replace NULL with null

Another global search-and-replace update. Here, I've replaced the PHP
keyword 'NULL' with its lowercase version. This is another PEAR code
standards change.

darcs-hash:20081223192129-84dde-4a0182e0ec16a01ad88745ad3e08f7cb501aee0b.gz

52 files changed, 216 insertions, 216 deletions

diff --git a/actions/allrss.php b/actions/allrss.php
index d28fcea49..851cd0ad5 100644
--- a/actions/allrss.php
+++ b/actions/allrss.php
@@ -25,7 +25,7 @@ require_once(INSTALLDIR.'/lib/rssaction.php');
 
 class AllrssAction extends Rss10Action {
 
-    var $user = NULL;
+    var $user = null;
 
     function init() {
         $nickname = $this->trimmed('nickname');
@@ -69,9 +69,9 @@ class AllrssAction extends Rss10Action {
         $user = $this->user;
         $profile = $user->getProfile();
         if (!$profile) {
-            return NULL;
+            return null;
         }
         $avatar = $profile->getAvatar(AVATAR_PROFILE_SIZE);
-        return ($avatar) ? $avatar->url : NULL;
+        return ($avatar) ? $avatar->url : null;
     }
 }
\ No newline at end of file
diff --git a/actions/api.php b/actions/api.php
index e03961e21..e7646a7bb 100644
--- a/actions/api.php
+++ b/actions/api.php
@@ -152,8 +152,8 @@ class ApiAction extends Action {
             header('Content-Type: application/xml; charset=utf-8');
             common_start_xml();
             common_element_start('hash');
-            common_element('error', NULL, $msg);
-            common_element('request', NULL, $_SERVER['REQUEST_URI']);
+            common_element('error', null, $msg);
+            common_element('request', null, $_SERVER['REQUEST_URI']);
             common_element_end('hash');
             common_end_xml();
         } else if ($this->content_type == 'json')  {
diff --git a/actions/block.php b/actions/block.php
index 20ba81edb..cfcd29848 100644
--- a/actions/block.php
+++ b/actions/block.php
@@ -21,7 +21,7 @@ if (!defined('LACONICA')) { exit(1); }
 
 class BlockAction extends Action {
 
-    var $profile = NULL;
+    var $profile = null;
 
     function prepare($args) {
 
@@ -77,7 +77,7 @@ class BlockAction extends Action {
 
         common_show_header(_('Block user'));
 
-        common_element('p', NULL,
+        common_element('p', null,
                        _('Are you sure you want to block this user? '.
                          'Afterwards, they will be unsubscribed from you, '.
                          'unable to subscribe to you in the future, and '.
diff --git a/actions/confirmaddress.php b/actions/confirmaddress.php
index 9d97c8205..562b70fe9 100644
--- a/actions/confirmaddress.php
+++ b/actions/confirmaddress.php
@@ -88,7 +88,7 @@ class ConfirmaddressAction extends Action {
         $cur->query('COMMIT');
 
         common_show_header(_('Confirm Address'));
-        common_element('p', NULL,
+        common_element('p', null,
                        sprintf(_('The address "%s" has been confirmed for your account.'), $cur->$type));
         common_show_footer();
     }
diff --git a/actions/deletenotice.php b/actions/deletenotice.php
index ba348c5fa..0777918d2 100644
--- a/actions/deletenotice.php
+++ b/actions/deletenotice.php
@@ -41,7 +41,7 @@ class DeletenoticeAction extends DeleteAction {
         return _('Delete notice');
     }
 
-    function show_form($error=NULL) {
+    function show_form($error=null) {
         $user = common_current_user();
 
         common_show_header($this->get_title(), array($this, 'show_header'), $error,
@@ -91,7 +91,7 @@ class DeletenoticeAction extends DeleteAction {
             $notice->delete();
         } else {
             if ($url) {
-                common_set_returnto(NULL);
+                common_set_returnto(null);
             } else {
                 $url = common_local_url('public');
             }
diff --git a/actions/deleteprofile.php b/actions/deleteprofile.php
index 29797bc76..503b3666d 100644
--- a/actions/deleteprofile.php
+++ b/actions/deleteprofile.php
@@ -36,9 +36,9 @@ class DeleteprofileAction extends Action {
         return _('Export and delete your user information.');
     }
 
-    function form_header($title, $msg=NULL, $success=false) {
+    function form_header($title, $msg=null, $success=false) {
         common_show_header($title,
-                           NULL,
+                           null,
                            array($msg, $success),
                            array($this, 'show_top'));
     }
@@ -84,9 +84,9 @@ class DeleteprofileAction extends Action {
         common_element_end('li');
     }
 
-    function show_form($msg=NULL, $success=false) {
+    function show_form($msg=null, $success=false) {
         $this->form_header(_('Delete my account'), $msg, $success);
-        common_element('h2', NULL, _('Delete my account confirmation'));
+        common_element('h2', null, _('Delete my account confirmation'));
         $this->show_confirm_delete_form();
         common_show_footer();
     }
@@ -213,7 +213,7 @@ class DeleteprofileAction extends Action {
         $n_users_deleted = $user->delete();
 
         // logout and redirect to public
-        common_set_user(NULL);
+        common_set_user(null);
         common_real_login(false); # not logged in
         common_forgetme(); # don't log back in!
         common_redirect(common_local_url('public'));
diff --git a/actions/emailsettings.php b/actions/emailsettings.php
index b77817c8e..06b3ef29f 100644
--- a/actions/emailsettings.php
+++ b/actions/emailsettings.php
@@ -27,7 +27,7 @@ class EmailsettingsAction extends SettingsAction {
         return _('Manage how you get email from %%site.name%%.');
     }
 
-    function show_form($msg=NULL, $success=false) {
+    function show_form($msg=null, $success=false) {
         $user = common_current_user();
         $this->form_header(_('Email Settings'), $msg, $success);
         common_element_start('form', array('method' => 'post',
@@ -36,7 +36,7 @@ class EmailsettingsAction extends SettingsAction {
                                            common_local_url('emailsettings')));
         common_hidden('token', common_session_token());
 
-        common_element('h2', NULL, _('Address'));
+        common_element('h2', null, _('Address'));
 
         if ($user->email) {
             common_element_start('p');
@@ -58,14 +58,14 @@ class EmailsettingsAction extends SettingsAction {
                 common_submit('cancel', _('Cancel'));
             } else {
                 common_input('email', _('Email Address'),
-                             ($this->arg('email')) ? $this->arg('email') : NULL,
+                             ($this->arg('email')) ? $this->arg('email') : null,
                              _('Email address, like "UserName@example.org"'));
                 common_submit('add', _('Add'));
             }
         }
 
         if ($user->email) {
-            common_element('h2', NULL, _('Incoming email'));
+            common_element('h2', null, _('Incoming email'));
             
             if ($user->incomingemail) {
                 common_element_start('p');
@@ -83,7 +83,7 @@ class EmailsettingsAction extends SettingsAction {
             common_submit('newincoming', _('New'));
         }
         
-        common_element('h2', NULL, _('Preferences'));
+        common_element('h2', null, _('Preferences'));
 
         common_checkbox('emailnotifysub',
                         _('Send me notices of new subscriptions through email.'),
@@ -118,7 +118,7 @@ class EmailsettingsAction extends SettingsAction {
         if ($confirm->find(TRUE)) {
             return $confirm;
         } else {
-            return NULL;
+            return null;
         }
     }
 
@@ -273,7 +273,7 @@ class EmailsettingsAction extends SettingsAction {
 
         $user->query('BEGIN');
         $original = clone($user);
-        $user->email = NULL;
+        $user->email = null;
         $result = $user->updateKeys($original);
         if (!$result) {
             common_log_db_error($user, 'UPDATE', __FILE__);
@@ -294,7 +294,7 @@ class EmailsettingsAction extends SettingsAction {
         }
         
         $orig = clone($user);
-        $user->incomingemail = NULL;
+        $user->incomingemail = null;
 
         if (!$user->updateKeys($orig)) {
             common_log_db_error($user, 'UPDATE', __FILE__);
diff --git a/actions/favorited.php b/actions/favorited.php
index 6a465df96..e69630d50 100644
--- a/actions/favorited.php
+++ b/actions/favorited.php
@@ -29,7 +29,7 @@ class FavoritedAction extends StreamAction {
         $page = ($this->arg('page')) ? ($this->arg('page')+0) : 1;
 
         common_show_header(_('Popular notices'),
-                           array($this, 'show_header'), NULL,
+                           array($this, 'show_header'), null,
                            array($this, 'show_top'));
 
