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.. include:: ../header.txt
===========================
Docutils Runtime Settings
===========================
:Author: David Goodger, Günter Milde
:Contact: docutils-develop@lists.sourceforge.net
:Date: $Date$
:Revision: $Revision$
:Copyright: This document has been placed in the public domain.
.. contents::
Introduction
============
Docutils runtime settings are assembled from several sources:
* Settings specifications of the selected components_,
* `configuration files`_ (if enabled), and
* command-line options (if enabled).
Docutils overlays default and explicitly specified values from these
sources such that settings behave the way we want and expect them to
behave.
Settings priority
=================
The sources are overlaid in the following order (later sources
overwrite earlier ones):
1. Defaults specified in the `settings_spec`__ and
`settings_defaults`__ attributes for each component_.
__ SettingsSpec.settings_spec_
__ SettingsSpec.settings_defaults_
2. Defaults specified in the `settings_default_overrides`__ attribute
for each component_.
__ SettingsSpec.settings_default_overrides_
3. Settings specified in the `settings_overrides`__ parameter of the
`convenience functions`_ resp. the `settings_overrides` attribute of
a `Publisher`_ instance.
__ `settings_overrides parameter`_
4. Settings specified in `active sections`_ of the `configuration files`_
in the order described in `Configuration File Sections & Entries`_
(if enabled).
5. Command line options (if enabled).
For details see the ``docutils/__init__.py``, ``docutils/core.py``, and
``docutils.frontend.py`` modules and the implementation description in
`Runtime Settings Processing`_.
.. _SettingsSpec:
SettingsSpec base class
=======================
.. note::
Implementation details will change with the move to replace the
deprecated optparse_ module with argparse_.
The `docutils.SettingsSpec` base class is inherited by Docutils
components_ and `frontend.OptionParser`.
It defines the following six **attributes**:
.. _SettingsSpec.settings_spec:
`settings_spec`
a sequence of
1. option group title (string or None)
2. description (string or None)
3. option tuples with
a) help text
b) options string(s)
c) dictionary with keyword arguments for `OptionParser.add_option()`_
and an optional "validator", a `frontend.validate_*()` function
that processes the values (e.g. convert to other data types).
For examples, see the source of ``frontend.OptionParser.settings_spec``
or the `settings_spec` attributes of the Docutils components_.
.. _SettingsSpec.settings_defaults:
`settings_defaults`
for purely programmatic settings
(not accessible from command line and configuration files).
.. _SettingsSpec.settings_default_overrides:
`settings_default_overrides`
to override defaults for settings
defined in other components' `setting_specs`.
`relative_path_settings`
listing settings containing filesystem paths.
.. _active sections:
`config_section`
the configuration file section specific to this
component.
`config_section_dependencies`
lists configuration files sections
that should also be read (before the `config_section`).
The last two attributes define which configuration file sections are
"active". See also `Configuration File Sections & Entries`_.
Glossary
========
.. _component:
components
----------
Docutils front-ends and applications combine a selection of
*components* of the `Docutils Project Model`_.
All components inherit the `SettingsSpec`_ base class.
This means that all instances of ``readers.Reader``, ``parsers.Parser``, and
``writers.Writer`` are also instances of ``docutils.SettingsSpec``.
For the determination of runtime settings, ``frontend.OptionParser`` and
the `settings_spec parameter`_ in application settings specifications
are treated as components as well.
.. _convenience function:
convenience functions
---------------------
Applications usually deploy Docutils by one of the
`Publisher convenience functions`_.
All convenience functions accept the following optional parameters:
.. _settings parameter:
`settings`
a ``frontend.Values`` instance.
If present, it must be complete.
No further runtime settings processing is done and the
following parameters have no effect.
.. _settings_spec parameter:
`settings_spec`
a `SettingsSpec`_ subclass or instance containing the settings
specification for the "Application" itself.
The instance is added to the components_ (after the generic
settings, parser, reader, and writer).
.. _settings_overrides parameter:
`settings_overrides`
a dictionary which is used to update the
defaults of the components' settings specifications.
.. _config_section parameter:
`config_section`
the name of an application-specific
`configuration file section`_ for this application.
Can be specified instead of a `settings_spec` (a new SettingsSpec_
instance that just defines a configuration section will be created)
or in addition to a `settings_spec`
(overriding its `config_section` attribute).
settings_spec
-------------
The name ``settings_spec`` may refer to
a) an instance of the SettingsSpec_ class, or
b) the data structure `SettingsSpec.settings_spec`_ which is used to
store settings details.
.. References:
.. _Publisher: publisher.html
.. _Publisher convenience functions:
publisher.html#publisher-convenience-functions
.. _front-end tools: ../user/tools.html
.. _configuration files:
.. _Docutils Configuration: ../user/config.html#configuration-files
.. _configuration file section:
.. _Configuration File Sections & Entries:
../user/config.html#configuration-file-sections-entries
.. _Docutils Project Model: ../peps/pep-0258.html#docutils-project-model
.. _Reader: ../peps/pep-0258.html#reader
.. _Runtime Settings Processing: ../dev/runtime-settings-processing.html
.. _optparse: https://docs.python.org/dev/library/optparse.html
.. _argparse: https://docs.python.org/dev/library/argparse.html
.. _OptionParser.add_option():
https://docs.python.org/dev/library/optparse.html
#optparse.OptionParser.add_option
|
