Architecture
============

``boltons`` has a minimalist architecture: remain as consistent, and
self-contained as possible, with an eye toward maintaining its range
of use cases and usage patterns as wide as possible.

.. _arch_integration:

Integration
-----------

Utility libraries are often used extensively within a project, and
because they are not often fundamental to the architecture of the
application, simplicity and stability may take precedence over version
recency. In these cases, developers can:

  1. Copy the whole ``boltons`` package into a project.
  2. Copy just the ``utils.py`` file that a project requires.

Boltons take this into account by design.  The ``boltons`` package
depends on no packages, making it easy for inclusion into a
project. Furthermore, virtually all individual modules have been
written to be as self-contained as possible, allowing cherrypicking of
functionality into projects.

Design of a ``bolton``
----------------------

``boltons`` aims to be a living library, an ever-expanding collection
of tested and true utilities. For a ``bolton`` to be a ``bolton``, it
should:

  1. Be pure-Python and as self-contained as possible.
  2. Perform a common task or fulfill a common role.
  3. Demonstrate and mitigate some insufficiency in the standard library.
  4. Strive for the standard set forth by the standard library by
     striking a balance between best practice and "good enough",
     correctness and common sense.
  5. Have approachable documentation with at least one helpful
     :mod:`doctest`, links to relevant standard library functionality, as
     well as any 3rd-party packages that provide further capabilities.

Themes of ``boltons``
---------------------

``boltons`` has had a wide variety of inspirations over the years, but
a definite set of themes have emerged:

1. From the Python docs:

   1. :mod:`~boltons.queueutils` - `heapq docs`_
   2. :mod:`~boltons.iterutils` - `itertools docs`_
   3. :mod:`~boltons.tzutils` - `datetime docs`_

2. Reimplementations and tweaks of the standard library:

   1. :func:`boltons.fileutils.copytree` - :func:`shutil.copytree`
   2. :class:`boltons.namedutils.namedtuple` - :func:`collections.namedtuple`

3. One-off implementations discovered in multiple other libraries' ``utils.py`` or equivalent

   1. :func:`boltons.strutils.slugify`
   2. :func:`boltons.strutils.bytes2human`
   3. :func:`boltons.timeutils.relative_time`

4. More powerful multi-purpose data structures

   1. :class:`boltons.dictutils.OrderedMultiDict`
   2. :class:`boltons.setutils.IndexedSet`
   3. :class:`boltons.listutils.BList`
   4. :class:`boltons.namedutils.namedlist`
   5. :class:`boltons.tableutils.Table`

5. Personal practice and experience

   1. :mod:`boltons.debugutils`
   2. :mod:`boltons.gcutils`
   3. :mod:`boltons.tbutils`


.. _heapq docs: https://docs.python.org/2/library/heapq.html#priority-queue-implementation-notes
.. _itertools docs: https://docs.python.org/2/library/itertools.html#recipes
.. _datetime docs: https://docs.python.org/2/library/datetime.html#tzinfo-objects