# configobj.py
# A config file reader/writer that supports nested sections in config files.
# Copyright (C) 2005-2006 Michael Foord, Nicola Larosa
# E-mail: fuzzyman AT voidspace DOT org DOT uk
#         nico AT tekNico DOT net

# ConfigObj 4
# http://www.voidspace.org.uk/python/configobj.html

# Released subject to the BSD License
# Please see http://www.voidspace.org.uk/python/license.shtml

# Scripts maintained at http://www.voidspace.org.uk/python/index.shtml
# For information about bugfixes, updates and support, please join the
# ConfigObj mailing list:
# http://lists.sourceforge.net/lists/listinfo/configobj-develop
# Comments, suggestions and bug reports welcome.

from __future__ import generators

import sys
INTP_VER = sys.version_info[:2]
if INTP_VER < (2, 2):
    raise RuntimeError("Python v.2.2 or later needed")

import os, re
import compiler
from types import StringTypes
from warnings import warn
from codecs import BOM_UTF8, BOM_UTF16, BOM_UTF16_BE, BOM_UTF16_LE

# A dictionary mapping BOM to
# the encoding to decode with, and what to set the
# encoding attribute to.
BOMS = {
    BOM_UTF8: ('utf_8', None),
    BOM_UTF16_BE: ('utf16_be', 'utf_16'),
    BOM_UTF16_LE: ('utf16_le', 'utf_16'),
    BOM_UTF16: ('utf_16', 'utf_16'),
    }
# All legal variants of the BOM codecs.
# TODO: the list of aliases is not meant to be exhaustive, is there a
#   better way ?
BOM_LIST = {
    'utf_16': 'utf_16',
    'u16': 'utf_16',
    'utf16': 'utf_16',
    'utf-16': 'utf_16',
    'utf16_be': 'utf16_be',
    'utf_16_be': 'utf16_be',
    'utf-16be': 'utf16_be',
    'utf16_le': 'utf16_le',
    'utf_16_le': 'utf16_le',
    'utf-16le': 'utf16_le',
    'utf_8': 'utf_8',
    'u8': 'utf_8',
    'utf': 'utf_8',
    'utf8': 'utf_8',
    'utf-8': 'utf_8',
    }

# Map of encodings to the BOM to write.
BOM_SET = {
    'utf_8': BOM_UTF8,
    'utf_16': BOM_UTF16,
    'utf16_be': BOM_UTF16_BE,
    'utf16_le': BOM_UTF16_LE,
    None: BOM_UTF8
    }

try:
    from validate import VdtMissingValue
except ImportError:
    VdtMissingValue = None

try:
    enumerate
except NameError:
    def enumerate(obj):
        """enumerate for Python 2.2."""
        i = -1
        for item in obj:
            i += 1
            yield i, item

try:
    True, False
except NameError:
    True, False = 1, 0


__version__ = '4.3.2'

__revision__ = '$Id: configobj.py 156 2006-01-31 14:57:08Z fuzzyman $'

__docformat__ = "restructuredtext en"

# NOTE: Does it make sense to have the following in __all__ ?
# NOTE: DEFAULT_INDENT_TYPE, NUM_INDENT_SPACES, MAX_INTERPOL_DEPTH
# NOTE: If used via ``from configobj import...``
# NOTE: They are effectively read only
__all__ = (
    '__version__',
    'DEFAULT_INDENT_TYPE',
    'NUM_INDENT_SPACES',
    'MAX_INTERPOL_DEPTH',
    'ConfigObjError',
    'NestingError',
    'ParseError',
    'DuplicateError',
    'ConfigspecError',
    'ConfigObj',
    'SimpleVal',
    'InterpolationError',
    'InterpolationDepthError',
    'MissingInterpolationOption',
    'RepeatSectionError',
    'UnreprError',
    'UnknownType',
    '__docformat__',
    'flatten_errors',
)

DEFAULT_INDENT_TYPE = ' '
NUM_INDENT_SPACES = 4
MAX_INTERPOL_DEPTH = 10

OPTION_DEFAULTS = {
    'interpolation': True,
    'raise_errors': False,
    'list_values': True,
    'create_empty': False,
    'file_error': False,
    'configspec': None,
    'stringify': True,
    # option may be set to one of ('', ' ', '\t')
    'indent_type': None,
    'encoding': None,
    'default_encoding': None,
    'unrepr': False,
    'write_empty_values': False,
}


def getObj(s):
    s = "a=" + s
    p = compiler.parse(s)
    return p.getChildren()[1].getChildren()[0].getChildren()[1]

class UnknownType(Exception):
    pass

class Builder:
    
    def build(self, o):
        m = getattr(self, 'build_' + o.__class__.__name__, None)
        if m is None:
            raise UnknownType(o.__class__.__name__)
        return m(o)
    
    def build_List(self, o):
        return map(self.build, o.getChildren())
    
    def build_Const(self, o):
        return o.value
    
    def build_Dict(self, o):
        d = {}
        i = iter(map(self.build, o.getChildren()))
        for el in i:
            d[el] = i.next()
        return d
    
    def build_Tuple(self, o):
        return tuple(self.build_List(o))
    
    def build_Name(self, o):
        if o.name == 'None':
            return None
        if o.name == 'True':
            return True
        if o.name == 'False':
            return False
        
        # An undefinted Name
        raise UnknownType('Undefined Name')
    
    def build_Add(self, o):
        real, imag = map(self.build_Const, o.getChildren())
        try:
            real = float(real)
        except TypeError:
            raise UnknownType('Add')
        if not isinstance(imag, complex) or imag.real != 0.0:
            raise UnknownType('Add')
        return real+imag
    
    def build_Getattr(self, o):
        parent = self.build(o.expr)
        return getattr(parent, o.attrname)
    
    def build_UnarySub(self, o):
        return -self.build_Const(o.getChildren()[0])
    
    def build_UnaryAdd(self, o):
        return self.build_Const(o.getChildren()[0])

def unrepr(s):
    if not s:
        return s
    return Builder().build(getObj(s))

def _splitlines(instring):
    """Split a string on lines, without losing line endings or truncating."""
    

