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-rw-r--r--guix/utils.scm24
-rw-r--r--tests/utils.scm8
2 files changed, 32 insertions, 0 deletions
diff --git a/guix/utils.scm b/guix/utils.scm
index 1f3c0c8ad6..b730340eda 100644
--- a/guix/utils.scm
+++ b/guix/utils.scm
@@ -1,5 +1,6 @@
;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2012, 2013 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2013 Mark H Weaver <mhw@netris.org>
;;;
;;; This file is part of GNU Guix.
;;;
@@ -62,6 +63,7 @@
guile-version>?
package-name->name+version
string-tokenize*
+ string-replace-substring
file-extension
file-sans-extension
call-with-temporary-output-file
@@ -387,6 +389,28 @@ like `string-tokenize', but SEPARATOR is a string."
(else
(reverse (cons string result))))))
+(define* (string-replace-substring str substr replacement
+ #:optional
+ (start 0)
+ (end (string-length str)))
+ "Replace all occurrences of SUBSTR in the START--END range of STR by
+REPLACEMENT."
+ (match (string-length substr)
+ (0
+ (error "string-replace-substring: empty substring"))
+ (substr-length
+ (let loop ((start start)
+ (pieces (list (substring str 0 start))))
+ (match (string-contains str substr start end)
+ (#f
+ (string-concatenate-reverse
+ (cons (substring str start) pieces)))
+ (index
+ (loop (+ index substr-length)
+ (cons* replacement
+ (substring str start index)
+ pieces))))))))
+
(define (call-with-temporary-output-file proc)
"Call PROC with a name of a temporary file and open output port to that
file; close the file and delete it when leaving the dynamic extent of this
diff --git a/tests/utils.scm b/tests/utils.scm
index 4f6ecc514d..017d9170fa 100644
--- a/tests/utils.scm
+++ b/tests/utils.scm
@@ -82,6 +82,14 @@
(string-tokenize* "foo!bar!" "!")
(string-tokenize* "foo+-+bar+-+baz" "+-+")))
+(test-equal "string-replace-substring"
+ '("foo BAR! baz"
+ "/gnu/store/chbouib"
+ "")
+ (list (string-replace-substring "foo bar baz" "bar" "BAR!")
+ (string-replace-substring "/nix/store/chbouib" "/nix/" "/gnu/")
+ (string-replace-substring "" "foo" "bar")))
+
(test-equal "fold2, 1 list"
(list (reverse (iota 5))
(map - (reverse (iota 5))))