utils: Add call-with-current-directory utility function.

* tissue/utils.scm (call-with-current-directory): New public function.

1 files changed, 10 insertions, 1 deletions

diff --git a/tissue/utils.scm b/tissue/utils.scm
index 6832fb8..156d333 100644
--- a/tissue/utils.scm
+++ b/tissue/utils.scm
@@ -20,10 +20,19 @@
   #:use-module (rnrs io ports)
   #:use-module (srfi srfi-26)
   #:use-module (ice-9 popen)
-  #:export (call-with-input-pipe
+  #:export (call-with-current-directory
+            call-with-input-pipe
             get-line-dos-or-unix
             memoize-thunk))
 
+(define (call-with-current-directory curdir thunk)
+  "Call THUNK with current directory set to CURDIR. Restore current
+directory after THUNK returns."
+  (let ((original-current-directory (getcwd)))
+    (dynamic-wind (cut chdir curdir)
+                  thunk
+                  (cut chdir original-current-directory))))
+
 (define (call-with-input-pipe proc program . args)
   "Execute PROGRAM ARGS ... in a subprocess with a pipe to it. Call
 PROC with an input port to that pipe. Close the pipe once PROC exits,