class ConfigObjError(SyntaxError):
    """
    This is the base class for all errors that ConfigObj raises.
    It is a subclass of SyntaxError.
    """
    def __init__(self, message='', line_number=None, line=''):
        self.line = line
        self.line_number = line_number
        self.message = message
        SyntaxError.__init__(self, message)

class NestingError(ConfigObjError):
    """
    This error indicates a level of nesting that doesn't match.
    """

class ParseError(ConfigObjError):
    """
    This error indicates that a line is badly written.
    It is neither a valid ``key = value`` line,
    nor a valid section marker line.
    """

class DuplicateError(ConfigObjError):
    """
    The keyword or section specified already exists.
    """

class ConfigspecError(ConfigObjError):
    """
    An error occured whilst parsing a configspec.
    """

class InterpolationError(ConfigObjError):
    """Base class for the two interpolation errors."""

class InterpolationDepthError(InterpolationError):
    """Maximum interpolation depth exceeded in string interpolation."""

    def __init__(self, option):
        InterpolationError.__init__(
            self,
            'max interpolation depth exceeded in value "%s".' % option)

class RepeatSectionError(ConfigObjError):
    """
    This error indicates additional sections in a section with a
    ``__many__`` (repeated) section.
    """

class MissingInterpolationOption(InterpolationError):
    """A value specified for interpolation was missing."""

    def __init__(self, option):
        InterpolationError.__init__(
            self,
            'missing option "%s" in interpolation.' % option)

class UnreprError(ConfigObjError):
    """An error parsing in unrepr mode."""


class Section(dict):
    """
    A dictionary-like object that represents a section in a config file.
    
    It does string interpolation if the 'interpolate' attribute
    of the 'main' object is set to True.
    
    Interpolation is tried first from the 'DEFAULT' section of this object,
    next from the 'DEFAULT' section of the parent, lastly the main object.
    
    A Section will behave like an ordered dictionary - following the
    order of the ``scalars`` and ``sections`` attributes.
    You can use this to change the order of members.
    
    Iteration follows the order: scalars, then sections.
    """

    _KEYCRE = re.compile(r"%\(([^)]*)\)s|.")

    def __init__(self, parent, depth, main, indict=None, name=None):
        """
        * parent is the section above
        * depth is the depth level of this section
        * main is the main ConfigObj
        * indict is a dictionary to initialise the section with
        """
        if indict is None:
            indict = {}
        dict.__init__(self)
        # used for nesting level *and* interpolation
        self.parent = parent
        # used for the interpolation attribute
        self.main = main
        # level of nesting depth of this Section
        self.depth = depth
        # the sequence of scalar values in this Section
        self.scalars = []
        # the sequence of sections in this Section
        self.sections = []
        # purely for information
        self.name = name
        # for comments :-)
        self.comments = {}
        self.inline_comments = {}
        # for the configspec
        self.configspec = {}
        self._order = []
        self._configspec_comments = {}
        self._configspec_inline_comments = {}
        self._cs_section_comments = {}
        self._cs_section_inline_comments = {}
        # for defaults
        self.defaults = []
        #
        # we do this explicitly so that __setitem__ is used properly
        # (rather than just passing to ``dict.__init__``)
        for entry in indict:
            self[entry] = indict[entry]

    def _interpolate(self, value):
        """Nicked from ConfigParser."""
        depth = MAX_INTERPOL_DEPTH
        # loop through this until it's done
        while depth:
            depth -= 1
            if value.find("%(") != -1:
                value = self._KEYCRE.sub(self._interpolation_replace, value)
            else:
                break
        else:
            raise InterpolationDepthError(value)
        return value

    def _interpolation_replace(self, match):
        """ """
        s = match.group(1)
        if s is None:
            return match.group()
        else:
            # switch off interpolation before we try and fetch anything !
            self.main.interpolation = False
            # try the 'DEFAULT' member of *this section* first
            val = self.get('DEFAULT', {}).get(s)
            # try the 'DEFAULT' member of the *parent section* next
            if val is None:
                val = self.parent.get('DEFAULT', {}).get(s)
            # last, try the 'DEFAULT' member of the *main section*
            if val is None:
                val = self.main.get('DEFAULT', {}).get(s)
            self.main.interpolation = True
            if val is None:
                raise MissingInterpolationOption(s)
            return val

    def __getitem__(self, key):
        """Fetch the item and do string interpolation."""
        val = dict.__getitem__(self, key)
        if self.main.interpolation and isinstance(val, StringTypes):
            return self._interpolate(val)
        return val

    def __setitem__(self, key, value, unrepr=False):
        """
        Correctly set a value.
        
        Making dictionary values Section instances.
        (We have to special case 'Section' instances - which are also dicts)
        
        Keys must be strings.
        Values need only be strings (or lists of strings) if
        ``main.stringify`` is set.
        
        `unrepr`` must be set when setting a value to a dictionary, without
        creating a new sub-section.
        """
        if not isinstance(key, StringTypes):
            raise ValueError, 'The key "%s" is not a string.' % key
        # add the comment
        if not self.comments.has_key(key):
            self.comments[key] = []
            self.inline_comments[key] = ''
        # remove the entry from defaults
        if key in self.defaults:
            self.defaults.remove(key)
        #
        if isinstance(value, Section):
            if not self.has_key(key):
                self.sections.append(key)
            dict.__setitem__(self, key, value)
        elif isinstance(value, dict) and not unrepr:
            # First create the new depth level,
            # then create the section
            if not self.has_key(key):
                self.sections.append(key)
            new_depth = self.depth + 1
            dict.__setitem__(
                self,
                key,
                Section(
                    self,
                    new_depth,
                    self.main,
                    indict=value,
                    name=key))
        else:
            if not self.has_key(key):
                self.scalars.append(key)
            if not self.main.stringify:
                if isinstance(value, StringTypes):
                    pass
                elif isinstance(value, (list, tuple)):
                    for entry in value:
                        if not isinstance(entry, StringTypes):
                            raise TypeError, (
                                'Value is not a string "%s".' % entry)
                else:
                    raise TypeError, 'Value is not a string "%s".' % value
            dict.__setitem__(self, key, value)

