Index: openacs-4/packages/categories/tcl/category-form-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/categories/tcl/category-form-procs.tcl,v
diff -u -N -r1.8 -r1.9
--- openacs-4/packages/categories/tcl/category-form-procs.tcl	7 Aug 2017 23:48:05 -0000	1.8
+++ openacs-4/packages/categories/tcl/category-form-procs.tcl	29 Nov 2019 14:28:48 -0000	1.9
@@ -43,7 +43,7 @@
                        {label $name} \
                        {category_tree_id $tree_id} \
                        {category_subtree_id $subtree_id} \
-                       {category_object_id {[value_if_exists categorized_object_id]}} \
+                       {category_object_id {[expr {[info exists categorized_object_id] ? $categorized_object_id : ""}]}} \
 		       {category_assign_single_p $assign_single_p} \
 		       {category_require_category_p $require_category_p} \
                        {category_widget $widget} \
Index: openacs-4/packages/categories/www/cadmin/category-delete.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/categories/www/cadmin/category-delete.tcl,v
diff -u -N -r1.14 -r1.15
--- openacs-4/packages/categories/www/cadmin/category-delete.tcl	29 Jun 2018 17:27:18 -0000	1.14
+++ openacs-4/packages/categories/www/cadmin/category-delete.tcl	29 Nov 2019 14:28:48 -0000	1.15
@@ -39,8 +39,8 @@
 set page_title "Delete categories"
 
 set context_bar [category::context_bar $tree_id $locale \
-                     [value_if_exists object_id] \
-                     [value_if_exists ctx_id]]
+                     [expr {[info exists object_id] ? $object_id : ""}] \
+                     [expr {[info exists ctx_id] ? $ctx_id : ""}]]
 lappend context_bar "Delete categories"
 
 template::list::create \
Index: openacs-4/packages/categories/www/cadmin/category-form.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/categories/www/cadmin/category-form.tcl,v
diff -u -N -r1.15 -r1.16
--- openacs-4/packages/categories/www/cadmin/category-form.tcl	12 Feb 2019 17:12:19 -0000	1.15
+++ openacs-4/packages/categories/www/cadmin/category-form.tcl	29 Nov 2019 14:28:48 -0000	1.16
@@ -26,8 +26,8 @@
 }
 
 set context_bar [category::context_bar $tree_id $locale \
-                     [value_if_exists object_id] \
-                     [value_if_exists ctx_id]]
+                     [expr {[info exists object_id] ? $object_id : ""}] \
+                     [expr {[info exists ctx_id] ? $ctx_id : ""}]]
 lappend context_bar $page_title
 
 set languages [lang::system::get_locale_options]
Index: openacs-4/packages/categories/www/cadmin/category-link-add-2.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/categories/www/cadmin/category-link-add-2.tcl,v
diff -u -N -r1.11 -r1.12
--- openacs-4/packages/categories/www/cadmin/category-link-add-2.tcl	29 Jun 2018 17:27:18 -0000	1.11
+++ openacs-4/packages/categories/www/cadmin/category-link-add-2.tcl	29 Nov 2019 14:28:48 -0000	1.12
@@ -29,8 +29,8 @@
 set page_title "Add link from \"$link_tree_name\" to category \"$tree_name :: $category_name\""
 
 set context_bar [category::context_bar $tree_id $locale \
-                     [value_if_exists object_id] \
-                     [value_if_exists ctx_id]]
+                     [expr {[info exists object_id] ? $object_id : ""}] \
+                     [expr {[info exists ctx_id] ? $ctx_id : ""}]]
 lappend context_bar \
     [list [export_vars -no_empty -base category-links-view {category_id tree_id locale object_id ctx_id}] "Links to $category_name"] \
     [list [export_vars -no_empty -base category-link-add {category_id tree_id locale object_id ctx_id}] "Select link target"] \
Index: openacs-4/packages/categories/www/cadmin/category-link-add.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/categories/www/cadmin/category-link-add.tcl,v
diff -u -N -r1.7 -r1.8
--- openacs-4/packages/categories/www/cadmin/category-link-add.tcl	29 Jun 2018 17:27:18 -0000	1.7
+++ openacs-4/packages/categories/www/cadmin/category-link-add.tcl	29 Nov 2019 14:28:48 -0000	1.8
@@ -25,8 +25,8 @@
 set page_title "Select target to add a link to category \"$tree_name :: $category_name\""
 
