Index: openacs-4/packages/news-aggregator/tcl/aggregator-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/news-aggregator/tcl/aggregator-procs.tcl,v
diff -u -r1.3 -r1.4
--- openacs-4/packages/news-aggregator/tcl/aggregator-procs.tcl	7 Apr 2018 11:09:13 -0000	1.3
+++ openacs-4/packages/news-aggregator/tcl/aggregator-procs.tcl	7 Apr 2018 16:58:52 -0000	1.4
@@ -118,7 +118,7 @@
         $link_node appendChild $text_node
         $item_node appendChild $link_node
         
-        if { ![string equal $content_encoded ""] } {
+        if { $content_encoded ne "" } {
             set content $content_encoded
         } else {
             set content $item_description
@@ -155,7 +155,7 @@
     }
     
     set limit [parameter::get -package_id $package_id -parameter "number_of_items_shown"]
-    set sql_limit [expr $limit_multiple*$limit]
+    set sql_limit [expr {$limit_multiple*$limit}]
     
     set sql [db_map items]
     return $sql
@@ -292,9 +292,9 @@
 } {
     set aggregator_id [db_string find_default {} -default 0]
 
-    if { [string equal $aggregator_id "0"] } {
+    if {$aggregator_id eq "0"} {
         set aggregator_id [db_string lowest_aggregator ""]
-	if { [exists_and_not_null aggregator_id] } {
+	if { ([info exists aggregator_id] && $aggregator_id ne "") } {
 	    news_aggregator::aggregator::set_user_default \
 	  				-user_id $user_id \
 					-aggregator_id $aggregator_id
@@ -341,15 +341,15 @@
     @creation-date 2003-06-29
 } {
 
-    if { ![exists_and_not_null creation_user] } {
+    if { (![info exists creation_user] || $creation_user eq "") } {
         set creation_user [ad_conn user_id]
     }
 
-    if { ![exists_and_not_null creation_ip] } {
+    if { (![info exists creation_ip] || $creation_ip eq "") } {
         set creation_ip [ad_conn peeraddr]
     }
 
-    if { ![exists_and_not_null package_id] } {
+    if { (![info exists package_id] || $package_id eq "") } {
         set package_id [ad_conn package_id]
     }
 
Index: openacs-4/packages/news-aggregator/tcl/news-aggregator-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/news-aggregator/tcl/news-aggregator-procs.tcl,v
diff -u -r1.9 -r1.10
--- openacs-4/packages/news-aggregator/tcl/news-aggregator-procs.tcl	13 Jan 2005 13:58:27 -0000	1.9
+++ openacs-4/packages/news-aggregator/tcl/news-aggregator-procs.tcl	7 Apr 2018 16:58:52 -0000	1.10
@@ -32,10 +32,10 @@
     if {$diff < 120 && $diff > 60} {
         set to_return "1 hour and "
     } elseif {$diff >= 60} {
-        set to_return "[expr $diff / 60] hours and "
+        set to_return "[expr {$diff / 60}] hours and "
     }
-    set mins [expr $diff % 60]
-    if {[string equal 1 $mins]} {
+    set mins [expr {$diff % 60}]
+    if {"1" eq $mins} {
         append to_return "1 minute ago"
     } else {
         append to_return "$mins minutes ago"
Index: openacs-4/packages/news-aggregator/tcl/opml-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/news-aggregator/tcl/opml-procs.tcl,v
diff -u -r1.1 -r1.2
--- openacs-4/packages/news-aggregator/tcl/opml-procs.tcl	20 Mar 2004 11:04:39 -0000	1.1
+++ openacs-4/packages/news-aggregator/tcl/opml-procs.tcl	7 Apr 2018 16:58:52 -0000	1.2
@@ -20,7 +20,7 @@
         set doc [dom parse $xml]
         
         set doc_node [$doc documentElement]
-        if { ![string equal [$doc_node nodeName] "opml"] } {
+        if { [$doc_node nodeName] ne "opml" } {
             error "Document element is not opml"
         }
         