    def __delitem__(self, key):
        """Remove items from the sequence when deleting."""
        dict. __delitem__(self, key)
        if key in self.scalars:
            self.scalars.remove(key)
        else:
            self.sections.remove(key)
        del self.comments[key]
        del self.inline_comments[key]

    def get(self, key, default=None):
        """A version of ``get`` that doesn't bypass string interpolation."""
        try:
            return self[key]
        except KeyError:
            return default

    def update(self, indict):
        """
        A version of update that uses our ``__setitem__``.
        """
        for entry in indict:
            self[entry] = indict[entry]

    def pop(self, key, *args):
        """ """
        val = dict.pop(self, key, *args)
        if key in self.scalars:
            del self.comments[key]
            del self.inline_comments[key]
            self.scalars.remove(key)
        elif key in self.sections:
            del self.comments[key]
            del self.inline_comments[key]
            self.sections.remove(key)
        if self.main.interpolation and isinstance(val, StringTypes):
            return self._interpolate(val)
        return val

    def popitem(self):
        """Pops the first (key,val)"""
        sequence = (self.scalars + self.sections)
        if not sequence:
            raise KeyError, ": 'popitem(): dictionary is empty'"
        key = sequence[0]
        val =  self[key]
        del self[key]
        return key, val

    def clear(self):
        """
        A version of clear that also affects scalars/sections
        Also clears comments and configspec.
        
        Leaves other attributes alone :
            depth/main/parent are not affected
        """
        dict.clear(self)
        self.scalars = []
        self.sections = []
        self.comments = {}
        self.inline_comments = {}
        self.configspec = {}

    def setdefault(self, key, default=None):
        """A version of setdefault that sets sequence if appropriate."""
        try:
            return self[key]
        except KeyError:
            self[key] = default
            return self[key]

    def items(self):
        """ """
        return zip((self.scalars + self.sections), self.values())

    def keys(self):
        """ """
        return (self.scalars + self.sections)

    def values(self):
        """ """
        return [self[key] for key in (self.scalars + self.sections)]

    def iteritems(self):
        """ """
        return iter(self.items())

    def iterkeys(self):
        """ """
        return iter((self.scalars + self.sections))

    __iter__ = iterkeys

    def itervalues(self):
        """ """
        return iter(self.values())

    def __repr__(self):
        return '{%s}' % ', '.join([('%s: %s' % (repr(key), repr(self[key])))
            for key in (self.scalars + self.sections)])

    __str__ = __repr__

    # Extra methods - not in a normal dictionary

    def dict(self):
        """
        Return a deepcopy of self as a dictionary.
        
        All members that are ``Section`` instances are recursively turned to
        ordinary dictionaries - by calling their ``dict`` method.
        
        >>> n = a.dict()
        >>> n == a
        1
        >>> n is a
        0
        """
        newdict = {}
        for entry in self:
            this_entry = self[entry]
            if isinstance(this_entry, Section):
                this_entry = this_entry.dict()
            elif isinstance(this_entry, list):
                # create a copy rather than a reference
                this_entry = list(this_entry)
            elif isinstance(this_entry, tuple):
                # create a copy rather than a reference
                this_entry = tuple(this_entry)
            newdict[entry] = this_entry
        return newdict

    def merge(self, indict):
        """
        A recursive update - useful for merging config files.
        
        >>> a = '''[section1]
        ...     option1 = True
        ...     [[subsection]]
        ...     more_options = False
        ...     # end of file'''.splitlines()
        >>> b = '''# File is user.ini
        ...     [section1]
        ...     option1 = False
        ...     # end of file'''.splitlines()
        >>> c1 = ConfigObj(b)
        >>> c2 = ConfigObj(a)
        >>> c2.merge(c1)
        >>> c2
        {'section1': {'option1': 'False', 'subsection': {'more_options': 'False'}}}
        """
        for key, val in indict.items():
            if (key in self and isinstance(self[key], dict) and
                                isinstance(val, dict)):
                self[key].merge(val)
            else:   
                self[key] = val

    def rename(self, oldkey, newkey):
        """
        Change a keyname to another, without changing position in sequence.
        
        Implemented so that transformations can be made on keys,
        as well as on values. (used by encode and decode)
        
        Also renames comments.
        """
        if oldkey in self.scalars:
            the_list = self.scalars
        elif oldkey in self.sections:
            the_list = self.sections
        else:
            raise KeyError, 'Key "%s" not found.' % oldkey
        pos = the_list.index(oldkey)
        #
        val = self[oldkey]
        dict.__delitem__(self, oldkey)
        dict.__setitem__(self, newkey, val)
        the_list.remove(oldkey)
        the_list.insert(pos, newkey)
        comm = self.comments[oldkey]
        inline_comment = self.inline_comments[oldkey]
        del self.comments[oldkey]
        del self.inline_comments[oldkey]
        self.comments[newkey] = comm
        self.inline_comments[newkey] = inline_comment

    def walk(self, function, raise_errors=True,
            call_on_sections=False, **keywargs):
        """
        Walk every member and call a function on the keyword and value.
        
        Return a dictionary of the return values
        
        If the function raises an exception, raise the errror
        unless ``raise_errors=False``, in which case set the return value to
        ``False``.
        
        Any unrecognised keyword arguments you pass to walk, will be pased on
        to the function you pass in.
        
        Note: if ``call_on_sections`` is ``True`` then - on encountering a
        subsection, *first* the function is called for the *whole* subsection,
        and then recurses into it's members. This means your function must be
        able to handle strings, dictionaries and lists. This allows you
        to change the key of subsections as well as for ordinary members. The
        return value when called on the whole subsection has to be discarded.
        
        See  the encode and decode methods for examples, including functions.
        
        .. caution::
        
            You can use ``walk`` to transform the names of members of a section
            but you mustn't add or delete members.
        
