# HG changeset patch
# User Aurelien Campeas <aurelien.campeas@logilab.fr>
# Date 1244139700 -7200
# Node ID 296e897ab8e12f9dacd1ea632ff64af882888b42
# Parent  c865cc7100ca2fa5b78b415139e1f64e33665762
be more precise & helpful

diff -r c865cc7100ca -r 296e897ab8e1 doc/book/en/annexes/faq.rst
--- a/doc/book/en/annexes/faq.rst	Thu Jun 04 17:53:33 2009 +0200
+++ b/doc/book/en/annexes/faq.rst	Thu Jun 04 20:21:40 2009 +0200
@@ -273,14 +273,26 @@
 ---------------------------------------------------------------
 
   You just need to put the appropriate context manager around view/component
-  selection: ::
+  selection (one standard place in in vreg.py) : ::
+
+    def possible_objects(self, registry, *args, **kwargs):
+        """return an iterator on possible objects in a registry for this result set
 
-    from cubicweb.common.selectors import traced_selection
-    with traced_selection():
-        comp = self.vreg.select_object('contentnavigation', 'wfhistory',
-                                       self.req, rset, context='navcontentbottom')
+        actions returned are classes, not instances
+        """
+        from cubicweb.selectors import traced_selection
+        with traced_selection():
+            for vobjects in self.registry(registry).values():
+                try:
+                    yield self.select(vobjects, *args, **kwargs)
+                except NoSelectableObject:
+                    continue
 
-  This will yield additional WARNINGs, like this: ::
+  Don't forget the 'from __future__ improt with_statement' at the
+  module top-level.
+
+  This will yield additional WARNINGs, like this:
+  ::
 
     2009-01-09 16:43:52 - (cubicweb.selectors) WARNING: selector one_line_rset returned 0 for <class 'cubicweb.web.views.basecomponents.WFHistoryVComponent'>
 
@@ -351,4 +363,4 @@
 
     $ psql mydb
     mydb=> update cw_cwuser set cw_upassword='qHO8282QN5Utg' where cw_login='joe';
-    UPDATE 1
\ No newline at end of file
+    UPDATE 1