         $this->show_notices($page);
diff --git a/actions/favoritesrss.php b/actions/favoritesrss.php
index 642d4f880..7071812d7 100644
--- a/actions/favoritesrss.php
+++ b/actions/favoritesrss.php
@@ -25,7 +25,7 @@ require_once(INSTALLDIR.'/lib/rssaction.php');
 
 class FavoritesrssAction extends Rss10Action {
 
-    var $user = NULL;
+    var $user = null;
     
     function init() {
         $nickname = $this->trimmed('nickname');
@@ -68,6 +68,6 @@ class FavoritesrssAction extends Rss10Action {
     }
 
     function get_image() {
-        return NULL;
+        return null;
     }
 }
\ No newline at end of file
diff --git a/actions/featured.php b/actions/featured.php
index 2ff4f7745..f478a4017 100644
--- a/actions/featured.php
+++ b/actions/featured.php
@@ -30,7 +30,7 @@ class FeaturedAction extends StreamAction {
         $page = ($this->arg('page')) ? ($this->arg('page')+0) : 1;
 
         common_show_header(_('Featured users'),
-                           array($this, 'show_header'), NULL,
+                           array($this, 'show_header'), null,
                            array($this, 'show_top'));
 
         $this->show_notices($page);
diff --git a/actions/finishaddopenid.php b/actions/finishaddopenid.php
index 07024e091..7607688de 100644
--- a/actions/finishaddopenid.php
+++ b/actions/finishaddopenid.php
@@ -97,7 +97,7 @@ class FinishaddopenidAction extends Action {
 
     function message($msg) {
         common_show_header(_('OpenID Login'));
-        common_element('p', NULL, $msg);
+        common_element('p', null, $msg);
         common_show_footer();
     }
 }
diff --git a/actions/finishopenidlogin.php b/actions/finishopenidlogin.php
index a2a778f31..ae5b136a2 100644
--- a/actions/finishopenidlogin.php
+++ b/actions/finishopenidlogin.php
@@ -52,7 +52,7 @@ class FinishopenidloginAction extends Action {
         }
     }
 
-    function show_top($error=NULL) {
+    function show_top($error=null) {
         if ($error) {
             common_element('div', array('class' => 'error'), $error);
         } else {
@@ -62,17 +62,17 @@ class FinishopenidloginAction extends Action {
         }
     }
 
-    function show_form($error=NULL, $username=NULL) {
-        common_show_header(_('OpenID Account Setup'), NULL, $error,
+    function show_form($error=null, $username=null) {
+        common_show_header(_('OpenID Account Setup'), null, $error,
                            array($this, 'show_top'));
 
         common_element_start('form', array('method' => 'post',
                                            'id' => 'account_connect',
                                            'action' => common_local_url('finishopenidlogin')));
         common_hidden('token', common_session_token());
-        common_element('h2', NULL,
+        common_element('h2', null,
                        _('Create new account'));
-        common_element('p', NULL,
+        common_element('p', null,
                        _('Create a new user with this nickname.'));
         common_input('newname', _('New nickname'),
                      ($username) ? $username : '',
@@ -88,9 +88,9 @@ class FinishopenidloginAction extends Action {
         common_text(_(' except this private data: password, email address, IM address, phone number.'));
         common_element_end('p');
         common_submit('create', _('Create'));
-        common_element('h2', NULL,
+        common_element('h2', null,
                        _('Connect existing account'));
-        common_element('p', NULL,
+        common_element('p', null,
                        _('If you already have an account, login with your username and password to connect it to your OpenID.'));
         common_input('nickname', _('Existing nickname'));
         common_password('password', _('Password'));
@@ -141,14 +141,14 @@ class FinishopenidloginAction extends Action {
                 $this->go_home($user->nickname);
             } else {
                 $this->save_values($display, $canonical, $sreg);
-                $this->show_form(NULL, $this->best_new_nickname($display, $sreg));
+                $this->show_form(null, $this->best_new_nickname($display, $sreg));
             }
         }
     }
 
     function message($msg) {
         common_show_header(_('OpenID Login'));
-        common_element('p', NULL, $msg);
+        common_element('p', null, $msg);
         common_show_footer();
     }
 
@@ -290,7 +290,7 @@ class FinishopenidloginAction extends Action {
         $url = common_get_returnto();
         if ($url) {
             # We don't have to return to it again
-            common_set_returnto(NULL);
+            common_set_returnto(null);
         } else {
             $url = common_local_url('all',
                                     array('nickname' =>
@@ -329,7 +329,7 @@ class FinishopenidloginAction extends Action {
 
         # XXX: others?
 
-        return NULL;
+        return null;
     }
 
     function is_new_nickname($str) {
@@ -369,7 +369,7 @@ class FinishopenidloginAction extends Action {
 
         foreach ($bad as $badpart) {
             if (array_key_exists($badpart, $parts)) {
-                return NULL;
+                return null;
             }
         }
 
@@ -403,14 +403,14 @@ class FinishopenidloginAction extends Action {
             }
         }
 
-        return NULL;
+        return null;
     }
 
     function xri_to_nickname($xri) {
         $base = $this->xri_base($xri);
 
         if (!$base) {
-            return NULL;
+            return null;
         } else {
             # =evan.prodromou
             # or @gratis*evan.prodromou
diff --git a/actions/finishremotesubscribe.php b/actions/finishremotesubscribe.php
index c3387cf02..edd4ae541 100644
--- a/actions/finishremotesubscribe.php
+++ b/actions/finishremotesubscribe.php
@@ -278,7 +278,7 @@ class FinishremotesubscribeAction extends Action {
         common_debug('got result: "'.print_r($result,TRUE).'"', __FILE__);
 
         if ($result->status != 200) {
-            return NULL;
+            return null;
         }
 
         parse_str($result->body, $return);
diff --git a/actions/foaf.php b/actions/foaf.php
index 310ba2c19..218e20f5f 100644
--- a/actions/foaf.php
+++ b/actions/foaf.php
@@ -66,21 +66,21 @@ class FoafAction extends Action {
         # XXX: might not be a person
         common_element_start('Person', array('rdf:about' =>
                                              $user->uri));
-        common_element('mbox_sha1sum', NULL, sha1('mailto:' . $user->email));
+        common_element('mbox_sha1sum', null, sha1('mailto:' . $user->email));
         if ($profile->fullname) {
-            common_element('name', NULL, $profile->fullname);
+            common_element('name', null, $profile->fullname);
         }
         if ($profile->homepage) {
             common_element('homepage', array('rdf:resource' => $profile->homepage));
         }
         if ($profile->bio) {
-            common_element('rdfs:comment', NULL, $profile->bio);
+            common_element('rdfs:comment', null, $profile->bio);
         }
         # XXX: more structured location data
         if ($profile->location) {
             common_element_start('based_near');
             common_element_start('geo:SpatialThing');
-            common_element('name', NULL, $profile->location);
+            common_element('name', null, $profile->location);
             common_element_end('geo:SpatialThing');
             common_element_end('based_near');
         }
@@ -156,7 +156,7 @@ class FoafAction extends Action {
         common_element_end('Person');
 
         foreach ($person as $uri => $p) {
-            $foaf_url = NULL;
+            $foaf_url = null;
             if ($p[1] instanceof User) {
                 $foaf_url = common_local_url('foaf', array('nickname' => $p[1]->nickname));
             }
@@ -166,7 +166,7 @@ class FoafAction extends Action {
                 common_element('knows', array('rdf:resource' => $user->uri));
             }
             $this->show_microblogging_account($profile, ($p[1] instanceof User) ?
-                                              common_root_url() : NULL);
+                                              common_root_url() : null);
             if ($foaf_url) {
                 common_element('rdfs:seeAlso', array('rdf:resource' => $foaf_url));
             }
@@ -186,7 +186,7 @@ class FoafAction extends Action {
         common_element_end('PersonalProfileDocument');
     }
 
