# (length args))))
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;; check-proc :
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;; sym (... *->* ...) num (union sym str) (union sym str) -> void
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(define (check-proc proc f exp-arity arg# arg-err)
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(unless (procedure? f)
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(tp-error proc "procedure expected as ~a argument; given ~e" arg# f))
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(let ([arity-of-f (procedure-arity f)])
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(unless (procedure-arity-includes? f exp-arity) ; (and (number? arity-of-f) (>= arity-of-f exp-arity))
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(tp-error proc "procedure of ~a expected as ~a argument; given procedure of ~a "
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arg-err arg#
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(cond
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[(number? arity-of-f)
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(if (= arity-of-f 1)
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(format "1 argument")
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(format "~s arguments" arity-of-f))]
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[(arity-at-least? arity-of-f) "variable number of arguments"]
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[else (format "multiple arities (~s)" arity-of-f)])))))
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