        >>> config = '''[XXXXsection]
        ... XXXXkey = XXXXvalue'''.splitlines()
        >>> cfg = ConfigObj(config)
        >>> cfg
        {'XXXXsection': {'XXXXkey': 'XXXXvalue'}}
        >>> def transform(section, key):
        ...     val = section[key]
        ...     newkey = key.replace('XXXX', 'CLIENT1')
        ...     section.rename(key, newkey)
        ...     if isinstance(val, (tuple, list, dict)):
        ...         pass
        ...     else:
        ...         val = val.replace('XXXX', 'CLIENT1')
        ...         section[newkey] = val
        >>> cfg.walk(transform, call_on_sections=True)
        {'CLIENT1section': {'CLIENT1key': None}}
        >>> cfg
        {'CLIENT1section': {'CLIENT1key': 'CLIENT1value'}}
        """
        out = {}
        # scalars first
        for i in range(len(self.scalars)):
            entry = self.scalars[i]
            try:
                val = function(self, entry, **keywargs)
                # bound again in case name has changed
                entry = self.scalars[i]
                out[entry] = val
            except Exception:
                if raise_errors:
                    raise
                else:
                    entry = self.scalars[i]
                    out[entry] = False
        # then sections
        for i in range(len(self.sections)):
            entry = self.sections[i]
            if call_on_sections:
                try:
                    function(self, entry, **keywargs)
                except Exception:
                    if raise_errors:
                        raise
                    else:
                        entry = self.sections[i]
                        out[entry] = False
                # bound again in case name has changed
                entry = self.sections[i]
            # previous result is discarded
            out[entry] = self[entry].walk(
                function,
                raise_errors=raise_errors,
                call_on_sections=call_on_sections,
                **keywargs)
        return out

    def decode(self, encoding):
        """
        Decode all strings and values to unicode, using the specified encoding.
        
        Works with subsections and list values.
        
        Uses the ``walk`` method.
        
        Testing ``encode`` and ``decode``.
        >>> m = ConfigObj(a)
        >>> m.decode('ascii')
        >>> def testuni(val):
        ...     for entry in val:
        ...         if not isinstance(entry, unicode):
        ...             print >> sys.stderr, type(entry)
        ...             raise AssertionError, 'decode failed.'
        ...         if isinstance(val[entry], dict):
        ...             testuni(val[entry])
        ...         elif not isinstance(val[entry], unicode):
        ...             raise AssertionError, 'decode failed.'
        >>> testuni(m)
        >>> m.encode('ascii')
        >>> a == m
        1
        """
        warn('use of ``decode`` is deprecated.', DeprecationWarning)
        def decode(section, key, encoding=encoding, warn=True):
            """ """
            val = section[key]
            if isinstance(val, (list, tuple)):
                newval = []
                for entry in val:
                    newval.append(entry.decode(encoding))
            elif isinstance(val, dict):
                newval = val
            else:
                newval = val.decode(encoding)
            newkey = key.decode(encoding)
            section.rename(key, newkey)
            section[newkey] = newval
        # using ``call_on_sections`` allows us to modify section names
        self.walk(decode, call_on_sections=True)

    def encode(self, encoding):
        """
        Encode all strings and values from unicode,
        using the specified encoding.
        
        Works with subsections and list values.
        Uses the ``walk`` method.
        """
        warn('use of ``encode`` is deprecated.', DeprecationWarning)
        def encode(section, key, encoding=encoding):
            """ """
            val = section[key]
            if isinstance(val, (list, tuple)):
                newval = []
                for entry in val:
                    newval.append(entry.encode(encoding))
            elif isinstance(val, dict):
                newval = val
            else:
                newval = val.encode(encoding)
            newkey = key.encode(encoding)
            section.rename(key, newkey)
            section[newkey] = newval
        self.walk(encode, call_on_sections=True)

    def istrue(self, key):
        """A deprecated version of ``as_bool``."""
        warn('use of ``istrue`` is deprecated. Use ``as_bool`` method '
                'instead.', DeprecationWarning)
        return self.as_bool(key)

    def as_bool(self, key):
        """
        Accepts a key as input. The corresponding value must be a string or
        the objects (``True`` or 1) or (``False`` or 0). We allow 0 and 1 to
        retain compatibility with Python 2.2.
        
        If the string is one of  ``True``, ``On``, ``Yes``, or ``1`` it returns 
        ``True``.
        
        If the string is one of  ``False``, ``Off``, ``No``, or ``0`` it returns 
        ``False``.
        
        ``as_bool`` is not case sensitive.
        
        Any other input will raise a ``ValueError``.
        
        >>> a = ConfigObj()
        >>> a['a'] = 'fish'
        >>> a.as_bool('a')
        Traceback (most recent call last):
        ValueError: Value "fish" is neither True nor False
        >>> a['b'] = 'True'
        >>> a.as_bool('b')
        1
        >>> a['b'] = 'off'
        >>> a.as_bool('b')
        0
        """
        val = self[key]
        if val == True:
            return True
        elif val == False:
            return False
        else:
            try:
                if not isinstance(val, StringTypes):
                    raise KeyError
                else:
                    return self.main._bools[val.lower()]
            except KeyError:
                raise ValueError('Value "%s" is neither True nor False' % val)

    def as_int(self, key):
        """
        A convenience method which coerces the specified value to an integer.
        
        If the value is an invalid literal for ``int``, a ``ValueError`` will
        be raised.
        
        >>> a = ConfigObj()
        >>> a['a'] = 'fish'
        >>> a.as_int('a')
        Traceback (most recent call last):
        ValueError: invalid literal for int(): fish
        >>> a['b'] = '1'
        >>> a.as_int('b')
        1
        >>> a['b'] = '3.2'
        >>> a.as_int('b')
        Traceback (most recent call last):
        ValueError: invalid literal for int(): 3.2
        """
        return int(self[key])

    def as_float(self, key):
        """
        A convenience method which coerces the specified value to a float.
        
        If the value is an invalid literal for ``float``, a ``ValueError`` will
        be raised.
        
        >>> a = ConfigObj()
        >>> a['a'] = 'fish'
        >>> a.as_float('a')
        Traceback (most recent call last):
        ValueError: invalid literal for float(): fish
        >>> a['b'] = '1'
        >>> a.as_float('b')
        1.0
        >>> a['b'] = '3.2'
        >>> a.as_float('b')
        3.2000000000000002
        """
        return float(self[key])
    

class ConfigObj(Section):
    """An object to read, create, and write config files."""