-    function show_microblogging_account($profile, $service=NULL) {
+    function show_microblogging_account($profile, $service=null) {
         # Their account
         common_element_start('holdsAccount');
         common_element_start('OnlineAccount');
@@ -194,7 +194,7 @@ class FoafAction extends Action {
             common_element('accountServiceHomepage', array('rdf:resource' =>
                                                            $service));
         }
-        common_element('accountName', NULL, $profile->nickname);
+        common_element('accountName', null, $profile->nickname);
         common_element('homepage', array('rdf:resource' => $profile->profileurl));
         common_element_end('OnlineAccount');
         common_element_end('holdsAccount');
diff --git a/actions/imsettings.php b/actions/imsettings.php
index d0c47f7fd..8f546f8e7 100644
--- a/actions/imsettings.php
+++ b/actions/imsettings.php
@@ -28,7 +28,7 @@ class ImsettingsAction extends SettingsAction {
         return _('You can send and receive notices through Jabber/GTalk [instant messages](%%doc.im%%). Configure your address and settings below.');
     }
 
-    function show_form($msg=NULL, $success=false) {
+    function show_form($msg=null, $success=false) {
         $user = common_current_user();
         $this->form_header(_('IM Settings'), $msg, $success);
         common_element_start('form', array('method' => 'post',
@@ -37,7 +37,7 @@ class ImsettingsAction extends SettingsAction {
                                            common_local_url('imsettings')));
         common_hidden('token', common_session_token());
 
-        common_element('h2', NULL, _('Address'));
+        common_element('h2', null, _('Address'));
 
         if ($user->jabber) {
             common_element_start('p');
@@ -59,13 +59,13 @@ class ImsettingsAction extends SettingsAction {
                 common_submit('cancel', _('Cancel'));
             } else {
                 common_input('jabber', _('IM Address'),
-                             ($this->arg('jabber')) ? $this->arg('jabber') : NULL,
+                             ($this->arg('jabber')) ? $this->arg('jabber') : null,
                          sprintf(_('Jabber or GTalk address, like "UserName@example.org". First, make sure to add %s to your buddy list in your IM client or on GTalk.'), jabber_daemon_address()));
                 common_submit('add', _('Add'));
             }
         }
 
-        common_element('h2', NULL, _('Preferences'));
+        common_element('h2', null, _('Preferences'));
 
         common_checkbox('jabbernotify',
                         _('Send me notices through Jabber/GTalk.'),
@@ -93,7 +93,7 @@ class ImsettingsAction extends SettingsAction {
         if ($confirm->find(TRUE)) {
             return $confirm;
         } else {
-            return NULL;
+            return null;
         }
     }
 
@@ -244,7 +244,7 @@ class ImsettingsAction extends SettingsAction {
 
         $user->query('BEGIN');
         $original = clone($user);
-        $user->jabber = NULL;
+        $user->jabber = null;
         $result = $user->updateKeys($original);
         if (!$result) {
             common_log_db_error($user, 'UPDATE', __FILE__);
diff --git a/actions/invite.php b/actions/invite.php
index e5cc6ad01..feef94d0f 100644
--- a/actions/invite.php
+++ b/actions/invite.php
@@ -85,49 +85,49 @@ class InviteAction extends Action {
 
         common_show_header(_('Invitation(s) sent'));
         if ($already) {
-            common_element('p', NULL, _('You are already subscribed to these users:'));
+            common_element('p', null, _('You are already subscribed to these users:'));
             common_element_start('ul');
             foreach ($already as $other) {
-                common_element('li', NULL, sprintf(_('%s (%s)'), $other->nickname, $other->email));
+                common_element('li', null, sprintf(_('%s (%s)'), $other->nickname, $other->email));
             }
             common_element_end('ul');
         }
         if ($subbed) {
-            common_element('p', NULL, _('These people are already users and you were automatically subscribed to them:'));
+            common_element('p', null, _('These people are already users and you were automatically subscribed to them:'));
             common_element_start('ul');
             foreach ($subbed as $other) {
-                common_element('li', NULL, sprintf(_('%s (%s)'), $other->nickname, $other->email));
+                common_element('li', null, sprintf(_('%s (%s)'), $other->nickname, $other->email));
             }
             common_element_end('ul');
         }
         if ($sent) {
-            common_element('p', NULL, _('Invitation(s) sent to the following people:'));
+            common_element('p', null, _('Invitation(s) sent to the following people:'));
             common_element_start('ul');
             foreach ($sent as $other) {
-                common_element('li', NULL, $other);
+                common_element('li', null, $other);
             }
             common_element_end('ul');
-            common_element('p', NULL, _('You will be notified when your invitees accept the invitation and register on the site. Thanks for growing the community!'));
+            common_element('p', null, _('You will be notified when your invitees accept the invitation and register on the site. Thanks for growing the community!'));
         }
         common_show_footer();
     }
 
-    function show_top($error=NULL) {
+    function show_top($error=null) {
         if ($error) {
             common_element('p', 'error', $error);
         } else {
             common_element_start('div', 'instructions');
-            common_element('p', NULL,
+            common_element('p', null,
                            _('Use this form to invite your friends and colleagues to use this service.'));
             common_element_end('div');
         }
     }
 
-    function show_form($error=NULL) {
+    function show_form($error=null) {
 
         global $config;
 
-        common_show_header(_('Invite new users'), NULL, $error, array($this, 'show_top'));
+        common_show_header(_('Invite new users'), null, $error, array($this, 'show_top'));
 
         common_element_start('form', array('method' => 'post',
                                            'id' => 'invite',
diff --git a/actions/login.php b/actions/login.php
index 5e4d45149..f3509519e 100644
--- a/actions/login.php
+++ b/actions/login.php
@@ -63,7 +63,7 @@ class LoginAction extends Action {
             $url = common_get_returnto();
             if ($url) {
                 # We don't have to return to it again
-                common_set_returnto(NULL);
+                common_set_returnto(null);
             } else {
                 $url = common_local_url('all',
                                         array('nickname' =>
@@ -91,7 +91,7 @@ class LoginAction extends Action {
         $url = common_get_returnto();
         if ($url) {
             # We don't have to return to it again
-            common_set_returnto(NULL);
+            common_set_returnto(null);
         } else {
             $url = common_local_url('all',
                                     array('nickname' =>
@@ -100,8 +100,8 @@ class LoginAction extends Action {
         common_redirect($url);
     }
 
-    function show_form($error=NULL) {
-        common_show_header(_('Login'), NULL, $error, array($this, 'show_top'));
+    function show_form($error=null) {
+        common_show_header(_('Login'), null, $error, array($this, 'show_top'));
         common_element_start('form', array('method' => 'post',
                                            'id' => 'login',
                                            'action' => common_local_url('login')));
@@ -138,7 +138,7 @@ class LoginAction extends Action {
         }
     }
 
-    function show_top($error=NULL) {
+    function show_top($error=null) {
         if ($error) {
             common_element('p', 'error', $error);
         } else {
diff --git a/actions/logout.php b/actions/logout.php
index 5f7b9d502..4c59e47ad 100644
--- a/actions/logout.php
+++ b/actions/logout.php
@@ -32,7 +32,7 @@ class LogoutAction extends Action {
         if (!common_logged_in()) {
             common_user_error(_('Not logged in.'));
         } else {
-            common_set_user(NULL);
+            common_set_user(null);
             common_real_login(false); # not logged in
             common_forgetme(); # don't log back in!
             common_redirect(common_local_url('public'));
diff --git a/actions/newmessage.php b/actions/newmessage.php
index 121fc4246..eb582c2a5 100644
--- a/actions/newmessage.php
+++ b/actions/newmessage.php
@@ -98,7 +98,7 @@ class NewmessageAction extends Action {
         common_message_form($content, $user, $to);
     }
 
-    function show_form($msg=NULL) {
+    function show_form($msg=null) {
         
         $content = $this->trimmed('content');
         $user = common_current_user();
@@ -117,7 +117,7 @@ class NewmessageAction extends Action {
             return;
         }
         
-        common_show_header(_('New message'), NULL,
+        common_show_header(_('New message'), null,
                            array($content, $user, $other),
                            array($this, 'show_top'));
         
diff --git a/actions/newnotice.php b/actions/newnotice.php
index 7c3ad8815..98556c36b 100644
--- a/actions/newnotice.php
+++ b/actions/newnotice.php
@@ -78,7 +78,7 @@ class NewnoticeAction extends Action {
 
         $replyto = $this->trimmed('inreplyto');
 
-        $notice = Notice::saveNew($user->id, $content, 'web', 1, ($replyto == 'false') ? NULL : $replyto);
+        $notice = Notice::saveNew($user->id, $content, 'web', 1, ($replyto == 'false') ? null : $replyto);
 
         if (is_string($notice)) {
             $this->show_form($notice);
@@ -121,11 +121,11 @@ class NewnoticeAction extends Action {
         common_element_end('html');
     }
 
