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17 lines
611 B
Racket
17 lines
611 B
Racket
3 years ago
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#lang racket/base
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(require racket/match
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"struct.rkt")
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(provide (all-defined-out))
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(define-syntax-rule (define-guarded-parameter ID PRED STARTING-VALUE)
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(define ID
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(make-parameter STARTING-VALUE
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(λ (val)
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(unless (PRED val)
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(raise-argument-error 'ID (format "~a" (object-name PRED)) val))
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val))))
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(define-guarded-parameter current-attrs (λ (xs) (and (list? xs) (andmap attr? xs))) null)
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(define-guarded-parameter show-timing boolean? #false)
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(define-guarded-parameter current-strict-attrs boolean? #false)
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