23 lines
586 B
Racket
23 lines
586 B
Racket
#lang typed/racket
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(require "../traversal.hl.rkt"
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"ck.rkt")
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(define-fold f₁ t₁ Null String)
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;(define-fold f₂ t₂ (Pairof Null Null) String)
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;(define-fold f₃ t₃ String String)
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;(define-fold f₄ t₄ (Pairof Null String) String)
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(define f₁-string->symbol
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(f₁ string?
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(λ ([x : String] [acc : Integer])
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(values (string->symbol x) acc))))
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(check-equal?-values: (f₁-string->symbol '() 0)
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'() 0)
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(check-equal?-values: (f₁-string->symbol '() 0)
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: (Values Null Integer)
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'() 0)
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