-    function show_top($content=NULL) {
-        common_notice_form(NULL, $content);
+    function show_top($content=null) {
+        common_notice_form(null, $content);
     }
 
-    function show_form($msg=NULL) {
+    function show_form($msg=null) {
         if ($msg && $this->boolean('ajax')) {
             $this->ajax_error_msg($msg);
             return;
@@ -138,7 +138,7 @@ class NewnoticeAction extends Action {
                 $content = '@' . $profile->nickname . ' ';
             }
         }
-        common_show_header(_('New notice'), NULL, $content,
+        common_show_header(_('New notice'), null, $content,
                            array($this, 'show_top'));
         if ($msg) {
             common_element('p', array('id' => 'error'), $msg);
diff --git a/actions/noticesearchrss.php b/actions/noticesearchrss.php
index a7df62ca0..d61234df8 100644
--- a/actions/noticesearchrss.php
+++ b/actions/noticesearchrss.php
@@ -65,6 +65,6 @@ class NoticesearchrssAction extends Rss10Action {
     }
 
     function get_image() {
-        return NULL;
+        return null;
     }
 }
diff --git a/actions/openidlogin.php b/actions/openidlogin.php
index 6192dfc34..1bf37f28f 100644
--- a/actions/openidlogin.php
+++ b/actions/openidlogin.php
@@ -52,7 +52,7 @@ class OpenidloginAction extends Action {
             }
         } else {
             $openid_url = oid_get_last();
-            $this->show_form(NULL, $openid_url);
+            $this->show_form(null, $openid_url);
         }
     }
 
@@ -60,7 +60,7 @@ class OpenidloginAction extends Action {
         return _('Login with an [OpenID](%%doc.openid%%) account.');
     }
 
-    function show_top($error=NULL) {
+    function show_top($error=null) {
         if ($error) {
             common_element('div', array('class' => 'error'), $error);
         } else {
@@ -72,8 +72,8 @@ class OpenidloginAction extends Action {
         }
     }
 
-    function show_form($error=NULL, $openid_url) {
-        common_show_header(_('OpenID Login'), NULL, $error, array($this, 'show_top'));
+    function show_form($error=null, $openid_url) {
+        common_show_header(_('OpenID Login'), null, $error, array($this, 'show_top'));
         $formaction = common_local_url('openidlogin');
         common_element_start('form', array('method' => 'post',
                                            'id' => 'openidlogin',
diff --git a/actions/openidsettings.php b/actions/openidsettings.php
index dd575bb73..9c0eda6f0 100644
--- a/actions/openidsettings.php
+++ b/actions/openidsettings.php
@@ -30,7 +30,7 @@ class OpenidsettingsAction extends SettingsAction {
                   ' Manage your associated OpenIDs from here.');
     }
 
-    function show_form($msg=NULL, $success=false) {
+    function show_form($msg=null, $success=false) {
 
         $user = common_current_user();
 
@@ -41,8 +41,8 @@ class OpenidsettingsAction extends SettingsAction {
                                            'action' =>
                                            common_local_url('openidsettings')));
         common_hidden('token', common_session_token());
-        common_element('h2', NULL, _('Add OpenID'));
-        common_element('p', NULL,
+        common_element('h2', null, _('Add OpenID'));
+        common_element('p', null,
                        _('If you want to add an OpenID to your account, ' .
                           'enter it in the box below and click "Add".'));
         common_element_start('p');
@@ -66,11 +66,11 @@ class OpenidsettingsAction extends SettingsAction {
 
         if ($cnt > 0) {
 
-            common_element('h2', NULL, _('Remove OpenID'));
+            common_element('h2', null, _('Remove OpenID'));
 
             if ($cnt == 1 && !$user->password) {
 
-                common_element('p', NULL,
+                common_element('p', null,
                                _('Removing your only OpenID would make it impossible to log in! ' .
                                   'If you need to remove it, add another OpenID first.'));
 
@@ -83,7 +83,7 @@ class OpenidsettingsAction extends SettingsAction {
 
             } else {
 
-                common_element('p', NULL,
+                common_element('p', null,
                                _('You can remove an OpenID from your account '.
                                   'by clicking the button marked "Remove".'));
                 $idx = 0;
diff --git a/actions/opensearch.php b/actions/opensearch.php
index 707e929fb..dcde160a4 100644
--- a/actions/opensearch.php
+++ b/actions/opensearch.php
@@ -42,16 +42,16 @@ class OpensearchAction extends Action {
         common_element_start('OpenSearchDescription', array('xmlns' => 'http://a9.com/-/spec/opensearch/1.1/'));
 
         $short_name =  common_config('site', 'name').' '.$short_name;
-        common_element('ShortName', NULL, $short_name);
-        common_element('Contact', NULL, common_config('site', 'email'));
+        common_element('ShortName', null, $short_name);
+        common_element('Contact', null, common_config('site', 'email'));
         common_element('Url', array('type' => 'text/html', 'method' => 'get',
                        'template' => str_replace('---', '{searchTerms}', common_local_url($type, array('q' => '---')))));
         common_element('Image', array('height' => 16, 'width' => 16, 'type' => 'image/vnd.microsoft.icon'), common_path('favicon.ico'));
         common_element('Image', array('height' => 50, 'width' => 50, 'type' => 'image/png'), theme_path('logo.png'));
-        common_element('AdultContent', NULL, 'false');
-        common_element('Language', NULL, common_language());
-        common_element('OutputEncoding', NULL, 'UTF-8');
-        common_element('InputEncoding', NULL, 'UTF-8');
+        common_element('AdultContent', null, 'false');
+        common_element('Language', null, common_language());
+        common_element('OutputEncoding', null, 'UTF-8');
+        common_element('InputEncoding', null, 'UTF-8');
 
         common_element_end('OpenSearchDescription');
         common_end_xml();
diff --git a/actions/othersettings.php b/actions/othersettings.php
index 9b824cea2..1da6577cb 100644
--- a/actions/othersettings.php
+++ b/actions/othersettings.php
@@ -27,12 +27,12 @@ class OthersettingsAction extends SettingsAction {
         return _('Manage various other options.');
     }
 
-    function show_form($msg=NULL, $success=false) {
+    function show_form($msg=null, $success=false) {
         $user = common_current_user();
 
         $this->form_header(_('Other Settings'), $msg, $success);
 
-        common_element('h2', NULL, _('URL Auto-shortening'));
+        common_element('h2', null, _('URL Auto-shortening'));
         common_element_start('form', array('method' => 'post',
                                            'id' => 'othersettings',
                                            'action' =>
@@ -57,7 +57,7 @@ class OthersettingsAction extends SettingsAction {
 
         common_element_end('form');
 
-//        common_element('h2', NULL, _('Delete my account'));
+//        common_element('h2', null, _('Delete my account'));
 //        $this->show_delete_form();
 
         common_show_footer();
diff --git a/actions/peoplesearch.php b/actions/peoplesearch.php
index f89de53f7..a52ac317f 100644
--- a/actions/peoplesearch.php
+++ b/actions/peoplesearch.php
@@ -68,8 +68,8 @@ class PeoplesearchAction extends SearchAction {
 
 class PeopleSearchResults extends ProfileList {
 
-    var $terms = NULL;
-    var $pattern = NULL;
+    var $terms = null;
+    var $pattern = null;
     
     function __construct($profile, $terms) {
         parent::__construct($profile);
diff --git a/actions/peopletag.php b/actions/peopletag.php
index f03a3c8af..0327ecbc2 100644
--- a/actions/peopletag.php
+++ b/actions/peopletag.php
@@ -43,7 +43,7 @@ class PeopletagAction extends Action {
         # Looks like we're good; show the header
 
         common_show_header(sprintf(_('Users self-tagged with %s - page %d'), $tag, $page),
-                           NULL, $tag, array($this, 'show_top'));
+                           null, $tag, array($this, 'show_top'));
 
         $this->show_people($tag, $page);
 
@@ -94,7 +94,7 @@ class PeopletagAction extends Action {
     }
 
     function get_title() {
-        return NULL;
+        return null;
     }
 
     function show_header($arr) {
diff --git a/actions/profilesettings.php b/actions/profilesettings.php
index 3d92161ab..0fa1288dc 100644
--- a/actions/profilesettings.php
+++ b/actions/profilesettings.php
@@ -28,14 +28,14 @@ class ProfilesettingsAction extends SettingsAction {
                   'so people know more about you.');
     }
 
