On Sep 10, 1:52 pm, geoffbache <[EMAIL PROTECTED]> wrote: > Hi all, > > I recently needed to parse a file that was perfect for ConfigParser > apart from one thing: the elements in the sections, although > definitions, could in some cases clash with each other and therefore > it was important to be able to retrieve them in the same order as they > appeared in the file. > > Unfortunately ConfigParser uses ordinary dictionaries for the section > elements and they are therefore returned in an arbitrary order. > > The only solution I found was to copy ConfigParser.py and replace all > the dictionaries with "sequential dictionaries" > which are exactly like dictionaries except that elements are returned > in the order they were inserted. > (seehttp://home.arcor.de/wolfgang.grafen/Python/Modules/seqdict/Seqdict.html) > > I wonder if there was a better way? For example, is there any hook > that could modify what is created by the statement > > x = {} > > I tried setting > > __builtins__.dict = ndict.seqdict > > But that didn't seem to have any effect on the above statement. > > As a secondary question, I find sequential dictionaries to be an > essential part of programming in Python and I use them all the time. I > wondered a bit if there were any plans or proposals to include them as > part of the Python library? > > Regards, > Geoff Bache
Have a look at this: http://www.python.org/dev/peps/pep-0372/ Looking at the config parser module, it looks like there are only a couple of places where {} is used. I would create a mixin class to replace the offending methods. That should work because it looks like you only have to replace "__init__" and "add_section". So... class OrderedConfigParserMixin: def __init__(self, defaults=None): self._sections = ndict.seqdict() self._defaults = ndict.seqdict() if defaults: for key, value in defaults.items(): self._defaults[self.optionxform(key)] = value def add_section(self, section): """Create a new section in the configuration. Raise DuplicateSectionError if a section by the specified name already exists. """ if section in self._sections: raise DuplicateSectionError(section) self._sections[section] = ndict.seqdict() # Then you can use this to create your own ordered config parsers. Note that # multiple inheritance in python uses a breadth first search. If you want # the methods on your mixin to get called instead of the methods on the # original class you must include the mixin first. from ConfigParser import RawConfigParser, ConfigParser, SafeConfigParser class OrderedRawConfigParser(OrderedConfigParserMixin, RawConfigParser): pass class OrderedConfigParser(OrderedConfigParserMixin, ConfigParser): pass class OrderedSafeConfigParser(OrderedConfigParserMixin, SafeConfigParser): pass I don't know if this is the _best_ approach, but it is certainly much preferred over monkey patching the built-ins module. Note that I haven't tested any of the above code. Matt -- http://mail.python.org/mailman/listinfo/python-list
