Index: openacs-4/packages/acs-tcl/tcl/callback-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/acs-tcl/tcl/callback-procs.tcl,v
diff -u -r1.1 -r1.2
--- openacs-4/packages/acs-tcl/tcl/callback-procs.tcl	11 Apr 2005 22:21:21 -0000	1.1
+++ openacs-4/packages/acs-tcl/tcl/callback-procs.tcl	27 Oct 2014 16:40:06 -0000	1.2
@@ -12,9 +12,7 @@
 } {
     Returns whether the specified implementation exists.
 } {
-    return [expr {![string equal \
-        [info commands ::callback::${callback}::impl::${impl}] \
-        ""]}]
+    return [expr {[info commands ::callback::${callback}::impl::${impl}] ne ""}]
 }
 
 ad_proc -public callback::get_object_type_impl {