From 5e1103821a566e55c848c8fa323d07801cce6ab7 Mon Sep 17 00:00:00 2001
From: Ludovic Courtès <ludo@gnu.org>
Date: Wed, 1 Oct 2014 10:19:14 +0200
Subject: utils: Add 'strip-keyword-arguments'.

* guix/utils.scm (strip-keyword-arguments): New procedure.
* tests/utils.scm ("strip-keyword-arguments"): New test.
---
 guix/utils.scm | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

(limited to 'guix/utils.scm')

diff --git a/guix/utils.scm b/guix/utils.scm
index 34a5e6c971..2814247a68 100644
--- a/guix/utils.scm
+++ b/guix/utils.scm
@@ -48,6 +48,7 @@ (define-module (guix utils)
             compile-time-value
             fcntl-flock
             memoize
+            strip-keyword-arguments
             default-keyword-arguments
             substitute-keyword-arguments
 
@@ -424,6 +425,21 @@ (define (memoize proc)
               (hash-set! cache args results)
               (apply values results)))))))
 
+(define (strip-keyword-arguments keywords args)
+  "Remove all of the keyword arguments listed in KEYWORDS from ARGS."
+  (let loop ((args   args)
+             (result '()))
+    (match args
+      (()
+       (reverse result))
+      (((? keyword? kw) arg . rest)
+       (loop rest
+             (if (memq kw keywords)
+                 result
+                 (cons* arg kw result))))
+      ((head . tail)
+       (loop tail (cons head result))))))
+
 (define (default-keyword-arguments args defaults)
   "Return ARGS augmented with any keyword/value from DEFAULTS for
 keywords not already present in ARGS."
-- 
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