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Fix R6RS `fold-left' so the accumulator is the first argument.

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* module/rnrs/lists.scm (fold-left): New procedure.

* module/rnrs/records/syntactic.scm (define-record-type): Fix to use
  corrected `fold-left'.

* test-suite/tests/r6rs-lists.test: Add tests.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>
This commit is contained in:
Ian Price 2011-10-26 20:24:05 +01:00 • committed by Ludovic Courtès
parent 2be3feb17e
commit d825841db0
3 changed files with 37 additions and 5 deletions
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12
module/rnrs/lists.scm
View file

@ -22,8 +22,7 @@
remv remq memp member memv memq assp assoc assv assq cons*)
(import (rnrs base (6))
(only (guile) filter member memv memq assoc assv assq cons*)
(rename (only (srfi srfi-1) fold
any
(rename (only (srfi srfi-1) any
every
remove
member
@ -32,7 +31,6 @@
partition
fold-right
filter-map)
(fold fold-left)
(any exists)
(every for-all)
(remove remp)
@ -40,6 +38,14 @@
(member memp-internal)
(assoc assp-internal)))
(define (fold-left combine nil list . lists)
(define (fold nil lists)
(if (exists null? lists)
nil
(fold (apply combine nil (map car lists))
(map cdr lists))))
(fold nil (cons list lists)))
(define (remove obj list) (remp (lambda (elt) (equal? obj elt)) list))
(define (remv obj list) (remp (lambda (elt) (eqv? obj elt)) list))
(define (remq obj list) (remp (lambda (elt) (eq? obj elt)) list))

4
module/rnrs/records/syntactic.scm
View file

@ -134,13 +134,13 @@
(let* ((fields (if (unspecified? _fields) '() _fields))
(field-names (list->vector (map car fields)))
(field-accessors
(fold-left (lambda (x c lst)
(fold-left (lambda (lst x c)
(cons #`(define #,(cadr x)
(record-accessor record-name #,c))
lst))
'() fields (sequence (length fields))))
(field-mutators
(fold-left (lambda (x c lst)
(fold-left (lambda (lst x c)
(if (caddr x)
(cons #`(define #,(caddr x)
(record-mutator record-name

26
test-suite/tests/r6rs-lists.test
View file

@ -30,3 +30,29 @@
(let ((d '((3 a) (1 b) (4 c))))
(equal? (assp even? d) '(4 c)))))
(with-test-prefix "fold-left"
(pass-if "fold-left sum"
(equal? (fold-left + 0 '(1 2 3 4 5))
15))
(pass-if "fold-left reverse"
(equal? (fold-left (lambda (a e) (cons e a)) '() '(1 2 3 4 5))
'(5 4 3 2 1)))
(pass-if "fold-left max-length"
(equal? (fold-left (lambda (max-len s)
(max max-len (string-length s)))
0
'("longest" "long" "longer"))
7))
(pass-if "fold-left with-cons"
(equal? (fold-left cons '(q) '(a b c))
'((((q) . a) . b) . c)))
(pass-if "fold-left sum-multiple"
(equal? (fold-left + 0 '(1 2 3) '(4 5 6))
21))
(pass-if "fold-left pairlis"
(equal? (fold-left (lambda (accum e1 e2)
(cons (cons e1 e2) accum))
'((d . 4))
'(a b c)
'(1 2 3))
'((c . 3) (b . 2) (a . 1) (d . 4)))))