    _keyword = re.compile(r'''^ # line start
        (\s*)                   # indentation
        (                       # keyword
            (?:".*?")|          # double quotes
            (?:'.*?')|          # single quotes
            (?:[^'"=].*?)       # no quotes
        )
        \s*=\s*                 # divider
        (.*)                    # value (including list values and comments)
        $   # line end
        ''',
        re.VERBOSE)

    _sectionmarker = re.compile(r'''^
        (\s*)                     # 1: indentation
        ((?:\[\s*)+)              # 2: section marker open
        (                         # 3: section name open
            (?:"\s*\S.*?\s*")|    # at least one non-space with double quotes
            (?:'\s*\S.*?\s*')|    # at least one non-space with single quotes
            (?:[^'"\s].*?)        # at least one non-space unquoted
        )                         # section name close
        ((?:\s*\])+)              # 4: section marker close
        \s*(\#.*)?                # 5: optional comment
        $''',
        re.VERBOSE)

    # this regexp pulls list values out as a single string
    # or single values and comments
    # FIXME: this regex adds a '' to the end of comma terminated lists
    #   workaround in ``_handle_value``
    _valueexp = re.compile(r'''^
        (?:
            (?:
                (
                    (?:
                        (?:
                            (?:".*?")|              # double quotes
                            (?:'.*?')|              # single quotes
                            (?:[^'",\#][^,\#]*?)    # unquoted
                        )
                        \s*,\s*                     # comma
                    )*      # match all list items ending in a comma (if any)
                )
                (
                    (?:".*?")|                      # double quotes
                    (?:'.*?')|                      # single quotes
                    (?:[^'",\#\s][^,]*?)|           # unquoted
                    (?:(?<!,))                      # Empty value
                )?          # last item in a list - or string value
            )|
            (,)             # alternatively a single comma - empty list
        )
        \s*(\#.*)?          # optional comment
        $''',
        re.VERBOSE)

    # use findall to get the members of a list value
    _listvalueexp = re.compile(r'''
        (
            (?:".*?")|          # double quotes
            (?:'.*?')|          # single quotes
            (?:[^'",\#].*?)       # unquoted
        )
        \s*,\s*                 # comma
        ''',
        re.VERBOSE)

    # this regexp is used for the value
    # when lists are switched off
    _nolistvalue = re.compile(r'''^
        (
            (?:".*?")|          # double quotes
            (?:'.*?')|          # single quotes
            (?:[^'"\#].*?)|     # unquoted
            (?:)                # Empty value
        )
        \s*(\#.*)?              # optional comment
        $''',
        re.VERBOSE)

    # regexes for finding triple quoted values on one line
    _single_line_single = re.compile(r"^'''(.*?)'''\s*(#.*)?$")
    _single_line_double = re.compile(r'^"""(.*?)"""\s*(#.*)?$')
    _multi_line_single = re.compile(r"^(.*?)'''\s*(#.*)?$")
    _multi_line_double = re.compile(r'^(.*?)"""\s*(#.*)?$')

    _triple_quote = {
        "'''": (_single_line_single, _multi_line_single),
        '"""': (_single_line_double, _multi_line_double),
    }

    # Used by the ``istrue`` Section method
    _bools = {
        'yes': True, 'no': False,
        'on': True, 'off': False,
        '1': True, '0': False,
        'true': True, 'false': False,
        }

    def __init__(self, infile=None, options=None, **kwargs):
        """
        Parse or create a config file object.
        
        ``ConfigObj(infile=None, options=None, **kwargs)``
        """
        if infile is None:
            infile = []
        if options is None:
            options = {}
        else:
            options = dict(options)
        # keyword arguments take precedence over an options dictionary
        options.update(kwargs)
        # init the superclass
        Section.__init__(self, self, 0, self)
        #
        defaults = OPTION_DEFAULTS.copy()
        for entry in options.keys():
            if entry not in defaults.keys():
                raise TypeError, 'Unrecognised option "%s".' % entry
        # TODO: check the values too.
        #
        # Add any explicit options to the defaults
        defaults.update(options)
        #
        # initialise a few variables
        self.filename = None
        self._errors = []
        self.raise_errors = defaults['raise_errors']
        self.interpolation = defaults['interpolation']
        self.list_values = defaults['list_values']
        self.create_empty = defaults['create_empty']
        self.file_error = defaults['file_error']
        self.stringify = defaults['stringify']
        self.indent_type = defaults['indent_type']
        self.encoding = defaults['encoding']
        self.default_encoding = defaults['default_encoding']
        self.BOM = False
        self.newlines = None
        self.write_empty_values = defaults['write_empty_values']
        self.unrepr = defaults['unrepr']
        #
        self.initial_comment = []
        self.final_comment = []
        #
        self._terminated = False
        #
        if isinstance(infile, StringTypes):
            self.filename = infile
            if os.path.isfile(infile):
                infile = open(infile).read() or []
            elif self.file_error:
                # raise an error if the file doesn't exist
                raise IOError, 'Config file not found: "%s".' % self.filename
            else:
                # file doesn't already exist
                if self.create_empty:
                    # this is a good test that the filename specified
                    # isn't impossible - like on a non existent device
                    h = open(infile, 'w')
                    h.write('')
                    h.close()
                infile = []
        elif isinstance(infile, (list, tuple)):
            infile = list(infile)
        elif isinstance(infile, dict):
            # initialise self
            # the Section class handles creating subsections
            if isinstance(infile, ConfigObj):
                # get a copy of our ConfigObj
                infile = infile.dict()
            for entry in infile:
                self[entry] = infile[entry]
            del self._errors
            if defaults['configspec'] is not None:
                self._handle_configspec(defaults['configspec'])
            else:
                self.configspec = None
            return
        elif hasattr(infile, 'read'):
            # This supports file like objects
            infile = infile.read() or []
            # needs splitting into lines - but needs doing *after* decoding
            # in case it's not an 8 bit encoding
        else:
            raise TypeError, ('infile must be a filename,'
                ' file like object, or list of lines.')
        #
        if infile:
            # don't do it for the empty ConfigObj
            infile = self._handle_bom(infile)
            # infile is now *always* a list
            #
            # Set the newlines attribute (first line ending it finds)
            # and strip trailing '\n' or '\r' from lines
            for line in infile:
                if (not line) or (line[-1] not in '\r\n'):
                    continue
                for end in ('\r\n', '\n', '\r'):
                    if line.endswith(end):
                        self.newlines = end
                        break
                break
            if infile[-1] and infile[-1] in '\r\n':
                self._terminated = True
            infile = [line.rstrip('\r\n') for line in infile]
        #
        self._parse(infile)
        # if we had any errors, now is the time to raise them
        if self._errors:
            info = "at line %s." % self._errors[0].line_number
            if len(self._errors) > 1:
                msg = ("Parsing failed with several errors.\nFirst error %s" %
                    info)
                error = ConfigObjError(msg)
            else:
                error = self._errors[0]
            # set the errors attribute; it's a list of tuples:
            # (error_type, message, line_number)
            error.errors = self._errors
            # set the config attribute
            error.config = self
            raise error
        # delete private attributes
        del self._errors
        #
        if defaults['configspec'] is None:
            self.configspec = None
        else:
            self._handle_configspec(defaults['configspec'])
    
