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fix `foldl' error messages and avoid redundant checking

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Closes PR 11066
This commit is contained in:
Matthew Flatt 2011-04-14 08:48:22 -06:00
parent e747937ceb
commit 342186b034
1 changed files with 9 additions and 13 deletions
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22
collects/racket/private/list.rkt
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@ -158,7 +158,7 @@
(apply raise-type-error name "list" 2 proc init l more))
(if (null? more)
(unless (procedure-arity-includes? proc 2)
(raise-mismatch-error name "arity mismatch, does not accept 1 argument: " proc))
(raise-mismatch-error name "given procedure does not accept 2 arguments: " proc))
(let ([len (length l)])
(let loop ([more more][n 3])
(unless (null? more)
@ -171,8 +171,8 @@
(loop (cdr more) (add1 n))))
(unless (procedure-arity-includes? proc (+ 2 (length more)))
(raise-mismatch-error name
(format "arity mismatch, does not accept ~a arguments: "
(add1 (length more)))
(format "given procedure does not accept ~a arguments: "
(+ 2 (length more)))
proc)))))
(define foldl
@ -184,11 +184,9 @@
[(f init l . ls)
(check-fold 'foldl f init l ls)
(let loop ([init init] [ls (cons l ls)])
(cond [(andmap pair? ls)
(loop (apply f (mapadd car ls init)) (map cdr ls))]
[(ormap pair? ls)
(error 'foldl "received non-equal length input lists")]
[else init]))]))
(if (pair? (car ls)) ; `check-fold' ensures all lists have equal length
(loop (apply f (mapadd car ls init)) (map cdr ls))
init))]))
(define foldr
(case-lambda
@ -201,11 +199,9 @@
[(f init l . ls)
(check-fold 'foldr f init l ls)
(let loop ([ls (cons l ls)])
(cond [(andmap pair? ls)
(apply f (mapadd car ls (loop (map cdr ls))))]
[(ormap pair? ls)
(error 'foldr "received non-equal length input lists")]
[else init]))]))
(if (pair? (car ls)) ; `check-fold' ensures all lists have equal length
(apply f (mapadd car ls (loop (map cdr ls))))
init))]))
(define (filter f list)
(unless (and (procedure? f)