-    function show_form($msg=NULL, $success=false) {
+    function show_form($msg=null, $success=false) {
         $this->form_header(_('Profile settings'), $msg, $success);
         $this->show_settings_form();
-        common_element('h2', NULL, _('Avatar'));
+        common_element('h2', null, _('Avatar'));
         $this->show_avatar_form();
-        common_element('h2', NULL, _('Change password'));
+        common_element('h2', null, _('Change password'));
         $this->show_password_form();
-//        common_element('h2', NULL, _('Delete my account'));
+//        common_element('h2', null, _('Delete my account'));
 //        $this->show_delete_form();
         common_show_footer();
     }
diff --git a/actions/public.php b/actions/public.php
index 422e4bc98..60238e54d 100644
--- a/actions/public.php
+++ b/actions/public.php
@@ -31,7 +31,7 @@ class PublicAction extends StreamAction {
         header('X-XRDS-Location: '. common_local_url('publicxrds'));
 
         common_show_header(_('Public timeline'),
-                           array($this, 'show_header'), NULL,
+                           array($this, 'show_header'), null,
                            array($this, 'show_top'));
 
         # XXX: Public sidebar here?
diff --git a/actions/publicrss.php b/actions/publicrss.php
index fa86de1d9..764f0fae2 100644
--- a/actions/publicrss.php
+++ b/actions/publicrss.php
@@ -52,6 +52,6 @@ class PublicrssAction extends Rss10Action {
     }
 
     function get_image() {
-        return NULL;
+        return null;
     }
 }
\ No newline at end of file
diff --git a/actions/publicxrds.php b/actions/publicxrds.php
index ffd65c8c9..5e3349185 100644
--- a/actions/publicxrds.php
+++ b/actions/publicxrds.php
@@ -42,7 +42,7 @@ class PublicxrdsAction extends Action {
                                           'xmlns:simple' => 'http://xrds-simple.net/core/1.0',
                                           'version' => '2.0'));
 
-        common_element('Type', NULL, 'xri://$xrds*simple');
+        common_element('Type', null, 'xri://$xrds*simple');
 
         foreach (array('finishopenidlogin', 'finishaddopenid', 'finishimmediate') as $finish) {
             $this->show_service(Auth_OpenID_RP_RETURN_TO_URL_TYPE,
@@ -55,24 +55,24 @@ class PublicxrdsAction extends Action {
         common_end_xml();
     }
 
-    function show_service($type, $uri, $params=NULL, $sigs=NULL, $localId=NULL) {
+    function show_service($type, $uri, $params=null, $sigs=null, $localId=null) {
         common_element_start('Service');
         if ($uri) {
-            common_element('URI', NULL, $uri);
+            common_element('URI', null, $uri);
         }
-        common_element('Type', NULL, $type);
+        common_element('Type', null, $type);
         if ($params) {
             foreach ($params as $param) {
-                common_element('Type', NULL, $param);
+                common_element('Type', null, $param);
             }
         }
         if ($sigs) {
             foreach ($sigs as $sig) {
-                common_element('Type', NULL, $sig);
+                common_element('Type', null, $sig);
             }
         }
         if ($localId) {
-            common_element('LocalID', NULL, $localId);
+            common_element('LocalID', null, $localId);
         }
         common_element_end('Service');
     }
diff --git a/actions/recoverpassword.php b/actions/recoverpassword.php
index 1263fee9b..068d582fa 100644
--- a/actions/recoverpassword.php
+++ b/actions/recoverpassword.php
@@ -132,12 +132,12 @@ class RecoverpasswordAction extends Action {
         unset($_SESSION['tempuser']);
     }
 
-    function show_top($msg=NULL) {
+    function show_top($msg=null) {
         if ($msg) {
             common_element('div', 'error', $msg);
         } else {
             common_element_start('div', 'instructions');
-            common_element('p', NULL, 
+            common_element('p', null, 
                            _('If you\'ve forgotten or lost your' .
                               ' password, you can get a new one sent to' .
                               ' the email address you have stored ' .
@@ -146,7 +146,7 @@ class RecoverpasswordAction extends Action {
         }
     }
 
-    function show_password_top($msg=NULL) {
+    function show_password_top($msg=null) {
         if ($msg) {
             common_element('div', 'error', $msg);
         } else {
@@ -156,9 +156,9 @@ class RecoverpasswordAction extends Action {
         }
     }
 
-    function show_form($msg=NULL) {
+    function show_form($msg=null) {
 
-        common_show_header(_('Recover password'), NULL,
+        common_show_header(_('Recover password'), null,
         $msg, array($this, 'show_top'));
 
         common_element_start('form', array('method' => 'post',
@@ -173,9 +173,9 @@ class RecoverpasswordAction extends Action {
         common_show_footer();
     }
 
-    function show_password_form($msg=NULL) {
+    function show_password_form($msg=null) {
 
-        common_show_header(_('Reset password'), NULL,
+        common_show_header(_('Reset password'), null,
         $msg, array($this, 'show_password_top'));
 
         common_element_start('form', array('method' => 'post',
@@ -224,7 +224,7 @@ class RecoverpasswordAction extends Action {
             $confirm_email = Confirm_address::staticGet('user_id', $user->id);
             if ($confirm_email && $confirm_email->address_type != 'email') {
                 # Skip non-email confirmations
-                $confirm_email = NULL;
+                $confirm_email = null;
             }
         }
 
@@ -267,7 +267,7 @@ class RecoverpasswordAction extends Action {
         mail_to_user($user, _('Password recovery requested'), $body, $confirm->address);
 
         common_show_header(_('Password recovery requested'));
-        common_element('p', NULL,
+        common_element('p', null,
                        _('Instructions for recovering your password ' .
                           'have been sent to the email address registered to your ' .
                           'account.'));
@@ -324,7 +324,7 @@ class RecoverpasswordAction extends Action {
         common_real_login(true);
 
         common_show_header(_('Password saved.'));
-        common_element('p', NULL, _('New password successfully saved. ' .
+        common_element('p', null, _('New password successfully saved. ' .
                                      'You are now logged in.'));
         common_show_footer();
     }
diff --git a/actions/register.php b/actions/register.php
index 011aa3f09..f3eaf6122 100644
--- a/actions/register.php
+++ b/actions/register.php
@@ -149,7 +149,7 @@ class RegisterAction extends Action {
         return ($user !== false);
     }
 
-    function show_top($error=NULL) {
+    function show_top($error=null) {
         if ($error) {
             common_element('p', 'error', $error);
         } else {
@@ -164,7 +164,7 @@ class RegisterAction extends Action {
         }
     }
 
-    function show_form($error=NULL) {
+    function show_form($error=null) {
         global $config;
 
         $code = $this->trimmed('code');
@@ -178,7 +178,7 @@ class RegisterAction extends Action {
             return;
         }
 
-        common_show_header(_('Register'), NULL, $error, array($this, 'show_top'));
+        common_show_header(_('Register'), null, $error, array($this, 'show_top'));
         common_element_start('form', array('method' => 'post',
                                            'id' => 'login',
                                            'action' => common_local_url('register')));
diff --git a/actions/remotesubscribe.php b/actions/remotesubscribe.php
index 14e8cb068..be2cb1025 100644
--- a/actions/remotesubscribe.php
+++ b/actions/remotesubscribe.php
@@ -55,7 +55,7 @@ class RemotesubscribeAction extends Action {
                   ' enter your profile URL below.');
     }
 
-    function show_top($err=NULL) {
+    function show_top($err=null) {
         if ($err) {
             common_element('div', 'error', $err);
         } else {
@@ -67,10 +67,10 @@ class RemotesubscribeAction extends Action {
         }
     }
 
-    function show_form($err=NULL) {
+    function show_form($err=null) {
         $nickname = $this->trimmed('nickname');
         $profile = $this->trimmed('profile_url');
-        common_show_header(_('Remote subscribe'), NULL, $err,
+        common_show_header(_('Remote subscribe'), null, $err,
                            array($this, 'show_top'));
         # id = remotesubscribe conflicts with the
         # button on profile page
@@ -153,7 +153,7 @@ class RemotesubscribeAction extends Action {
     }
 
     function get_user() {
-        $user = NULL;
+        $user = null;
         $nickname = $this->trimmed('nickname');
         if ($nickname) {
             $user = User::staticGet('nickname', $nickname);
@@ -173,7 +173,7 @@ class RemotesubscribeAction extends Action {
         $oauth_services = omb_get_services($xrds, OAUTH_DISCOVERY);
 
         if (!$oauth_services) {
-            return NULL;
+            return null;
         }
 