 set context_bar [category::context_bar $tree_id $locale \
-                     [value_if_exists object_id] \
-                     [value_if_exists ctx_id]]
+                     [expr {[info exists object_id] ? $object_id : ""}] \
+                     [expr {[info exists ctx_id] ? $ctx_id : ""}]]
 lappend context_bar \
     [list [export_vars -no_empty -base category-links-view {category_id tree_id locale object_id  ctx_id}] "Links to $category_name"] \
     "Select link target"
Index: openacs-4/packages/categories/www/cadmin/category-link-delete.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/categories/www/cadmin/category-link-delete.tcl,v
diff -u -N -r1.9 -r1.10
--- openacs-4/packages/categories/www/cadmin/category-link-delete.tcl	29 Jun 2018 17:27:18 -0000	1.9
+++ openacs-4/packages/categories/www/cadmin/category-link-delete.tcl	29 Nov 2019 14:28:48 -0000	1.10
@@ -29,8 +29,8 @@
 set page_title "Delete links with category \"$tree_name :: $category_name\""
 
 set context_bar [category::context_bar $tree_id $locale \
-                     [value_if_exists object_id] \
-                     [value_if_exists ctx_id]]
+                     [expr {[info exists object_id] ? $object_id : ""}] \
+                     [expr {[info exists ctx_id] ? $ctx_id : ""}]]
 lappend context_bar \
     [list [export_vars -no_empty -base category-links-view {category_id tree_id locale object_id  ctx_id}] "Links to $category_name"] \
     "Delete Links"
Index: openacs-4/packages/categories/www/cadmin/category-links-view.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/categories/www/cadmin/category-links-view.tcl,v
diff -u -N -r1.11 -r1.12
--- openacs-4/packages/categories/www/cadmin/category-links-view.tcl	29 Jun 2018 17:27:18 -0000	1.11
+++ openacs-4/packages/categories/www/cadmin/category-links-view.tcl	29 Nov 2019 14:28:48 -0000	1.12
@@ -25,8 +25,8 @@
 set page_title "Categories linked with category \"$tree_name :: $category_name\""
 
 set context_bar [category::context_bar $tree_id $locale \
-                     [value_if_exists object_id] \
-                     [value_if_exists ctx_id]]
+                     [expr {[info exists object_id] ? $object_id : ""}] \
+                     [expr {[info exists ctx_id] ? $ctx_id : ""}]]
 lappend context_bar "Links to $category_name"
 
 
Index: openacs-4/packages/categories/www/cadmin/category-parent-change.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/categories/www/cadmin/category-parent-change.tcl,v
diff -u -N -r1.8 -r1.9
--- openacs-4/packages/categories/www/cadmin/category-parent-change.tcl	29 Jun 2018 17:27:18 -0000	1.8
+++ openacs-4/packages/categories/www/cadmin/category-parent-change.tcl	29 Nov 2019 14:28:48 -0000	1.9
@@ -23,8 +23,8 @@
 set category_name [category::get_name $category_id $locale]
 set page_title "Change parent category of \"$category_name\""
 set context_bar [category::context_bar $tree_id $locale \
-                     [value_if_exists object_id] \
-                     [value_if_exists ctx_id]]
+                     [expr {[info exists object_id] ? $object_id : ""}] \
+                     [expr {[info exists ctx_id] ? $ctx_id : ""}]]
 lappend context_bar "Change parent"
 
 
Index: openacs-4/packages/categories/www/cadmin/category-usage.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/categories/www/cadmin/category-usage.tcl,v
diff -u -N -r1.10 -r1.11
--- openacs-4/packages/categories/www/cadmin/category-usage.tcl	29 Jun 2018 17:27:18 -0000	1.10
+++ openacs-4/packages/categories/www/cadmin/category-usage.tcl	29 Nov 2019 14:28:48 -0000	1.11
@@ -36,7 +36,7 @@
 set page_title "Objects using category \"$category_name\" of tree \"$tree_name\""
 set url_vars [export_vars -no_empty {category_id tree_id locale object_id}]
 