@@ -36,7 +36,7 @@
             error "There is not exactly one title element in head: $title_texts"
         }
         set title_text [[lindex $title_texts 0] nodeValue]
-        if { ![string equal $title_text "mySubscriptions"] } {
+        if { $title_text ne "mySubscriptions" } {
             error "OPML title is not 'mySubscriptions'. This does not appear to be an OPML file in mySubscriptions format."
         }
         
@@ -55,8 +55,8 @@
             set url [$node getAttribute xmlUrl ""]
             set html_url [$node getAttribute htmlUrl ""]
             
-            if { ![string equal $title ""] && ![string equal url ""] &&
-                 ![string equal $html_url ""] &&
+            if { $title ne "" && ![string equal url ""] &&
+                 $html_url ne "" &&
                  [util_url_valid_p $url] } {
                 set feed(title) $title
                 set feed(url) $url
Index: openacs-4/packages/news-aggregator/tcl/source-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/news-aggregator/tcl/source-procs.tcl,v
diff -u -r1.7 -r1.8
--- openacs-4/packages/news-aggregator/tcl/source-procs.tcl	7 Apr 2018 11:09:13 -0000	1.7
+++ openacs-4/packages/news-aggregator/tcl/source-procs.tcl	7 Apr 2018 16:58:52 -0000	1.8
@@ -25,7 +25,7 @@
 
     if { [db_0or1row source {}] } {
         ns_log Debug "news_aggregator::source::new: Source exists"
-        if { [exists_and_not_null aggregator_id] } {
+        if { ([info exists aggregator_id] && $aggregator_id ne "") } {
             ns_log Debug "news_aggregator::source::new: Source exists, creating new subscription"
             news_aggregator::subscription::new \
                 -aggregator_id $aggregator_id \
@@ -49,7 +49,7 @@
 
     array set f [ad_httpget -url $feed_url -depth 4]
 
-    if { ![string equal 200 $f(status)] || [catch { array set result [feed_parser::parse_feed -xml $f(page)] }] } {
+    if { "200" ne $f(status) || [catch { array set result [feed_parser::parse_feed -xml $f(page)] }] } {
         ns_log Debug "news_aggregator::source::new: Couldn't httpget, status = $f(status)"
         return 0
     }
@@ -69,7 +69,7 @@
 
     update -source_id $source_id -feed_url $feed_url -modified ""
     
-    if { [exists_and_not_null aggregator_id] } {
+    if { ([info exists aggregator_id] && $aggregator_id ne "") } {
         news_aggregator::subscription::new \
             -aggregator_id $aggregator_id \
             -source_id $source_id
@@ -103,13 +103,13 @@
     {-domain:required}
     {-description:required}
 } {
-    if { [exists_and_not_null guid] } {
+    if { ([info exists guid] && $guid ne "") } {
         return guid
-    } elseif { [exists_and_not_null link] && [news_aggregator::check_link \
+    } elseif { ([info exists link] && $link ne "") && [news_aggregator::check_link \
                                                   -link $link \
                                                   -domain $domain] } {
         return link
-    } elseif { [exists_and_not_null description]  } {
+    } elseif { ([info exists description] && $description ne "")  } {
         return description
     }
 }
@@ -137,7 +137,7 @@
         return
     }
 
-    if { ![string equal 200 $f(status)] } {
+    if { "200" ne $f(status) } {
 	ns_log Debug "source::update: httpget didn't return 200 but $f(status)"
 	return
     }
@@ -221,8 +221,8 @@
         }
         
