Index: openacs-4/packages/acs-tcl/tcl/memoize-procs-aolserver.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/acs-tcl/tcl/memoize-procs-aolserver.tcl,v
diff -u -r1.1 -r1.2
--- openacs-4/packages/acs-tcl/tcl/memoize-procs-aolserver.tcl	26 Feb 2018 18:46:41 -0000	1.1
+++ openacs-4/packages/acs-tcl/tcl/memoize-procs-aolserver.tcl	11 Feb 2019 10:11:45 -0000	1.2
@@ -24,30 +24,39 @@
 
     @return The possibly-cached value returned by <i>script</i>.
 } {
+    #
+    # The ::util_memoize_flush proc is defined in the *-init script,
+    # after the util_memoize cache was created. Therefore is save to
+    # use the util_memoize when this proc is available.
+    #
+    if {[info commands ::util_memoize_flush] ne ""} {
 
-    if {$max_age ne "" && $max_age < 0} {
-	error "max_age must not be negative"
-    }
+        if {$max_age ne "" && $max_age < 0} {
+            error "max_age must not be negative"
+        }
 
-    set current_time [ns_time]
+        set current_time [ns_time]
 
-    set cached_p [ns_cache get util_memoize $script pair]
+        set cached_p [ns_cache get util_memoize $script pair]
 
-    if {$cached_p && $max_age ne "" } {
-	set cache_time [lindex $pair 0]
-	if {$current_time - $cache_time > $max_age} {
-	    ns_cache flush util_memoize $script
-	    set cached_p 0
-	}
-    }
+        if {$cached_p && $max_age ne "" } {
+            set cache_time [lindex $pair 0]
+            if {$current_time - $cache_time > $max_age} {
+                ns_cache flush util_memoize $script
+                set cached_p 0
+            }
+        }
 
-    if {!$cached_p} {
-	set pair [ns_cache eval util_memoize $script {
-	    list $current_time [eval $script]
-	}]
-    }
+        if {!$cached_p} {
+            set pair [ns_cache eval util_memoize $script {
+                list $current_time [eval $script]
+            }]
+        }
 
-    return [lindex $pair 1]
+        return [lindex $pair 1]
+    } else {
+        uplevel $script
+    }
 }
 
 ad_proc -public util_memoize_seed {script value {max_age ""}} {
Index: openacs-4/packages/acs-tcl/tcl/memoize-procs-naviserver.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/acs-tcl/tcl/memoize-procs-naviserver.tcl,v
diff -u -r1.8 -r1.9
--- openacs-4/packages/acs-tcl/tcl/memoize-procs-naviserver.tcl	5 Aug 2018 21:08:42 -0000	1.8
+++ openacs-4/packages/acs-tcl/tcl/memoize-procs-naviserver.tcl	11 Feb 2019 10:11:45 -0000	1.9
@@ -53,10 +53,19 @@
 
     @return The possibly-cached value returned by <i>script</i>.
 } {
-    if {$max_age ne ""} {
-        set max_age "-expires $max_age"
+    #
+    # The ::util_memoize_flush proc is defined in the *-init script,
+    # after the util_memoize cache was created. Therefore is save to
+    # use the util_memoize when this proc is available.
+    #
+    if {[info commands ::util_memoize_flush] ne ""} {
+        if {$max_age ne ""} {
+            set max_age "-expires $max_age"
+        }
+        ns_cache_eval {*}$max_age -- util_memoize $script {*}$script
+    } else {
+        uplevel $script
     }
-    ns_cache_eval {*}$max_age -- util_memoize $script {*}$script
 }
 
 # In case, the definition of the function has cached something,