         $oauth_service = $oauth_services[0];
@@ -181,17 +181,17 @@ class RemotesubscribeAction extends Action {
         $oauth_xrd = $this->getXRD($oauth_service, $xrds);
 
         if (!$oauth_xrd) {
-            return NULL;
+            return null;
         }
 
         if (!$this->addServices($oauth_xrd, $oauth_endpoints, $omb)) {
-            return NULL;
+            return null;
         }
 
         $omb_services = omb_get_services($xrds, OMB_NAMESPACE);
 
         if (!$omb_services) {
-            return NULL;
+            return null;
         }
 
         $omb_service = $omb_services[0];
@@ -199,23 +199,23 @@ class RemotesubscribeAction extends Action {
         $omb_xrd = $this->getXRD($omb_service, $xrds);
 
         if (!$omb_xrd) {
-            return NULL;
+            return null;
         }
 
         if (!$this->addServices($omb_xrd, $omb_endpoints, $omb)) {
-            return NULL;
+            return null;
         }
 
         # XXX: check that we got all the services we needed
 
         foreach (array_merge($omb_endpoints, $oauth_endpoints) as $type) {
             if (!array_key_exists($type, $omb) || !$omb[$type]) {
-                return NULL;
+                return null;
             }
         }
 
         if (!omb_local_id($omb[OAUTH_ENDPOINT_REQUEST])) {
-            return NULL;
+            return null;
         }
 
         return $omb;
@@ -225,7 +225,7 @@ class RemotesubscribeAction extends Action {
         $uri = omb_service_uri($main_service);
         if (strpos($uri, "#") !== 0) {
             # FIXME: more rigorous handling of external service definitions
-            return NULL;
+            return null;
         }
         $id = substr($uri, 1);
         $nodes = $main_xrds->allXrdNodes;
@@ -239,7 +239,7 @@ class RemotesubscribeAction extends Action {
                 return new Auth_Yadis_XRDS($parser, $bogus_nodes);
             }
         }
-        return NULL;
+        return null;
     }
 
     function addServices($xrd, $types, &$omb) {
@@ -267,12 +267,12 @@ class RemotesubscribeAction extends Action {
         $params = array();
         parse_str($parsed['query'], $params);
 
-        $req = OAuthRequest::from_consumer_and_token($con, NULL, "POST", $url, $params);
+        $req = OAuthRequest::from_consumer_and_token($con, null, "POST", $url, $params);
 
         $listener = omb_local_id($omb[OAUTH_ENDPOINT_REQUEST]);
 
         if (!$listener) {
-            return NULL;
+            return null;
         }
 
         $req->set_parameter('omb_listener', $listener);
@@ -280,7 +280,7 @@ class RemotesubscribeAction extends Action {
 
         # XXX: test to see if endpoint accepts this signature method
 
-        $req->sign_request(omb_hmac_sha1(), $con, NULL);
+        $req->sign_request(omb_hmac_sha1(), $con, null);
 
         # We re-use this tool's fetcher, since it's pretty good
 
@@ -291,7 +291,7 @@ class RemotesubscribeAction extends Action {
                                  array('User-Agent' => 'Laconica/' . LACONICA_VERSION));
 
         if ($result->status != 200) {
-            return NULL;
+            return null;
         }
 
         parse_str($result->body, $return);
diff --git a/actions/repliesrss.php b/actions/repliesrss.php
index 3689ea1f8..9652ae9ea 100644
--- a/actions/repliesrss.php
+++ b/actions/repliesrss.php
@@ -25,7 +25,7 @@ require_once(INSTALLDIR.'/lib/rssaction.php');
 
 class RepliesrssAction extends Rss10Action {
 
-    var $user = NULL;
+    var $user = null;
 
     function init() {
         $nickname = $this->trimmed('nickname');
@@ -71,9 +71,9 @@ class RepliesrssAction extends Rss10Action {
         $user = $this->user;
         $profile = $user->getProfile();
         if (!$profile) {
-            return NULL;
+            return null;
         }
         $avatar = $profile->getAvatar(AVATAR_PROFILE_SIZE);
-        return ($avatar) ? $avatar->url : NULL;
+        return ($avatar) ? $avatar->url : null;
     }
 }
\ No newline at end of file
diff --git a/actions/showmessage.php b/actions/showmessage.php
index f35f3eede..a5e03c72d 100644
--- a/actions/showmessage.php
+++ b/actions/showmessage.php
@@ -53,7 +53,7 @@ class ShowmessageAction extends MailboxAction {
     function get_title($user, $page) {
         $message = $this->get_message();
         if (!$message) {
-            return NULL;
+            return null;
         }
         
         if ($user->id == $message->from_profile) {
@@ -85,7 +85,7 @@ class ShowmessageAction extends MailboxAction {
             return $message->getFrom();
         } else {
             # This shouldn't happen
-            return NULL;
+            return null;
         }
     }
     
diff --git a/actions/shownotice.php b/actions/shownotice.php
index 74d197ed1..04af61a6f 100644
--- a/actions/shownotice.php
+++ b/actions/shownotice.php
@@ -23,9 +23,9 @@ require_once(INSTALLDIR.'/lib/stream.php');
 
 class ShownoticeAction extends StreamAction {
 
-    var $notice = NULL;
-    var $profile = NULL;
-    var $avatar = NULL;
+    var $notice = null;
+    var $profile = null;
+    var $avatar = null;
 
     function prepare($args) {
 
@@ -73,7 +73,7 @@ class ShownoticeAction extends StreamAction {
         common_show_header(sprintf(_('%1$s\'s status on %2$s'),
                                    $this->profile->nickname,
                                    common_exact_date($this->notice->created)),
-                           array($this, 'show_header'), NULL,
+                           array($this, 'show_header'), null,
                            array($this, 'show_top'));
 
         common_element_start('ul', array('id' => 'notices'));
diff --git a/actions/showstream.php b/actions/showstream.php
index f8525348d..485c2e3d1 100644
--- a/actions/showstream.php
+++ b/actions/showstream.php
@@ -285,7 +285,7 @@ class ShowstreamAction extends StreamAction {
 
         common_element_start('div', array('id' => 'subscriptions'));
 
-        common_element('h2', NULL, _('Subscriptions'));
+        common_element('h2', null, _('Subscriptions'));
 
         if ($subs_count > 0) {
 
@@ -415,7 +415,7 @@ class ShowstreamAction extends StreamAction {
 
     function show_last_notice($profile) {
 
-        common_element('h2', NULL, _('Currently'));
+        common_element('h2', null, _('Currently'));
 
         $notice = $profile->getCurrentNotice();
 
diff --git a/actions/smssettings.php b/actions/smssettings.php
index 506801e97..71ab39514 100644
--- a/actions/smssettings.php
+++ b/actions/smssettings.php
@@ -28,7 +28,7 @@ class SmssettingsAction extends EmailsettingsAction {
         return _('You can receive SMS messages through email from %%site.name%%.');
     }
 
-    function show_form($msg=NULL, $success=false) {
+    function show_form($msg=null, $success=false) {
         $user = common_current_user();
         $this->form_header(_('SMS Settings'), $msg, $success);
         common_element_start('form', array('method' => 'post',
@@ -36,7 +36,7 @@ class SmssettingsAction extends EmailsettingsAction {
                                            'action' =>
                                            common_local_url('smssettings')));
         common_hidden('token', common_session_token());
-        common_element('h2', NULL, _('Address'));
+        common_element('h2', null, _('Address'));
 
         if ($user->sms) {
             common_element_start('p');
@@ -60,12 +60,12 @@ class SmssettingsAction extends EmailsettingsAction {
                 common_hidden('carrier', $confirm->address_extra);
                 common_element_end('p');
                 common_submit('cancel', _('Cancel'));
-                common_input('code', _('Confirmation code'), NULL,
+                common_input('code', _('Confirmation code'), null,
                              _('Enter the code you received on your phone.'));
                 common_submit('confirm', _('Confirm'));
             } else {
                 common_input('sms', _('SMS Phone number'),
-                             ($this->arg('sms')) ? $this->arg('sms') : NULL,
+                             ($this->arg('sms')) ? $this->arg('sms') : null,
                              _('Phone number, no punctuation or spaces, with area code'));
                 $this->carrier_select();
                 common_submit('add', _('Add'));
@@ -73,7 +73,7 @@ class SmssettingsAction extends EmailsettingsAction {
         }
 
         if ($user->sms) {
-            common_element('h2', NULL, _('Incoming email'));
+            common_element('h2', null, _('Incoming email'));
             
             if ($user->incomingemail) {
                 common_element_start('p');
@@ -91,7 +91,7 @@ class SmssettingsAction extends EmailsettingsAction {
             common_submit('newincoming', _('New'));
         }
         
