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+The Registry, selectors and application objects
+===============================================
+
+This chapter deals with some of the  core concepts of the |cubicweb| framework
+which make it different from other frameworks (and maybe not easy to
+grasp at a first glance). To be able to do advanced development with
+|cubicweb| you need a good understanding of what is explained below.
+
+This chapter goes deep into details. You don't have to remember them
+all but keep it in mind so you can go back there later.
+
+An overview of AppObjects, the VRegistry and Selectors is given in the
+:ref:`VRegistryIntro` chapter.
+
+.. autodocstring:: cubicweb.cwvreg
+.. autodocstring:: cubicweb.predicates
+.. automodule:: cubicweb.appobject
+
+Base predicates
+---------------
+
+Predicates are scoring functions that are called by the registry to tell whenever
+an appobject can be selected in a given context. Predicates may be chained
+together using operators to build a selector. A selector is the glue that tie
+views to the data model or whatever input context. Using them appropriately is an
+essential part of the construction of well behaved cubes.
+
+Of course you may have to write your own set of predicates as your needs grows
+and you get familiar with the framework (see :ref:`CustomPredicates`).
+
+Here is a description of generic predicates provided by CubicWeb that should suit
+most of your needs.
+
+Bare predicates
+~~~~~~~~~~~~~~~
+Those predicates are somewhat dumb, which doesn't mean they're not (very) useful.
+
+.. autoclass:: cubicweb.appobject.yes
+.. autoclass:: cubicweb.predicates.match_kwargs
+.. autoclass:: cubicweb.predicates.appobject_selectable
+.. autoclass:: cubicweb.predicates.adaptable
+.. autoclass:: cubicweb.predicates.configuration_values
+
+
+Result set predicates
+~~~~~~~~~~~~~~~~~~~~~
+Those predicates are looking for a result set in the context ('rset' argument or
+the input context) and match or not according to its shape. Some of these
+predicates have different behaviour if a particular cell of the result set is
+specified using 'row' and 'col' arguments of the input context or not.
+
+.. autoclass:: cubicweb.predicates.none_rset
+.. autoclass:: cubicweb.predicates.any_rset
+.. autoclass:: cubicweb.predicates.nonempty_rset
+.. autoclass:: cubicweb.predicates.empty_rset
+.. autoclass:: cubicweb.predicates.one_line_rset
+.. autoclass:: cubicweb.predicates.multi_lines_rset
+.. autoclass:: cubicweb.predicates.multi_columns_rset
+.. autoclass:: cubicweb.predicates.paginated_rset
+.. autoclass:: cubicweb.predicates.sorted_rset
+.. autoclass:: cubicweb.predicates.one_etype_rset
+.. autoclass:: cubicweb.predicates.multi_etypes_rset
+
+
+Entity predicates
+~~~~~~~~~~~~~~~~~
+Those predicates are looking for either an `entity` argument in the input context,
+or entity found in the result set ('rset' argument or the input context) and
+match or not according to entity's (instance or class) properties.
+
+.. autoclass:: cubicweb.predicates.non_final_entity
+.. autoclass:: cubicweb.predicates.is_instance
+.. autoclass:: cubicweb.predicates.score_entity
+.. autoclass:: cubicweb.predicates.rql_condition
+.. autoclass:: cubicweb.predicates.relation_possible
+.. autoclass:: cubicweb.predicates.partial_relation_possible
+.. autoclass:: cubicweb.predicates.has_related_entities
+.. autoclass:: cubicweb.predicates.partial_has_related_entities
+.. autoclass:: cubicweb.predicates.has_permission
+.. autoclass:: cubicweb.predicates.has_add_permission
+.. autoclass:: cubicweb.predicates.has_mimetype
+.. autoclass:: cubicweb.predicates.is_in_state
+.. autofunction:: cubicweb.predicates.on_fire_transition
+
+
+Logged user predicates
+~~~~~~~~~~~~~~~~~~~~~~
+Those predicates are looking for properties of the user issuing the request.
+
+.. autoclass:: cubicweb.predicates.match_user_groups
+
+
+Web request predicates
+~~~~~~~~~~~~~~~~~~~~~~
+Those predicates are looking for properties of *web* request, they can not be
+used on the data repository side.
+
+.. autoclass:: cubicweb.predicates.no_cnx
+.. autoclass:: cubicweb.predicates.anonymous_user
+.. autoclass:: cubicweb.predicates.authenticated_user
+.. autoclass:: cubicweb.predicates.match_form_params
+.. autoclass:: cubicweb.predicates.match_search_state
+.. autoclass:: cubicweb.predicates.match_context_prop
+.. autoclass:: cubicweb.predicates.match_context
+.. autoclass:: cubicweb.predicates.match_view
+.. autoclass:: cubicweb.predicates.primary_view
+.. autoclass:: cubicweb.predicates.contextual
+.. autoclass:: cubicweb.predicates.specified_etype_implements
+.. autoclass:: cubicweb.predicates.attribute_edited
+.. autoclass:: cubicweb.predicates.match_transition
+
+
+Other predicates
+~~~~~~~~~~~~~~~~
+.. autoclass:: cubicweb.predicates.match_exception
+.. autoclass:: cubicweb.predicates.debug_mode
+
+You'll also find some other (very) specific predicates hidden in other modules
+than :mod:`cubicweb.predicates`.