    def __repr__(self):
        return 'ConfigObj({%s})' % ', '.join(
            [('%s: %s' % (repr(key), repr(self[key]))) for key in
            (self.scalars + self.sections)])
    
    def _handle_bom(self, infile):
        """
        Handle any BOM, and decode if necessary.
        
        If an encoding is specified, that *must* be used - but the BOM should
        still be removed (and the BOM attribute set).
        
        (If the encoding is wrongly specified, then a BOM for an alternative
        encoding won't be discovered or removed.)
        
        If an encoding is not specified, UTF8 or UTF16 BOM will be detected and
        removed. The BOM attribute will be set. UTF16 will be decoded to
        unicode.
        
        NOTE: This method must not be called with an empty ``infile``.
        
        Specifying the *wrong* encoding is likely to cause a
        ``UnicodeDecodeError``.
        
        ``infile`` must always be returned as a list of lines, but may be
        passed in as a single string.
        """
        if ((self.encoding is not None) and
            (self.encoding.lower() not in BOM_LIST)):
            # No need to check for a BOM
            # the encoding specified doesn't have one
            # just decode
            return self._decode(infile, self.encoding)
        #
        if isinstance(infile, (list, tuple)):
            line = infile[0]
        else:
            line = infile
        if self.encoding is not None:
            # encoding explicitly supplied
            # And it could have an associated BOM
            # TODO: if encoding is just UTF16 - we ought to check for both
            # TODO: big endian and little endian versions.
            enc = BOM_LIST[self.encoding.lower()]
            if enc == 'utf_16':
                # For UTF16 we try big endian and little endian
                for BOM, (encoding, final_encoding) in BOMS.items():
                    if not final_encoding:
                        # skip UTF8
                        continue
                    if infile.startswith(BOM):
                        ### BOM discovered
                        ##self.BOM = True
                        # Don't need to remove BOM
                        return self._decode(infile, encoding)
                #
                # If we get this far, will *probably* raise a DecodeError
                # As it doesn't appear to start with a BOM
                return self._decode(infile, self.encoding)
            #
            # Must be UTF8
            BOM = BOM_SET[enc]
            if not line.startswith(BOM):
                return self._decode(infile, self.encoding)
            #
            newline = line[len(BOM):]
            #
            # BOM removed
            if isinstance(infile, (list, tuple)):
                infile[0] = newline
            else:
                infile = newline
            self.BOM = True
            return self._decode(infile, self.encoding)
        #
        # No encoding specified - so we need to check for UTF8/UTF16
        for BOM, (encoding, final_encoding) in BOMS.items():
            if not line.startswith(BOM):
                continue
            else:
                # BOM discovered
                self.encoding = final_encoding
                if not final_encoding:
                    self.BOM = True
                    # UTF8
                    # remove BOM
                    newline = line[len(BOM):]
                    if isinstance(infile, (list, tuple)):
                        infile[0] = newline
                    else:
                        infile = newline
                    # UTF8 - don't decode
                    if isinstance(infile, StringTypes):
                        return infile.splitlines(True)
                    else:
                        return infile
                # UTF16 - have to decode
                return self._decode(infile, encoding)
        #
        # No BOM discovered and no encoding specified, just return
        if isinstance(infile, StringTypes):
            # infile read from a file will be a single string
            return infile.splitlines(True)
        else:
            return infile

    def _a_to_u(self, string):
        """Decode ascii strings to unicode if a self.encoding is specified."""
        if not self.encoding:
            return string
        else:
            return string.decode('ascii')

    def _decode(self, infile, encoding):
        """
        Decode infile to unicode. Using the specified encoding.
        
        if is a string, it also needs converting to a list.
        """
        if isinstance(infile, StringTypes):
            # can't be unicode
            # NOTE: Could raise a ``UnicodeDecodeError``
            return infile.decode(encoding).splitlines(True)
        for i, line in enumerate(infile):
            if not isinstance(line, unicode):
                # NOTE: The isinstance test here handles mixed lists of unicode/string
                # NOTE: But the decode will break on any non-string values
                # NOTE: Or could raise a ``UnicodeDecodeError``
                infile[i] = line.decode(encoding)
        return infile

    def _decode_element(self, line):
        """Decode element to unicode if necessary."""
        if not self.encoding:
            return line
        if isinstance(line, str) and self.default_encoding:
            return line.decode(self.default_encoding)
        return line

    def _str(self, value):
        """
        Used by ``stringify`` within validate, to turn non-string values
        into strings.
        """
        if not isinstance(value, StringTypes):
            return str(value)
        else:
            return value