-        common_element('h2', NULL, _('Preferences'));
+        common_element('h2', null, _('Preferences'));
         
         common_checkbox('smsnotify',
                         _('Send me notices through SMS; I understand I may incur exorbitant charges from my carrier.'),
@@ -111,7 +111,7 @@ class SmssettingsAction extends EmailsettingsAction {
         if ($confirm->find(TRUE)) {
             return $confirm;
         } else {
-            return NULL;
+            return null;
         }
     }
 
@@ -268,9 +268,9 @@ class SmssettingsAction extends EmailsettingsAction {
 
         $user->query('BEGIN');
         $original = clone($user);
-        $user->sms = NULL;
-        $user->carrier = NULL;        
-        $user->smsemail = NULL;        
+        $user->sms = null;
+        $user->carrier = null;        
+        $user->smsemail = null;        
         $result = $user->updateKeys($original);
         if (!$result) {
             common_log_db_error($user, 'UPDATE', __FILE__);
diff --git a/actions/subedit.php b/actions/subedit.php
index 1d095ab9a..db935eb28 100644
--- a/actions/subedit.php
+++ b/actions/subedit.php
@@ -21,7 +21,7 @@ if (!defined('LACONICA')) { exit(1); }
 
 class SubeditAction extends Action {
 
-    var $profile = NULL;
+    var $profile = null;
 
     function prepare($args) {
 
diff --git a/actions/tagother.php b/actions/tagother.php
index 832671ae7..4691fef07 100644
--- a/actions/tagother.php
+++ b/actions/tagother.php
@@ -49,12 +49,12 @@ class TagotherAction extends Action {
         }
     }
 
-    function show_form($profile, $error=NULL) {
+    function show_form($profile, $error=null) {
 
         $user = common_current_user();
 
         common_show_header(_('Tag a person'),
-                           NULL, array($profile, $error), array($this, 'show_top'));
+                           null, array($profile, $error), array($this, 'show_top'));
 
         $avatar = $profile->getAvatar(AVATAR_PROFILE_SIZE);
 
@@ -178,13 +178,13 @@ class TagotherAction extends Action {
         }
     }
 
-    function show_top($arr = NULL) {
+    function show_top($arr = null) {
         list($profile, $error) = $arr;
         if ($error) {
             common_element('p', 'error', $error);
         } else {
             common_element_start('div', 'instructions');
-            common_element('p', NULL,
+            common_element('p', null,
                            _('Use this form to add tags to your subscribers or subscriptions.'));
             common_element_end('div');
         }
diff --git a/actions/tagrss.php b/actions/tagrss.php
index 45639fec4..6199a285d 100644
--- a/actions/tagrss.php
+++ b/actions/tagrss.php
@@ -41,7 +41,7 @@ class TagrssAction extends Rss10Action {
         $tag = $this->tag;
 
         if (is_null($tag)) {
-            return NULL;
+            return null;
         }
 
         $notice = Notice_tag::getStream($tag->tag, 0, ($limit == 0) ? NOTICES_PER_PAGE : $limit);
diff --git a/actions/twitapidirect_messages.php b/actions/twitapidirect_messages.php
index 2e3b50173..7adb4eadd 100644
--- a/actions/twitapidirect_messages.php
+++ b/actions/twitapidirect_messages.php
@@ -228,12 +228,12 @@ class Twitapidirect_messagesAction extends TwitterapiAction {
         $this->init_document('rss');
 
         common_element_start('channel');
-        common_element('title', NULL, $title);
+        common_element('title', null, $title);
 
-        common_element('link', NULL, $link);
-        common_element('description', NULL, $subtitle);
-        common_element('language', NULL, 'en-us');
-        common_element('ttl', NULL, '40');
+        common_element('link', null, $link);
+        common_element('description', null, $subtitle);
+        common_element('language', null, 'en-us');
+        common_element('ttl', null, '40');
 
         if (is_array($message)) {
             foreach ($message as $m) {
@@ -256,12 +256,12 @@ class Twitapidirect_messagesAction extends TwitterapiAction {
 
         $this->init_document('atom');
 
-        common_element('title', NULL, $title);
+        common_element('title', null, $title);
         $siteserver = common_config('site', 'server');
-        common_element('id', NULL, "tag:$siteserver,2008:DirectMessage");
-        common_element('link', array('href' => $link, 'rel' => 'alternate', 'type' => 'text/html'), NULL);
-        common_element('updated', NULL, common_date_iso8601(strftime('%c')));
-        common_element('subtitle', NULL, $subtitle);
+        common_element('id', null, "tag:$siteserver,2008:DirectMessage");
+        common_element('link', array('href' => $link, 'rel' => 'alternate', 'type' => 'text/html'), null);
+        common_element('updated', null, common_date_iso8601(strftime('%c')));
+        common_element('subtitle', null, $subtitle);
 
         if (is_array($message)) {
             foreach ($message as $m) {
diff --git a/actions/twitapifriendships.php b/actions/twitapifriendships.php
index d352b933b..a52f0fe4d 100644
--- a/actions/twitapifriendships.php
+++ b/actions/twitapifriendships.php
@@ -138,7 +138,7 @@ class TwitapifriendshipsAction extends TwitterapiAction {
         switch ($apidata['content-type']) {
          case 'xml':
             $this->init_document('xml');
-            common_element('friends', NULL, $result);
+            common_element('friends', null, $result);
             $this->end_document('xml');
             break;
          case 'json':
diff --git a/actions/twitapihelp.php b/actions/twitapihelp.php
index d268b7c82..f0e9adfdb 100644
--- a/actions/twitapihelp.php
+++ b/actions/twitapihelp.php
@@ -32,7 +32,7 @@ class TwitapihelpAction extends TwitterapiAction {
 
         if ($apidata['content-type'] == 'xml') {
             $this->init_document('xml');
-            common_element('ok', NULL, 'true');
+            common_element('ok', null, 'true');
             $this->end_document('xml');
         } elseif ($apidata['content-type'] == 'json') {
             $this->init_document('json');
diff --git a/actions/twitapistatuses.php b/actions/twitapistatuses.php
index c33643a3c..ffa94b309 100644
--- a/actions/twitapistatuses.php
+++ b/actions/twitapistatuses.php
@@ -112,7 +112,7 @@ class TwitapistatusesAction extends TwitterapiAction {
 
         $since = strtotime($this->arg('since'));
 
-        $user = $this->get_user(NULL, $apidata);
+        $user = $this->get_user(null, $apidata);
         $this->auth_user = $user;
 
         $profile = $user->getProfile();
@@ -200,7 +200,7 @@ class TwitapistatusesAction extends TwitterapiAction {
         # FriendFeed's SUP protocol
         # Also added RSS and Atom feeds
 
-        $suplink = common_local_url('sup', NULL, $user->id);
+        $suplink = common_local_url('sup', null, $user->id);
         header('X-SUP-ID: '.$suplink);
 
         # XXX: since
@@ -291,7 +291,7 @@ class TwitapistatusesAction extends TwitterapiAction {
             $apidata['api_arg'] = $n->id;
         } else {
 
-            $reply_to = NULL;
+            $reply_to = null;
 
             if ($in_reply_to_status_id) {
 
diff --git a/actions/twittersettings.php b/actions/twittersettings.php
index e300e699a..8cbd39fbd 100644
--- a/actions/twittersettings.php
+++ b/actions/twittersettings.php
@@ -30,10 +30,10 @@ class TwittersettingsAction extends SettingsAction {
             'and subscribe to Twitter friends already here.');
     }
 
-    function show_form($msg=NULL, $success=false) {
+    function show_form($msg=null, $success=false) {
         $user = common_current_user();
         $profile = $user->getProfile();
-        $fuser = NULL;
+        $fuser = null;
         $flink = Foreign_link::getByUserID($user->id, 1); // 1 == Twitter
 
         if ($flink) {
@@ -47,7 +47,7 @@ class TwittersettingsAction extends SettingsAction {
                                            common_local_url('twittersettings')));
         common_hidden('token', common_session_token());
 
