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records: `alist->record' supports multiple-field occurrences. 

* guix/records.scm (alist->record): Add `multiple-value-keys'
  parameter.  Update docstring, and honor it.
* tests/records.scm ("alist->record"): New record.
This commit is contained in:
Ludovic Courtès 2013-07-10 18:04:08 +02:00
parent b7b8828801
commit c8772a7a21
2 changed files with 19 additions and 3 deletions
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16
guix/records.scm
View File

@ -198,9 +198,19 @@ thunked fields."
#'((field options ...) #'((field options ...)
...)))))))))) ...))))))))))
(define (alist->record alist make keys) (define* (alist->record alist make keys
"Apply MAKE to the values associated with KEYS in ALIST." #:optional (multiple-value-keys '()))
(let ((args (map (cut assoc-ref alist <>) keys))) "Apply MAKE to the values associated with KEYS in ALIST. Items in KEYS that
are also in MULTIPLE-VALUE-KEYS are considered to occur possibly multiple
times in ALIST, and thus their value is a list."
(let ((args (map (lambda (key)
(if (member key multiple-value-keys)
(filter-map (match-lambda
((k . v)
(and (equal? k key) v)))
alist)
(assoc-ref alist key)))
keys)))
(apply make args))) (apply make args)))
(define (object->fields object fields port) (define (object->fields object fields port)

6
tests/records.scm
View File

@ -158,6 +158,12 @@ Version: 1.5
(list (recutils->alist p) (list (recutils->alist p)
(recutils->alist p)))) (recutils->alist p))))
(test-equal "alist->record" '((1 2) b c)
(alist->record '(("a" . 1) ("b" . b) ("c" . c) ("a" . 2))
list
'("a" "b" "c")
'("a")))
(test-end) (test-end)