    def _parse(self, infile):
        """Actually parse the config file."""
        temp_list_values = self.list_values
        if self.unrepr:
            self.list_values = False
        comment_list = []
        done_start = False
        this_section = self
        maxline = len(infile) - 1
        cur_index = -1
        reset_comment = False
        while cur_index < maxline:
            if reset_comment:
                comment_list = []
            cur_index += 1
            line = infile[cur_index]
            sline = line.strip()
            # do we have anything on the line ?
            if not sline or sline.startswith('#'):
                reset_comment = False
                comment_list.append(line)
                continue
            if not done_start:
                # preserve initial comment
                self.initial_comment = comment_list
                comment_list = []
                done_start = True
            reset_comment = True
            # first we check if it's a section marker
            mat = self._sectionmarker.match(line)
            if mat is not None:
                # is a section line
                (indent, sect_open, sect_name, sect_close, comment) = (
                    mat.groups())
                if indent and (self.indent_type is None):
                    self.indent_type = indent[0]
                cur_depth = sect_open.count('[')
                if cur_depth != sect_close.count(']'):
                    self._handle_error(
                        "Cannot compute the section depth at line %s.",
                        NestingError, infile, cur_index)
                    continue
                #
                if cur_depth < this_section.depth:
                    # the new section is dropping back to a previous level
                    try:
                        parent = self._match_depth(
                            this_section,
                            cur_depth).parent
                    except SyntaxError:
                        self._handle_error(
                            "Cannot compute nesting level at line %s.",
                            NestingError, infile, cur_index)
                        continue
                elif cur_depth == this_section.depth:
                    # the new section is a sibling of the current section
                    parent = this_section.parent
                elif cur_depth == this_section.depth + 1:
                    # the new section is a child the current section
                    parent = this_section
                else:
                    self._handle_error(
                        "Section too nested at line %s.",
                        NestingError, infile, cur_index)
                #
                sect_name = self._unquote(sect_name)
                if parent.has_key(sect_name):
                    self._handle_error(
                        'Duplicate section name at line %s.',
                        DuplicateError, infile, cur_index)
                    continue
                # create the new section
                this_section = Section(
                    parent,
                    cur_depth,
                    self,
                    name=sect_name)
                parent[sect_name] = this_section
                parent.inline_comments[sect_name] = comment
                parent.comments[sect_name] = comment_list
                continue
            #
            # it's not a section marker,
            # so it should be a valid ``key = value`` line
            mat = self._keyword.match(line)
            if mat is None:
                # it neither matched as a keyword
                # or a section marker
                self._handle_error(
                    'Invalid line at line "%s".',
                    ParseError, infile, cur_index)
            else:
                # is a keyword value
                # value will include any inline comment
                (indent, key, value) = mat.groups()
                if indent and (self.indent_type is None):
                    self.indent_type = indent[0]
                # check for a multiline value
                if value[:3] in ['"""', "'''"]:
                    try:
                        (value, comment, cur_index) = self._multiline(
                            value, infile, cur_index, maxline)
                    except SyntaxError:
                        self._handle_error(
                            'Parse error in value at line %s.',
                            ParseError, infile, cur_index)
                        continue
                    else:
                        if self.unrepr:
                            comment = ''
                            try:
                                value = unrepr(value)
                            except Exception, e:
                                if type(e) == UnknownType:
                                    msg = 'Unknown name or type in value at line %s.'
                                else:
                                    msg = 'Parse error in value at line %s.'
                                self._handle_error(msg, UnreprError, infile,
                                    cur_index)
                                continue
                else:
                    if self.unrepr:
                        comment = ''
                        try:
                            value = unrepr(value)
                        except Exception, e:
                            if isinstance(e, UnknownType):
                                msg = 'Unknown name or type in value at line %s.'
                            else:
                                msg = 'Parse error in value at line %s.'
                            self._handle_error(msg, UnreprError, infile,
                                cur_index)
                            continue
                    else:
                        # extract comment and lists
                        try:
                            (value, comment) = self._handle_value(value)
                        except SyntaxError:
                            self._handle_error(
                                'Parse error in value at line %s.',
                                ParseError, infile, cur_index)
                            continue
                #
                key = self._unquote(key)
                if this_section.has_key(key):
                    self._handle_error(
                        'Duplicate keyword name at line %s.',
                        DuplicateError, infile, cur_index)
                    continue
                # add the key.
                # we set unrepr because if we have got this far we will never
                # be creating a new section
                this_section.__setitem__(key, value, unrepr=True)
                this_section.inline_comments[key] = comment
                this_section.comments[key] = comment_list
                continue
        #
        if self.indent_type is None:
            # no indentation used, set the type accordingly
            self.indent_type = ''
        #
        if self._terminated:
            comment_list.append('')
        # preserve the final comment
        if not self and not self.initial_comment:
            self.initial_comment = comment_list
        elif not reset_comment:
            self.final_comment = comment_list
        self.list_values = temp_list_values

    def _match_depth(self, sect, depth):
        """
        Given a section and a depth level, walk back through the sections
        parents to see if the depth level matches a previous section.
        
        Return a reference to the right section,
        or raise a SyntaxError.
        """
        while depth < sect.depth:
            if sect is sect.parent:
                # we've reached the top level already
                raise SyntaxError
            sect = sect.parent
        if sect.depth == depth:
            return sect
        # shouldn't get here
        raise SyntaxError

    def _handle_error(self, text, ErrorClass, infile, cur_index):
        """
        Handle an error according to the error settings.
        
        Either raise the error or store it.
        The error will have occured at ``cur_index``
        """
        line = infile[cur_index]
        cur_index += 1
        message = text % cur_index
        error = ErrorClass(message, cur_index, line)
        if self.raise_errors:
            # raise the error - parsing stops here
            raise error
        # store the error
        # reraise when parsing has finished
        self._errors.append(error)

    def _unquote(self, value):
        """Return an unquoted version of a value"""
        if (value[0] == value[-1]) and (value[0] in ('"', "'")):
            value = value[1:-1]
        return value

    def _quote(self, value, multiline=True):
        """
        Return a safely quoted version of a value.
        
        Raise a ConfigObjError if the value cannot be safely quoted.
        If multiline is ``True`` (default) then use triple quotes
        if necessary.
        
        Don't quote values that don't need it.
        Recursively quote members of a list and return a comma joined list.
        Multiline is ``False`` for lists.
        Obey list syntax for empty and single member lists.
        
        If ``list_values=False`` then the value is only quoted if it contains
        a ``\n`` (is multiline).
        
