[rtags] Allow to 'derive' rtags
Since some releases, rtags (structure underlying uicfg) have selector and may be
copied using something like:
new_rtags = deepcopy(original_rtags)
new_rtags.__module__ = __name__
new_rtags.__select__ = custom_selector
The problem is that starting from that, both rtags wil diverge and changes in
original_rtags won't be considered, while we usually want to set a few specific
rules only in new_rtags. To fix this problem, this cset introduces the notion of
"derivated/parent" rtag, eg:
new_rtags = original_rtags.derive(__name__, custom_selector)
Beside easier copying, when using the above method changes in original_rtags
which are not overriden by new_rtags will be considered since it only hold its
specific rules but look among its parent chain for non-found keys.
Along the way, flake8 unittest_rtags.
Closes #16164880
.. -*- coding: utf-8 -*-
A little history...
===================
*CubicWeb* is a semantic web application framework that Logilab_ started
developing in 2001 as an offspring of its Narval_ research project. *CubicWeb*
is written in Python and includes a data server and a web engine.
Its data server publishes data federated from different sources like
SQL databases, LDAP directories, `VCS`_ repositories or even from other
CubicWeb data servers.
.. _`VCS`: http://en.wikipedia.org/wiki/Revision_control
Its web engine was designed to let the final user control what content to select
and how to display it. It allows one to browse the federated data sources and
display the results with the rendering that best fits the context. This
flexibility of the user interface gives back to the user some capabilities
usually only accessible to application developers.
*CubicWeb* has been developed by Logilab_ and used in-house for many years
before it was first installed for its clients in 2006 as version 2.
In 2008, *CubicWeb* version 3 became downloadable for free under the
terms of the LGPL license. Its community is now steadily growing
without hampering the fast-paced stream of changes thanks to the time
and energy originally put in the design of the framework.
.. _Narval: http://www.logilab.org/project/narval-moved
.. _Logilab: http://www.logilab.fr/