[vreg] move base registry implementation to logilab.common. Closes #1916014 A new logilab.common.registry module has been created with content from * cw.vreg (the whole things that was in there) * cw.appobject (base selectors and all). In the process, we've done some renaming: * former selector functions are now known as "predicate", though you still use predicates to build an object'selector * hence `objectify_selector` decorator is now `objectify_predicate` * the top level registry is now `RegistryStore` (was `VRegistry`) Also there is no more need for the @lltrace decorator. On the CubicWeb side, the `selectors` module has been renamed to `predicates`. There should be full backward compat with proper deprecation warnings.

/* -*- sql -*- 

   mysql specific registered procedures, 

*/

/* XXX limit_size version dealing with format as postgres version does.
   XXX mysql doesn't support overloading, each function should have a different name
       
   NOTE: fulltext renamed since it cause a mysql name conflict
 */

CREATE FUNCTION text_limit_size(vfulltext TEXT, maxsize INT)
RETURNS TEXT
NO SQL
BEGIN
    IF LENGTH(vfulltext) < maxsize THEN
       RETURN vfulltext;
    ELSE
       RETURN SUBSTRING(vfulltext from 1 for maxsize) || '...';
    END IF;
END ;;