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authorLudovic Courtès <ludo@gnu.org>2013-07-10 18:04:08 +0200
committerLudovic Courtès <ludo@gnu.org>2013-07-10 21:52:51 +0200
commitc8772a7a21f954b5e75746529e70edc3a1017249 (patch)
tree03792f0a3dd41d5af5d4bf833bf6bfcebb992ae8
parentb7b88288011aa41791b6634ae229f426bacc55ce (diff)
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.
-rw-r--r--guix/records.scm16
-rw-r--r--tests/records.scm6
2 files changed, 19 insertions, 3 deletions
diff --git a/guix/records.scm b/guix/records.scm
index 57664df5a6..8dc733b8ff 100644
--- a/guix/records.scm
+++ b/guix/records.scm
@@ -198,9 +198,19 @@ thunked fields."
#'((field options ...)
...))))))))))
-(define (alist->record alist make keys)
- "Apply MAKE to the values associated with KEYS in ALIST."
- (let ((args (map (cut assoc-ref alist <>) keys)))
+(define* (alist->record alist make keys
+ #:optional (multiple-value-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)))
(define (object->fields object fields port)
diff --git a/tests/records.scm b/tests/records.scm
index d0635ebb1f..712eb83a09 100644
--- a/tests/records.scm
+++ b/tests/records.scm
@@ -158,6 +158,12 @@ Version: 1.5
(list (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)