         if { (!$new_p
-          && (![string equal $db_title $title] ||
-              ![string equal $db_description $description]))
+          && ($db_title ne $title ||
+              $db_description ne $description ))
                         ||
                     $new_p } {
             set updated_p 1
@@ -277,7 +277,7 @@
     Generate a private GUID for an entry that is used only
     by news-aggregator.
 } {
-    if { ![exists_and_not_null guid] } {
+    if { (![info exists guid] || $guid eq "") } {
         set message [list $title $link $description]
         set guid [ns_sha1 $message]
     }
@@ -309,7 +309,7 @@
         set source_count [db_string source_count ""]
         if { $source_count >= 1 } {
             if { !$all_sources_p } {
-                set limit [expr int($source_count/4)]
+                set limit [expr {int($source_count/4)}]
                 if { $limit < 1 } {
                     set limit 1
                 }
Index: openacs-4/packages/news-aggregator/tcl/weblog-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/news-aggregator/tcl/weblog-procs.tcl,v
diff -u -r1.1 -r1.2
--- openacs-4/packages/news-aggregator/tcl/weblog-procs.tcl	20 Mar 2004 11:04:39 -0000	1.1
+++ openacs-4/packages/news-aggregator/tcl/weblog-procs.tcl	7 Apr 2018 16:58:52 -0000	1.2
@@ -22,13 +22,13 @@
     @author Simon Carstensen (simon@bcuni.net)
     @creation-date 2003-07-14
 } {
-    if { [empty_string_p $package_id]} {
+    if { $package_id eq ""} {
         set package_id [ad_conn package_id]
     }
-    if { [empty_string_p $user_id]} {
+    if { $user_id eq ""} {
         set user_id [ad_conn user_id]
     }
-    if { [empty_string_p $ip]} {
+    if { $ip eq ""} {
 	set ip [ns_conn peeraddr]
     }
 
Index: openacs-4/packages/news-aggregator/www/aggregator-delete.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/news-aggregator/www/aggregator-delete.tcl,v
diff -u -r1.1 -r1.2
--- openacs-4/packages/news-aggregator/www/aggregator-delete.tcl	20 Mar 2004 11:04:39 -0000	1.1
+++ openacs-4/packages/news-aggregator/www/aggregator-delete.tcl	7 Apr 2018 16:58:52 -0000	1.2
@@ -13,11 +13,11 @@
 set user_id [ad_conn user_id]
 set default_aggregator [db_string find_default {}]
 
-if { [string equal $delete_aggregator_id $default_aggregator] } {
+if {$delete_aggregator_id eq $default_aggregator} {
     # We are deleting the user's default aggregator
     # Set user's oldest aggregator as new default
     set new_default_aggregator [db_string select_oldest_aggregator {} -default ""]
-    if { [exists_and_not_null $new_default_aggregator] } {
+    if { ([info exists $new_default_aggregator] && $$new_default_aggregator ne "") } {
         news_aggregator::aggregator::set_user_default \
             -user_id $user_id \
             -aggregator_id $new_default_aggregator
Index: openacs-4/packages/news-aggregator/www/aggregator.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/news-aggregator/www/aggregator.tcl,v
diff -u -r1.4 -r1.5
--- openacs-4/packages/news-aggregator/www/aggregator.tcl	1 Mar 2005 00:01:39 -0000	1.4
+++ openacs-4/packages/news-aggregator/www/aggregator.tcl	7 Apr 2018 16:58:52 -0000	1.5
@@ -45,7 +45,7 @@
         -description $description \
         -public_p $public_p
     
-    if { [exists_and_not_null return_url] } {
+    if { ([info exists return_url] && $return_url ne "") } {
         ad_returnredirect $return_url
     } else {
         ad_returnredirect settings
@@ -58,7 +58,7 @@
                                -description $description \
                                -public_p $public_p]
     
-    if { [exists_and_not_null return_url] } {
+    if { ([info exists return_url] && $return_url ne "") } {
         ad_returnredirect $return_url
     } else {
         ad_returnredirect "[ad_conn package_url]$new_aggregator_id"
Index: openacs-4/packages/news-aggregator/www/index.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/news-aggregator/www/index.tcl,v
diff -u -r1.10 -r1.11
--- openacs-4/packages/news-aggregator/www/index.tcl	7 Apr 2018 11:09:13 -0000	1.10
+++ openacs-4/packages/news-aggregator/www/index.tcl	7 Apr 2018 16:58:52 -0000	1.11
@@ -85,7 +85,7 @@
 set create_url "${package_url}/aggregator"
 
 set limit [parameter::get -parameter "number_of_items_shown"]
-set sql_limit [expr 7*$limit]
+set sql_limit [expr {7*$limit}]
 
 set top 0
 set bottom 1073741824
@@ -156,16 +156,16 @@
         }
     }
 
-    if { [exists_and_not_null content_encoded] } {
-	if { [exists_and_not_null item_title] } {
+    if { ([info exists content_encoded] && $content_encoded ne "") } {
+	if { ([info exists item_title] && $item_title ne "") } {
 	    set content "<a href=\"$item_link\">$item_title</a>. $content_encoded"
 	} else {
             set content $content_encoded
 	}
     } else {
         set text_only [util_remove_html_tags $item_description]
 
