* boot-9.scm (remove-hook!): New macro. (Thanks to Maciej

Stachowiak.)

diff --git a/ice-9/ChangeLog b/ice-9/ChangeLog
index da7093b..baeb902 100644 (file)
--- a/ice-9/ChangeLog
+++ b/ice-9/ChangeLog
@@ -1,3 +1,8 @@
+1998-03-28  Mikael Djurfeldt  <mdj@mdj.nada.kth.se>
+
+       * boot-9.scm (remove-hook!): New macro.  (Thanks to Maciej
+       Stachowiak.)
+
 1998-01-30  Mikael Djurfeldt  <mdj@mdj.nada.kth.se>
 
        * threads.scm: Added simple error and signal handler.

diff --git a/ice-9/boot-9.scm b/ice-9/boot-9.scm
index 1b59fae..bef6126 100644 (file)
--- a/ice-9/boot-9.scm
+++ b/ice-9/boot-9.scm
@@ -550,6 +550,14 @@
             (set! ,(cadr exp)
                   (cons thunk ,(cadr exp))))))))
 
+(define remove-hook!
+  (procedure->macro
+    (lambda (exp env)
+      `(let ((thunk ,(caddr exp)))
+        (if (memq thunk ,(cadr exp)))
+        (set! ,(cadr exp)
+              (delq! thunk ,(cadr exp)))))))
+
 \f
 ;;; {Files}
 ;;;