8
  #   ›ˆl–Ðz¾”êe¶¥ ´ …p\m¥1hßê„mÏÁè ?÷     ›"""Access and/or modify INI files

* Compatiable with ConfigParser
* Preserves order of sections & options
* Preserves comments/blank lines/etc
* More conveninet access to data

Example:

    >>> from StringIO import StringIO
    >>> sio = StringIO('''# configure foo-application
    ... [foo]
    ... bar1 = qualia
    ... bar2 = 1977
    ... [foo-ext]
    ... special = 1''')

    >>> cfg = INIConfig(sio)
    >>> print cfg.foo.bar1
    qualia
    >>> print cfg['foo-ext'].special
    1
    >>> cfg.foo.newopt = 'hi!'
    >>> cfg.baz.enabled = 0

    >>> print cfg
    # configure foo-application
    [foo]
    bar1 = qualia
    bar2 = 1977
    newopt = hi!
    [foo-ext]
    special = 1
    <BLANKLINE>
    [baz]
    enabled = 0

"""

# An ini parser that supports ordered sections/options
# Also supports updates, while preserving structure
# Backward-compatiable with ConfigParser

import re
from ConfigParser import DEFAULTSECT, ParsingError, MissingSectionHeaderError

import config

class LineType(object):
    line = None

    def __init__(self, line=None):
        if line is not None:
            self.line = line.strip('\n')

    # Return the original line for unmodified objects
    # Otherwise construct using the current attribute values
    def __str__(self):
        if self.line is not None:
            return self.line
        else:
            return self.to_string()

    # If an attribute is modified after initialization
    # set line to None since it is no longer accurate.
    def __setattr__(self, name, value):
        if hasattr(self,name):
            self.__dict__['line'] = None
        self.__dict__[name] = value

    def to_string(self):
        raise Exception('This method must be overridden in derived classes')


class SectionLine(LineType):
    regex =  re.compile(r'^\['
                        r'(?P<name>[^]]+)'
                        r'\]\s*'
                        r'((?P<csep>;|#)(?P<comment>.*))?$')

    def __init__(self, name, comment=None, comment_separator=None,
                             comment_offset=-1, line=None):
        super(SectionLine, self).__init__(line)
        self.name = name
        self.comment = comment
        self.comment_separator = comment_separator
        self.comment_offset = comment_offset

    def to_string(self):
        out = '[' + self.name + ']'
        if self.comment is not None:
            # try to preserve indentation of comments
            out = (out+' ').ljust(self.comment_offset)
            out = out + self.comment_separator + self.comment
        return out

    def parse(cls, line):
        m = cls.regex.match(line.rstrip())
        if m is None:
            return None
        return cls(m.group('name'), m.group('comment'),
                   m.group('csep'), m.start('csep'),
                   line)
    parse = classmethod(parse)


class OptionLine(LineType):
    def __init__(self, name, value, separator=' = ', comment=None,
                 comment_separator=None, comment_offset=-1, line=None):
        super(OptionLine, self).__init__(line)
        self.name = name
        self.value = value
        self.separator = separator
        self.comment = comment
        self.comment_separator = comment_separator
        self.comment_offset = comment_offset

    def to_string(self):
        out = '%s%s%s' % (self.name, self.separator, self.value)
        if self.comment is not None:
            # try to preserve indentation of comments
            out = (out+' ').ljust(self.comment_offset)
            out = out + self.comment_separator + self.comment
        return out

    regex = re.compile(r'^(?P<name>[^:=\s[][^:=]*)'
                       r'(?P<sep>[:=]\s*)'
                       r'(?P<value>.*)$')

    def parse(cls, line):
        m = cls.regex.match(line.rstrip())
        if m is None:
            return None

        name = m.group('name').rstrip()
        value = m.group('value')
        sep = m.group('name')[len(name):] + m.group('sep')

        # comments are not detected in the regex because