-        if { [exists_and_not_null item_title] } {
+        if { ([info exists item_title] && $item_title ne "") } {
             set content "<a href=\"$item_link\">$item_title</a>. 		    <span class=\"item_author\">$item_author</span>
 $item_description"
         } else {
@@ -179,7 +179,7 @@
         set item_guid_link $item_link
     }
 
-    set diff [news_aggregator::last_scanned -diff [expr [expr [clock seconds] - [clock scan $last_scanned]] / 60]]
+    set diff [news_aggregator::last_scanned -diff [expr [expr {[clock seconds] - [clock scan $last_scanned]}] / 60]]
     set source_url [export_vars -base source {source_id}]
     set technorati_url "http://www.technorati.com/cosmos/links.html?url=$link&sub=Get+Link+Cosmos"
 
@@ -191,7 +191,7 @@
         set pub_date [clock format $localtime -format "%m-%d %H:%M"]
     }
 
-    if { [string equal $write_p "1"] } {
+    if {$write_p eq "1"} {
 	if { [lsearch $saved_items $item_id] == -1 } {
             set save_url [export_vars -base "${url}item-save" {item_id}]
 	    set unsave_url ""
@@ -213,7 +213,7 @@
 }
 
 if { $enable_purge_p &&
-     [exists_and_not_null top] && [exists_and_not_null bottom] &&
+     ([info exists top] && $top ne "") && ([info exists bottom] && $bottom ne "") &&
      $top >= $bottom && $public_p == "f" &&
      [permission::permission_p -party_id $user_id -object_id $aggregator_id -privilege write] } {
     
Index: openacs-4/packages/news-aggregator/www/item-blog.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/news-aggregator/www/item-blog.tcl,v
diff -u -r1.1 -r1.2
--- openacs-4/packages/news-aggregator/www/item-blog.tcl	20 Mar 2004 11:04:39 -0000	1.1
+++ openacs-4/packages/news-aggregator/www/item-blog.tcl	7 Apr 2018 16:58:52 -0000	1.2
@@ -12,12 +12,12 @@
 
 db_1row select_item {}
 
-if { [exists_and_not_null content_encoded] } {
+if { ([info exists content_encoded] && $content_encoded ne "") } {
     set content $content_encoded
 } else {
     set text_only [util_remove_html_tags $item_description]
     
-    if {[exists_and_not_null item_title] && ![string equal -nocase $item_title $text_only] } {
+    if {([info exists item_title] && $item_title ne "") && ![string equal -nocase $item_title $text_only] } {
         set content "<a href=\"$item_link\">$item_title</a>. $item_description"
     } else {
         set content $item_description
@@ -49,7 +49,7 @@
 
     db_1row select_weblog ""
 
-    if { [exists_and_not_null content_encoded] } {
+    if { ([info exists content_encoded] && $content_encoded ne "") } {
         set text $content_encoded
     } else {
         set text $item_description
Index: openacs-4/packages/news-aggregator/www/opml-import-2.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/news-aggregator/www/opml-import-2.tcl,v
diff -u -r1.2 -r1.3
--- openacs-4/packages/news-aggregator/www/opml-import-2.tcl	1 Mar 2005 00:01:39 -0000	1.2
+++ openacs-4/packages/news-aggregator/www/opml-import-2.tcl	7 Apr 2018 16:58:52 -0000	1.3
@@ -34,7 +34,7 @@
 
     array set opml [news_aggregator::opml::parse -xml $f(page)]
 
-    if { $opml(status) == "failure" } {
+    if { $opml(status) eq "failure" } {
 	error "OPML parse error: $opml(errmsg)"
     }
 
