use RichString

schema.py

 """
 :organization: Logilab
-:copyright: 2003-2008 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
+:copyright: 2003-2009 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
 :contact: http://www.logilab.fr/ -- mailto:contact@logilab.fr
 """
@@ -4,6 +4,5 @@
 :contact: http://www.logilab.fr/ -- mailto:contact@logilab.fr
 """
-from cubicweb.schema import format_constraint
 
 class Comment(MetaUserEntityType):
     """a comment is a reply about another entity"""
@@ -7,10 +6,8 @@
 
 class Comment(MetaUserEntityType):
     """a comment is a reply about another entity"""
-    content_format = String(meta=True, internationalizable=True, maxsize=50,
-                            default='text/rest', constraints=[format_constraint])
-    content = String(required=True, fulltextindexed=True)
-    
+    content = RichString(required=True, fulltextindexed=True)
+
     comments = SubjectRelation('Comment', cardinality='1*', composite='object')
     #comments = SubjectRelation('*')