Index: openacs-4/packages/calendar/tcl/cal-item-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/calendar/tcl/cal-item-procs.tcl,v
diff -u -N -r1.34 -r1.35
--- openacs-4/packages/calendar/tcl/cal-item-procs.tcl	11 Jul 2018 20:45:30 -0000	1.34
+++ openacs-4/packages/calendar/tcl/cal-item-procs.tcl	24 Aug 2018 10:32:19 -0000	1.35
@@ -302,6 +302,9 @@
 } {
     Delete the calendar item
 } {
+    callback calendar::item::before_delete \
+        -cal_item_id $cal_item_id
+
     db_exec_plsql delete_cal_item {}
 }
 
Index: openacs-4/packages/calendar/tcl/calendar-callback-hooks-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/calendar/tcl/calendar-callback-hooks-procs.tcl,v
diff -u -N
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ openacs-4/packages/calendar/tcl/calendar-callback-hooks-procs.tcl	24 Aug 2018 10:32:19 -0000	1.1
@@ -0,0 +1,15 @@
+ad_library {
+
+    Callback hooks for the calendar package
+
+}
+
+namespace eval calendar {}
+namespace eval calendar::item {}
+
+ad_proc -public -callback calendar::item::before_delete {
+    {-cal_item_id:required}
+} {
+    Puts extra logics before calendar item deletion.
+} -
+