-        common_element('h2', NULL, _('Twitter Account'));
+        common_element('h2', null, _('Twitter Account'));
 
         if ($fuser) {
             common_element_start('p');
@@ -67,7 +67,7 @@ class TwittersettingsAction extends SettingsAction {
             common_password('twitter_password', _('Twitter password'));
         }
 
-        common_element('h2', NULL, _('Preferences'));
+        common_element('h2', null, _('Preferences'));
 
         common_checkbox('noticesync', _('Automatically send my notices to Twitter.'),
                         ($flink) ? ($flink->noticesync & FOREIGN_NOTICE_SEND) : true);
@@ -126,7 +126,7 @@ class TwittersettingsAction extends SettingsAction {
 
         if ($friends_count > 0) {
 
-            common_element('h3', NULL, _('Twitter Friends'));
+            common_element('h3', null, _('Twitter Friends'));
             common_element_start('div', array('id' => 'subscriptions'));
             common_element_start('ul', array('id' => 'subscriptions_avatars'));
 
diff --git a/actions/unblock.php b/actions/unblock.php
index 6a86c2bf0..51ec0ae57 100644
--- a/actions/unblock.php
+++ b/actions/unblock.php
@@ -21,7 +21,7 @@ if (!defined('LACONICA')) { exit(1); }
 
 class UnblockAction extends Action {
 
-    var $profile = NULL;
+    var $profile = null;
 
     function prepare($args) {
 
diff --git a/actions/userauthorization.php b/actions/userauthorization.php
index 97809f197..58ec36fc8 100644
--- a/actions/userauthorization.php
+++ b/actions/userauthorization.php
@@ -81,7 +81,7 @@ class UserauthorizationAction extends Action {
         $avatar = $req->get_parameter('omb_listenee_avatar');
 
         common_show_header(_('Authorize subscription'));
-        common_element('p', NULL, _('Please check these details to make sure '.
+        common_element('p', null, _('Please check these details to make sure '.
                                      'that you want to subscribe to this user\'s notices. '.
                                      'If you didn\'t just ask to subscribe to someone\'s notices, '.
                                      'click "Cancel".'));
@@ -320,7 +320,7 @@ class UserauthorizationAction extends Action {
 
     function show_accept_message($tok) {
         common_show_header(_('Subscription authorized'));
-        common_element('p', NULL,
+        common_element('p', null,
                        _('The subscription has been authorized, but no '.
                           'callback URL was passed. Check with the site\'s instructions for '.
                           'details on how to authorize the subscription. Your subscription token is:'));
@@ -330,7 +330,7 @@ class UserauthorizationAction extends Action {
 
     function show_reject_message($tok) {
         common_show_header(_('Subscription rejected'));
-        common_element('p', NULL,
+        common_element('p', null,
                        _('The subscription has been rejected, but no '.
                           'callback URL was passed. Check with the site\'s instructions for '.
                           'details on how to fully reject the subscription.'));
diff --git a/actions/userbyid.php b/actions/userbyid.php
index 4eab8758c..3fa92e9ce 100644
--- a/actions/userbyid.php
+++ b/actions/userbyid.php
@@ -38,7 +38,7 @@ class UserbyidAction extends Action {
 
         // support redirecting to FOAF rdf/xml if the agent prefers it
         $page_prefs = 'application/rdf+xml,text/html,application/xhtml+xml,application/xml;q=0.3,text/xml;q=0.2';
-        $httpaccept = isset($_SERVER['HTTP_ACCEPT']) ? $_SERVER['HTTP_ACCEPT'] : NULL;
+        $httpaccept = isset($_SERVER['HTTP_ACCEPT']) ? $_SERVER['HTTP_ACCEPT'] : null;
         $type = common_negotiate_type(common_accept_to_prefs($httpaccept),
                                       common_accept_to_prefs($page_prefs));
         $page = $type == 'application/rdf+xml' ? 'foaf' : 'showstream';
diff --git a/actions/userrss.php b/actions/userrss.php
index b5cb5a40a..6089718ae 100644
--- a/actions/userrss.php
+++ b/actions/userrss.php
@@ -25,7 +25,7 @@ require_once(INSTALLDIR.'/lib/rssaction.php');
 
 class UserrssAction extends Rss10Action {
 
-    var $user = NULL;
+    var $user = null;
 
     function init() {
         $nickname = $this->trimmed('nickname');
@@ -44,7 +44,7 @@ class UserrssAction extends Rss10Action {
         $user = $this->user;
         
         if (is_null($user)) {
-            return NULL;
+            return null;
         }
         
         $notice = $user->getNotices(0, ($limit == 0) ? NOTICES_PER_PAGE : $limit);
@@ -74,16 +74,16 @@ class UserrssAction extends Rss10Action {
         if (!$profile) {
             common_log_db_error($user, 'SELECT', __FILE__);
             $this->server_error(_('User without matching profile'));
-            return NULL;
+            return null;
         }
         $avatar = $profile->getAvatar(AVATAR_PROFILE_SIZE);
-        return ($avatar) ? $avatar->url : NULL;
+        return ($avatar) ? $avatar->url : null;
     }
 
     # override parent to add X-SUP-ID URL
     
     function init_rss($limit=0) {
-        $url = common_local_url('sup', NULL, $this->user->id);
+        $url = common_local_url('sup', null, $this->user->id);
         header('X-SUP-ID: '.$url);
         parent::init_rss($limit);
     }
diff --git a/actions/xrds.php b/actions/xrds.php
index 9788c87aa..54baf64be 100644
--- a/actions/xrds.php
+++ b/actions/xrds.php
@@ -50,7 +50,7 @@ class XrdsAction extends Action {
                                           'xmlns:simple' => 'http://xrds-simple.net/core/1.0',
                                           'version' => '2.0'));
 
-        common_element('Type', NULL, 'xri://$xrds*simple');
+        common_element('Type', null, 'xri://$xrds*simple');
 
         $this->show_service(OAUTH_ENDPOINT_REQUEST,
                             common_local_url('requesttoken'),
@@ -69,7 +69,7 @@ class XrdsAction extends Action {
                             array(OAUTH_HMAC_SHA1));
 
         $this->show_service(OAUTH_ENDPOINT_RESOURCE,
-                            NULL,
+                            null,
                             array(OAUTH_AUTH_HEADER, OAUTH_POST_BODY),
                             array(OAUTH_HMAC_SHA1));
 
@@ -82,7 +82,7 @@ class XrdsAction extends Action {
                                           'xmlns:simple' => 'http://xrds-simple.net/core/1.0',
                                           'version' => '2.0'));
 
-        common_element('Type', NULL, 'xri://$xrds*simple');
+        common_element('Type', null, 'xri://$xrds*simple');
 
         $this->show_service(OMB_ENDPOINT_POSTNOTICE,
                             common_local_url('postnotice'));
@@ -95,7 +95,7 @@ class XrdsAction extends Action {
         common_element_start('XRD', array('xmlns' => 'xri://$xrd*($v*2.0)',
                                           'version' => '2.0'));
 
-        common_element('Type', NULL, 'xri://$xrds*simple');
+        common_element('Type', null, 'xri://$xrds*simple');
 
         $this->show_service(OAUTH_DISCOVERY,
                             '#oauth');
@@ -108,24 +108,24 @@ class XrdsAction extends Action {
         common_end_xml();
     }
 
-    function show_service($type, $uri, $params=NULL, $sigs=NULL, $localId=NULL) {
+    function show_service($type, $uri, $params=null, $sigs=null, $localId=null) {
         common_element_start('Service');
         if ($uri) {
-            common_element('URI', NULL, $uri);
+            common_element('URI', null, $uri);
         }
-        common_element('Type', NULL, $type);
+        common_element('Type', null, $type);
         if ($params) {
             foreach ($params as $param) {
-                common_element('Type', NULL, $param);
+                common_element('Type', null, $param);
             }
         }
         if ($sigs) {
             foreach ($sigs as $sig) {
-                common_element('Type', NULL, $sig);
+                common_element('Type', null, $sig);
             }
         }
         if ($localId) {
-            common_element('LocalID', NULL, $localId);
+            common_element('LocalID', null, $localId);
         }
         common_element_end('Service');
     }