Index: trunk/core/kernel/constants.php
===================================================================
diff -u -N -r7391 -r7855
--- trunk/core/kernel/constants.php	(.../constants.php)	(revision 7391)
+++ trunk/core/kernel/constants.php	(.../constants.php)	(revision 7855)
@@ -30,6 +30,7 @@
 	define('erFAIL',		-1);	// event finished working, but result is unsuccsessfull
 	define('erFATAL',		-2);	// event experienced FATAL error - no hooks should continue!
 	define('erPERM_FAIL',	-3);	// event failed on internal permission checking (user has not permission)
+	define('erSTOP',		-4);	// event requested to stop processing (don't parse templates)
 
 	// permission types
 	define('ptCATEGORY', 	0);
@@ -45,4 +46,8 @@
 		// don't show debugger buttons on front (if not overrided in "debug.php")
 		safeDefine('DBG_TOOLBAR_BUTTONS', 0);
 	}
+	
+	// common usage regular expressions
+	define('REGEX_EMAIL_USER', '[-a-zA-Z0-9!\#$%&*+\/=?^_`{|}~.]+');
+	define('REGEX_EMAIL_DOMAIN', '[a-zA-Z0-9]{1}[-.a-zA-Z0-9_]*\.[a-zA-Z]{2,6}');
 ?>
\ No newline at end of file