Add file-extension, absolute-file-name, and tmpdir utility procedures.

1 files changed, 17 insertions, 1 deletions

diff --git a/chickadee/utils.scm b/chickadee/utils.scm
index 8869e8d..2d218c4 100644
--- a/chickadee/utils.scm
+++ b/chickadee/utils.scm
@@ -17,9 +17,25 @@
 ;;; <http://www.gnu.org/licenses/>.
 
 (define-module (chickadee utils)
-  #:export (memoize
+  #:use-module (ice-9 match)
+  #:export (file-extension
+            absolute-file-name
+            tmpdir
+            memoize
             for-range))
 
+(define (file-extension file-name)
+  (match (string-split file-name #\.)
+    ((_ ... ext) ext)))
+
+(define (absolute-file-name file-name)
+  (if (absolute-file-name? file-name)
+      file-name
+      (string-append (getcwd) "/" file-name)))
+
+(define (tmpdir)
+  (or (getenv "TMPDIR") "/tmp"))
+
 ;; Written by Ludovic Courtès.  Taken from GNU Guix.
 (define (memoize proc)
   "Return a memoizing version of PROC."