[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 -*-

.. _Part1:

--------------------------
Introduction to *CubicWeb*
--------------------------

This first part of the book offers different reading path to
discover the *CubicWeb* framework, provides a tutorial to get a quick
overview of its features and lists its key concepts.


.. toctree::
   :maxdepth: 2
   :numbered:

   history
   concepts.rst