Move let-env to own module.

1 files changed, 25 insertions, 0 deletions

diff --git a/module/hnh/util/env.scm b/module/hnh/util/env.scm
new file mode 100644
index 00000000..a6877186
--- /dev/null
+++ b/module/hnh/util/env.scm
@@ -0,0 +1,25 @@
+(define-module (hnh util env)
+  :export (let-env))
+
+(define-syntax let-env
+  (syntax-rules ()
+    [(_ ((name value) ...)
+        body ...)
+
+     (let ((env-pairs #f))
+       (dynamic-wind
+         (lambda ()
+           (set! env-pairs
+             (map (lambda (n new-value)
+                    (list n new-value (getenv n)))
+                  (list (symbol->string (quote name)) ...)
+                  (list value ...)))
+           (for-each (lambda (pair) (setenv (car pair) (cadr pair)))
+                     env-pairs))
+         (lambda () body ...)
+         (lambda ()
+           (for-each (lambda (pair) (setenv (car pair) (caddr pair)))
+                     env-pairs))))]))
+
+
+