-set context_bar [category::context_bar $tree_id $locale [value_if_exists object_id]]
+set context_bar [category::context_bar $tree_id $locale [expr {[info exists object_id] ? $object_id : ""}]]
 lappend context_bar "\"$category_name\" Usage"
 
 template::list::create -name items_list -multirow items \
Index: openacs-4/packages/categories/www/cadmin/permission-manage.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/categories/www/cadmin/permission-manage.tcl,v
diff -u -N -r1.9 -r1.10
--- openacs-4/packages/categories/www/cadmin/permission-manage.tcl	29 Jun 2018 17:27:18 -0000	1.9
+++ openacs-4/packages/categories/www/cadmin/permission-manage.tcl	29 Nov 2019 14:28:48 -0000	1.10
@@ -22,7 +22,7 @@
 set tree_name $tree(tree_name)
 set page_title [_ categories.Permissions_manage_title]
 
-set context_bar [category::context_bar $tree_id $locale [value_if_exists object_id]]
+set context_bar [category::context_bar $tree_id $locale [expr {[info exists object_id] ? $object_id : ""}]]
 lappend context_bar [_ categories.Permissions_manage]
 
 set url_vars [export_vars {tree_id object_id locale}]
Index: openacs-4/packages/categories/www/cadmin/synonym-delete.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/categories/www/cadmin/synonym-delete.tcl,v
diff -u -N -r1.6 -r1.7
--- openacs-4/packages/categories/www/cadmin/synonym-delete.tcl	29 Jun 2018 17:27:18 -0000	1.6
+++ openacs-4/packages/categories/www/cadmin/synonym-delete.tcl	29 Nov 2019 14:28:48 -0000	1.7
@@ -27,8 +27,8 @@
 set page_title "Delete synonyms of category \"$tree_name :: $category_name\""
 
 set context_bar [category::context_bar $tree_id $locale \
-                     [value_if_exists object_id] \
-                     [value_if_exists ctx_id]]
+                     [expr {[info exists object_id] ? $object_id : ""}] \
+                     [expr {[info exists ctx_id] ? $ctx_id : ""}]]
 lappend context_bar [list [export_vars -no_empty -base synonyms-view { category_id tree_id locale object_id ctx_id}] "Synonyms of $category_name"] "Delete synonyms"
 
 set delete_url [export_vars -no_empty -base synonym-delete-2 { synonym_id:multiple category_id tree_id locale object_id ctx_id}]
Index: openacs-4/packages/categories/www/cadmin/synonym-form.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/categories/www/cadmin/synonym-form.tcl,v
diff -u -N -r1.8 -r1.9
--- openacs-4/packages/categories/www/cadmin/synonym-form.tcl	29 Jun 2018 17:27:18 -0000	1.8
+++ openacs-4/packages/categories/www/cadmin/synonym-form.tcl	29 Nov 2019 14:28:48 -0000	1.9
@@ -30,8 +30,8 @@
 set page_title "$action category synonym of \"$tree_name :: $category_name\""
 
 set context_bar [category::context_bar $tree_id $locale \
-                     [value_if_exists object_id] \
-                     [value_if_exists ctx_id]]
+                     [expr {[info exists object_id] ? $object_id : ""}] \
+                     [expr {[info exists ctx_id] ? $ctx_id : ""}]]
 
 lappend context_bar [list [export_vars -no_empty -base synonyms-view { category_id tree_id locale object_id ctx_id}] "Synonyms of $category_name"] "$action synonym"
 
Index: openacs-4/packages/categories/www/cadmin/synonyms-view.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/categories/www/cadmin/synonyms-view.tcl,v
diff -u -N -r1.8 -r1.9
--- openacs-4/packages/categories/www/cadmin/synonyms-view.tcl	29 Jun 2018 17:27:18 -0000	1.8
+++ openacs-4/packages/categories/www/cadmin/synonyms-view.tcl	29 Nov 2019 14:28:48 -0000	1.9
@@ -25,8 +25,8 @@
 set page_title "Synonyms for category \"$tree_name :: $category_name\""
 
 set context_bar [category::context_bar $tree_id $locale \
-                     [value_if_exists object_id] \
-                     [value_if_exists ctx_id]]
+                     [expr {[info exists object_id] ? $object_id : ""}] \
+                     [expr {[info exists ctx_id] ? $ctx_id : ""}]]
 lappend context_bar "Synonyms of $category_name"
 
