[Python-Dev] Extension to ConfigParser

[Fuzzyman]

Hello all,

In the past there has been some discussion about a new module to replace
ConfigParser. Most notably at
http://wiki.python.org/moin/ConfigParserShootout

Specific issues that could be addressed include :

* Simpler API
* Nested subsections
* List values
* Storing/converting datatypes
* Config file schema
* Keeps track of order of values

Plus other issues.

I'm the (co-)author of ConfigObj -
http://www.voidspace.org.uk/python/configobj.html

This is a reasonably mature project (now in it's fourth incarnation),
and is being used in projects like `Bazaar <http://www.bazaar-ng.org/>`_
and `PlanetPlus <http://planetplus.python-hosting.com/>`_.

It occurs to me that the ConfigObj API and syntax is *almost* fully
compatible with ConfigParser.

It would be possible to extend to the ConfigObj API to be backwards
compatible with ConfigParser. This would bring the added benefits of
ConfigObj, without needing to add an extra module to the standard library.

Well nearly. ConfigObj supports config file schema with (optional) type
conversion, through a companion module called validate. This could be
included or left as an added option.

Anyway. If this stands a *chance* of acceptance, I'll write the PEP (and
if accepted, do the work - which is not inconsiderable).

Summary of ConfigObj
================

ConfigObj is a Python 2.2 compatible config file parser. It's major
feature is simplicity of use.

It reads (and writes) INI file like config files and presents the
members using a dictionary interface.

The order of keys/sections is preserved, and it allows nested
subsections to any level :

e.g. ::

    key = value
        [section]
        key = value
          [[sub-section]]
          key = value

It is fully documented with a barrage of doctests.
All comments in the config file are also preserved as attributes of the
object, and will be written back out. This can be useful for including
comments in programatically generated config files.

It is integrated with a powerful validation system.

Difficulties & Differences
=================

A ConfigObj instance is a sub-class of the dictionary datatpe. This
means that the ``get`` method of ConfigParser clashes.

ConfigObj allows values in the root section (why not ?).

ConfigObj doesn't support line continuations (it does all multi-line
values through the use of triple quoted strings).

ConfigObj currently only allows '=' as a valid divider.

Creating ConfigParser (and related classes) compatibility is a big job.

Solution
=====

All of these problems (if deemed necessary) can be resolved. Either
through options, or just by extending the ConfigObj API. I'm happy to
put the work in.

Comments ?

All the best,


Fuzzyman
http://www.voidspace.org.uk/python/index.shtml