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-rw-r--r--guix/gexp.scm32
1 files changed, 32 insertions, 0 deletions
diff --git a/guix/gexp.scm b/guix/gexp.scm
index 2622c5cb62..9835599bb8 100644
--- a/guix/gexp.scm
+++ b/guix/gexp.scm
@@ -78,6 +78,7 @@
gexp->script
text-file*
mixed-text-file
+ file-union
imported-files
imported-modules
compiled-modules
@@ -1171,6 +1172,37 @@ This is the declarative counterpart of 'text-file*'."
(computed-file name build))
+(define (file-union name files)
+ "Return a <computed-file> that builds a directory containing all of FILES.
+Each item in FILES must be a two-element list where the first element is the
+file name to use in the new directory, and the second element is a gexp
+denoting the target file. Here's an example:
+
+ (file-union \"etc\"
+ `((\"hosts\" ,(plain-file \"hosts\"
+ \"127.0.0.1 localhost\"))
+ (\"bashrc\" ,(plain-file \"bashrc\"
+ \"alias ls='ls --color'\"))))
+
+This yields an 'etc' directory containing these two files."
+ (computed-file name
+ (gexp
+ (begin
+ (mkdir (ungexp output))
+ (chdir (ungexp output))
+ (ungexp-splicing
+ (map (match-lambda
+ ((target source)
+ (gexp
+ (begin
+ ;; Stat the source to abort early if it does
+ ;; not exist.
+ (stat (ungexp source))
+
+ (symlink (ungexp source)
+ (ungexp target))))))
+ files))))))
+
;;;
;;; Syntactic sugar.