 
Index: openacs-4/packages/categories/www/cadmin/tree-copy-view.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/categories/www/cadmin/tree-copy-view.tcl,v
diff -u -N -r1.7 -r1.8
--- openacs-4/packages/categories/www/cadmin/tree-copy-view.tcl	29 Jun 2018 17:27:18 -0000	1.7
+++ openacs-4/packages/categories/www/cadmin/tree-copy-view.tcl	29 Nov 2019 14:28:48 -0000	1.8
@@ -31,8 +31,8 @@
 set page_title [_ categories.Tree_view_title]
 
 set context_bar [category::context_bar $tree_id $locale \
-                     [value_if_exists object_id] \
-                     [value_if_exists ctx_id]]
+                     [expr {[info exists object_id] ? $object_id : ""}] \
+                     [expr {[info exists ctx_id] ? $ctx_id : ""}]]
 lappend context_bar [list \
 			 [export_vars -no_empty -base tree-copy { {tree_id $target_tree_id} locale object_id ctx_id }] \
 			 [_ categories.Action_copy_tree]] \
Index: openacs-4/packages/categories/www/cadmin/tree-copy.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/categories/www/cadmin/tree-copy.tcl,v
diff -u -N -r1.15 -r1.16
--- openacs-4/packages/categories/www/cadmin/tree-copy.tcl	29 Jun 2018 17:27:18 -0000	1.15
+++ openacs-4/packages/categories/www/cadmin/tree-copy.tcl	29 Nov 2019 14:28:48 -0000	1.16
@@ -25,8 +25,8 @@
 set page_title [_ categories.Tree_copy_title]
 
 set context_bar [category::context_bar $tree_id $locale \
-                     [value_if_exists object_id] \
-                     [value_if_exists ctx_id]]
+                     [expr {[info exists object_id] ? $object_id : ""}] \
+                     [expr {[info exists ctx_id] ? $ctx_id : ""}]]
 lappend context_bar [_ categories.Tree_copy]
 
 template::multirow create trees tree_id tree_name site_wide_p view_url copy_url
Index: openacs-4/packages/categories/www/cadmin/tree-delete.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/categories/www/cadmin/tree-delete.tcl,v
diff -u -N -r1.14 -r1.15
--- openacs-4/packages/categories/www/cadmin/tree-delete.tcl	29 Jun 2018 17:27:18 -0000	1.14
+++ openacs-4/packages/categories/www/cadmin/tree-delete.tcl	29 Nov 2019 14:28:48 -0000	1.15
@@ -30,8 +30,8 @@
 
 set page_title [_ categories.Delete_category_tree_title]
 set context_bar [category::context_bar $tree_id $locale \
-                     [value_if_exists object_id] \
-                     [value_if_exists ctx_id]]
+                     [expr {[info exists object_id] ? $object_id : ""}] \
+                     [expr {[info exists ctx_id] ? $ctx_id : ""}]]
 lappend context_bar [_ categories.Delete]
 
 set instance_list [category_tree::usage $tree_id]
Index: openacs-4/packages/categories/www/cadmin/tree-usage.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/categories/www/cadmin/tree-usage.tcl,v
diff -u -N -r1.13 -r1.14
--- openacs-4/packages/categories/www/cadmin/tree-usage.tcl	29 Jun 2018 17:27:19 -0000	1.13
+++ openacs-4/packages/categories/www/cadmin/tree-usage.tcl	29 Nov 2019 14:28:48 -0000	1.14
@@ -31,8 +31,8 @@
 set page_title [_ categories.Usage_title]
 
 set context_bar [category::context_bar $tree_id $locale \
-                     [value_if_exists object_id] \
-                     [value_if_exists ctx_id]]
+                     [expr {[info exists object_id] ? $object_id : ""}] \
+                     [expr {[info exists ctx_id] ? $ctx_id : ""}]]
 lappend context_bar [_ categories.Usage]
 
 
Index: openacs-4/packages/dotlrn-ecommerce/www/admin/ecommerce/invoice-payment.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/dotlrn-ecommerce/www/admin/ecommerce/invoice-payment.tcl,v
diff -u -N -r1.9 -r1.10
--- openacs-4/packages/dotlrn-ecommerce/www/admin/ecommerce/invoice-payment.tcl	20 Nov 2019 14:06:41 -0000	1.9
+++ openacs-4/packages/dotlrn-ecommerce/www/admin/ecommerce/invoice-payment.tcl	29 Nov 2019 14:28:48 -0000	1.10
@@ -216,8 +216,8 @@
     } else {
 	set billing_address_id 0 
 	# no previous billing address, set defaults
-	set bill_to_first_names [value_if_exists first_names]
-	set bill_to_last_name [value_if_exists last_name]
+	set bill_to_first_names [expr {[info exists first_names] ? $first_names : ""}]
+	set bill_to_last_name [expr {[info exists last_name] ? $last_name : ""}]
 
