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18 lines
473 B
Racket
18 lines
473 B
Racket
10 years ago
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#lang typed/racket/base
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(provide (all-defined-out))
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;; Typed versions of common library functions, to avoid require/typed
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(: empty? (Any . -> . Boolean : Null))
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(define (empty? l)
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(null? l))
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(: empty Null)
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(define empty '())
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#;(: flatten (Any . -> . (Listof Any)))
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#;(define (flatten orig-sexp)
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(let loop ([sexp orig-sexp] [acc null])
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(cond [(null? sexp) acc]
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[(pair? sexp) (loop (car sexp) (loop (cdr sexp) acc))]
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[else (cons sexp acc)])))
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