Index: openacs-4/packages/news-aggregator/www/settings.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/news-aggregator/www/settings.tcl,v
diff -u -r1.2 -r1.3
--- openacs-4/packages/news-aggregator/www/settings.tcl	20 Jan 2018 23:00:54 -0000	1.2
+++ openacs-4/packages/news-aggregator/www/settings.tcl	7 Apr 2018 16:58:52 -0000	1.3
@@ -83,7 +83,7 @@
     delete_onclick 
     default_p
 } aggregators select_aggregators {} {
-    if { [string equal $public_p t] } {
+    if {$public_p == "t"} {
         set public_p "Yes"
     } else {
         set public_p "No"
@@ -94,7 +94,7 @@
     set delete_url [export_vars -base aggregator-delete {{delete_aggregator_id $aggregator_id}}]
     set delete_onclick "return confirm('Are you sure you want to delete this news aggregator?');"
 
-    if { [string equal $aggregator_id $default_aggregator] } {
+    if {$aggregator_id eq $default_aggregator} {
         set default_p 1
     } else {
         set default_p 0
Index: openacs-4/packages/news-aggregator/www/subscription-copy.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/news-aggregator/www/subscription-copy.tcl,v
diff -u -r1.2 -r1.3
--- openacs-4/packages/news-aggregator/www/subscription-copy.tcl	25 Jan 2005 23:17:09 -0000	1.2
+++ openacs-4/packages/news-aggregator/www/subscription-copy.tcl	7 Apr 2018 16:58:52 -0000	1.3
@@ -18,7 +18,7 @@
 set package_id [ad_conn package_id]
 set package_url [ad_conn package_url]
 
-if { [exists_and_not_null copy_to] } {
+if { ([info exists copy_to] && $copy_to ne "") } {
 
     foreach source_id $source_ids {
         news_aggregator::subscription::copy \
@@ -32,7 +32,7 @@
 
 set aggregator_count [db_string count_aggregators {}]
 
-if { [string equal $aggregator_count "2"] } {
+if {$aggregator_count eq "2"} {
     set copy_to [db_string select_aggregator_id {}]
 
     foreach source $source_id {
Index: openacs-4/packages/news-aggregator/www/subscription-move.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/news-aggregator/www/subscription-move.tcl,v
diff -u -r1.1 -r1.2
--- openacs-4/packages/news-aggregator/www/subscription-move.tcl	20 Mar 2004 11:04:39 -0000	1.1
+++ openacs-4/packages/news-aggregator/www/subscription-move.tcl	7 Apr 2018 16:58:52 -0000	1.2
@@ -18,7 +18,7 @@
 set package_id [ad_conn package_id]
 set package_url [ad_conn package_url]
 
-if { [exists_and_not_null move_to] } {
+if { ([info exists move_to] && $move_to ne "") } {
 
     foreach source_id $source_ids {
         news_aggregator::subscription::move \
@@ -33,7 +33,7 @@
 
 set aggregator_count [db_string count_aggregators {}]
 
-if { [string equal $aggregator_count "2"] } {
+if {$aggregator_count eq "2"} {
     set move_to [db_string select_aggregator_id {}]
 
     foreach source $source_id {
Index: openacs-4/packages/news-aggregator/www/subscriptions.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/news-aggregator/www/subscriptions.tcl,v
diff -u -r1.8 -r1.9
--- openacs-4/packages/news-aggregator/www/subscriptions.tcl	7 Apr 2018 11:09:13 -0000	1.8
+++ openacs-4/packages/news-aggregator/www/subscriptions.tcl	7 Apr 2018 16:58:52 -0000	1.9
@@ -26,7 +26,7 @@
 
 # This is done in case we want to implement some user interface
 # stuff in the future where it might be useful.
-if { [empty_string_p $feed_url] } {
+if { $feed_url eq "" } {
     set feed_url_val ""
 } else {
     set feed_url_val $feed_url
@@ -35,7 +35,7 @@
     #ad_returnredirect "[ad_conn package_url]opml/$aggregator_id/mySubscriptions.opml"
     #ad_script_abort
 
-if { [exists_and_not_null source_id] } {
+if { ([info exists source_id] && $source_id ne "") } {
     set delete_count 0
     foreach delete_id $source_id {
         news_aggregator::subscription::delete \
@@ -144,7 +144,7 @@
     }
 } -validate {
     {feed_url
-	{ [exists_and_not_null feed_url] && ![string equal "http://" $feed_url] } 
+	{ ([info exists feed_url] && $feed_url ne "") && "http://" ne $feed_url } 
         { You must specify a URL }
     }
 } -new_data {