 	set bill_to_line1 ""
 	set bill_to_line2 ""
Index: openacs-4/packages/dotlrn-ecommerce/www/ecommerce/checkout-one-form-2.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/dotlrn-ecommerce/www/ecommerce/checkout-one-form-2.tcl,v
diff -u -N -r1.13 -r1.14
--- openacs-4/packages/dotlrn-ecommerce/www/ecommerce/checkout-one-form-2.tcl	12 Aug 2005 10:09:32 -0000	1.13
+++ openacs-4/packages/dotlrn-ecommerce/www/ecommerce/checkout-one-form-2.tcl	29 Nov 2019 14:28:48 -0000	1.14
@@ -222,7 +222,7 @@
 regsub -all { +} $bill_to_last_name " " bill_to_last_name
 set bill_to_attn "[string trim $bill_to_first_names]   [string trim $bill_to_last_name]"
 
-if { [value_if_exists billing_address_id] > 0} {
+if { [expr {[info exists billing_address_id] ? $billing_address_id : ""}] > 0} {
 
     # This is an existing address that might have been edited
 
Index: openacs-4/packages/dotlrn-ecommerce/www/ecommerce/checkout-one-form.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/dotlrn-ecommerce/www/ecommerce/checkout-one-form.tcl,v
diff -u -N -r1.26 -r1.27
--- openacs-4/packages/dotlrn-ecommerce/www/ecommerce/checkout-one-form.tcl	20 Nov 2019 14:06:41 -0000	1.26
+++ openacs-4/packages/dotlrn-ecommerce/www/ecommerce/checkout-one-form.tcl	29 Nov 2019 14:28:48 -0000	1.27
@@ -663,8 +663,8 @@
     } else {
 	set billing_address_id 0 
 	# no previous billing address, set defaults
-	set bill_to_first_names [value_if_exists first_names]
-	set bill_to_last_name [value_if_exists last_name]
+	set bill_to_first_names [expr {[info exists first_names] ? $first_names : ""}]
+	set bill_to_last_name [expr {[info exists last_name] ? $last_name : ""}]
 
 	set bill_to_line1 ""
 	set bill_to_line2 ""
Index: openacs-4/packages/dotlrn-ecommerce/www/ecommerce/shopping-cart-add.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/dotlrn-ecommerce/www/ecommerce/shopping-cart-add.tcl,v
diff -u -N -r1.38 -r1.39
--- openacs-4/packages/dotlrn-ecommerce/www/ecommerce/shopping-cart-add.tcl	24 May 2018 07:06:08 -0000	1.38
+++ openacs-4/packages/dotlrn-ecommerce/www/ecommerce/shopping-cart-add.tcl	29 Nov 2019 14:28:48 -0000	1.39
@@ -306,7 +306,7 @@
 # order_id to be the empty string (if it is, log the error and
 # redirect them to product.tcl).
 
-if { [value_if_exists order_id] < 1 || [ad_var_type_check_number_p $order_id] == 0 } {
+if { [expr {[info exists order_id] ? $order_id : ""}] < 1 || [ad_var_type_check_number_p $order_id] == 0 } {
     set order_id [db_nextval ec_order_id_sequence]
   
     # Create the order (if an in_basket order *still* doesn't exist)
Index: openacs-4/packages/dotlrn-ecommerce/www/manage/ecommerce/invoice-payment.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/dotlrn-ecommerce/www/manage/ecommerce/invoice-payment.tcl,v
diff -u -N -r1.4 -r1.5
--- openacs-4/packages/dotlrn-ecommerce/www/manage/ecommerce/invoice-payment.tcl	20 Nov 2019 14:06:41 -0000	1.4
+++ openacs-4/packages/dotlrn-ecommerce/www/manage/ecommerce/invoice-payment.tcl	29 Nov 2019 14:28:48 -0000	1.5
@@ -216,8 +216,8 @@
     } else {
 	set billing_address_id 0 
 	# no previous billing address, set defaults
-	set bill_to_first_names [value_if_exists first_names]
-	set bill_to_last_name [value_if_exists last_name]
+	set bill_to_first_names [expr {[info exists first_names] ? $first_names : ""}]
+	set bill_to_last_name [expr {[info exists last_name] ? $last_name : ""}]
 
 	set bill_to_line1 ""
 	set bill_to_line2 ""