        If ``write_empty_values`` is set, and the value is an empty string, it
        won't be quoted.
        """
        if multiline and self.write_empty_values and value == '':
            # Only if multiline is set, so that it is used for values not
            # keys, and not values that are part of a list
            return ''
        if multiline and isinstance(value, (list, tuple)):
            if not value:
                return ','
            elif len(value) == 1:
                return self._quote(value[0], multiline=False) + ','
            return ', '.join([self._quote(val, multiline=False)
                for val in value])
        if not isinstance(value, StringTypes):
            if self.stringify:
                value = str(value)
            else:
                raise TypeError, 'Value "%s" is not a string.' % value
        squot = "'%s'"
        dquot = '"%s"'
        noquot = "%s"
        wspace_plus = ' \r\t\n\v\t\'"'
        tsquot = '"""%s"""'
        tdquot = "'''%s'''"
        if not value:
            return '""'
        if (not self.list_values and '\n' not in value) or not (multiline and
                ((("'" in value) and ('"' in value)) or ('\n' in value))):
            if not self.list_values:
                # we don't quote if ``list_values=False``
                quot = noquot
            # for normal values either single or double quotes will do
            elif '\n' in value:
                # will only happen if multiline is off - e.g. '\n' in key
                raise ConfigObjError, ('Value "%s" cannot be safely quoted.' %
                    value)
            elif ((value[0] not in wspace_plus) and
                    (value[-1] not in wspace_plus) and
                    (',' not in value)):
                quot = noquot
            else:
                if ("'" in value) and ('"' in value):
                    raise ConfigObjError, (
                        'Value "%s" cannot be safely quoted.' % value)
                elif '"' in value:
                    quot = squot
                else:
                    quot = dquot
        else:
            # if value has '\n' or "'" *and* '"', it will need triple quotes
            if (value.find('"""') != -1) and (value.find("'''") != -1):
                raise ConfigObjError, (
                    'Value "%s" cannot be safely quoted.' % value)
            if value.find('"""') == -1:
                quot = tdquot
            else:
                quot = tsquot
        return quot % value

    def _handle_value(self, value):
        """
        Given a value string, unquote, remove comment,
        handle lists. (including empty and single member lists)
        """
        # do we look for lists in values ?
        if not self.list_values:
            mat = self._nolistvalue.match(value)
            if mat is None:
                raise SyntaxError
            # NOTE: we don't unquote here
            return mat.groups()
        #
        mat = self._valueexp.match(value)
        if mat is None:
            # the value is badly constructed, probably badly quoted,
            # or an invalid list
            raise SyntaxError
        (list_values, single, empty_list, comment) = mat.groups()
        if (list_values == '') and (single is None):
            # change this if you want to accept empty values
            raise SyntaxError
        # NOTE: note there is no error handling from here if the regex
        # is wrong: then incorrect values will slip through
        if empty_list is not None:
            # the single comma - meaning an empty list
            return ([], comment)
        if single is not None:
            # handle empty values
            if list_values and not single:
                # FIXME: the '' is a workaround because our regex now matches
                #   '' at the end of a list if it has a trailing comma
                single = None
            else:
                single = single or '""'
                single = self._unquote(single)
        if list_values == '':
            # not a list value
            return (single, comment)
        the_list = self._listvalueexp.findall(list_values)
        the_list = [self._unquote(val) for val in the_list]
        if single is not None:
            the_list += [single]
        return (the_list, comment)

    def _multiline(self, value, infile, cur_index, maxline):
        """Extract the value, where we are in a multiline situation."""
        quot = value[:3]
        newvalue = value[3:]
        single_line = self._triple_quote[quot][0]
        multi_line = self._triple_quote[quot][1]
        mat = single_line.match(value)
        if mat is not None:
            retval = list(mat.groups())
            retval.append(cur_index)
            return retval
        elif newvalue.find(quot) != -1:
            # somehow the triple quote is missing
            raise SyntaxError
        #
        while cur_index < maxline:
            cur_index += 1
            newvalue += '\n'
            line = infile[cur_index]
            if line.find(quot) == -1:
                newvalue += line
            else:
                # end of multiline, process it
                break
        else:
            # we've got to the end of the config, oops...
            raise SyntaxError
        mat = multi_line.match(line)
        if mat is None:
            # a badly formed line
            raise SyntaxError
        (value, comment) = mat.groups()
        return (newvalue + value, comment, cur_index)

    def _handle_configspec(self, configspec):
        """Parse the configspec."""
        # FIXME: Should we check that the configspec was created with the 
        #   correct settings ? (i.e. ``list_values=False``)
        if not isinstance(configspec, ConfigObj):
            try:
                configspec = ConfigObj(
                    configspec,
                    raise_errors=True,
                    file_error=True,
                    list_values=False)
            except ConfigObjError, e:
                # FIXME: Should these errors have a reference
                # to the already parsed ConfigObj ?
                raise ConfigspecError('Parsing configspec failed: %s' % e)
            except IOError, e:
                raise IOError('Reading configspec failed: %s' % e)
        self._set_configspec_value(configspec, self)

    def _set_configspec_value(self, configspec, section):
        """Used to recursively set configspec values."""
        if '__many__' in configspec.sections:
            section.configspec['__many__'] = configspec['__many__']
            if len(configspec.sections) > 1:
                # FIXME: can we supply any useful information here ?
                raise RepeatSectionError
        if hasattr(configspec, 'initial_comment'):
            section._configspec_initial_comment = configspec.initial_comment
            section._configspec_final_comment = configspec.final_comment
            section._configspec_encoding = configspec.encoding
            section._configspec_BOM = configspec.BOM
            section._configspec_newlines = configspec.newlines
            section._configspec_indent_type = configspec.indent_type
        for entry in configspec.scalars:
            section._configspec_comments[entry] = configspec.comments[entry]
            section._configspec_inline_comments[entry] = (
                configspec.inline_comments[entry])
            section.configspec[entry] = configspec[entry]
            section._order.append(entry)
        for entry in configspec.sections:
            if entry == '__many__':
                continue
            section._cs_section_comments[entry] = configspec.comments[entry]
            section._cs_section_inline_comments[entry] = (
                configspec.inline_comments[entry])
            if not section.has_key(entry):
                section[entry] = {}
            self._set_configspec_value(configspec[entry], section[entry])

    def _handle_repeat(self, section, configspec):
        """Dynamically assign configspec for repeated section."""
        try:
            section_keys = configspec.sections
            scalar_keys = configspec.scalars
        except AttributeError:
            section_keys = [entry for entry in configspec 
                                if isinstance(configspec[entry], dict)]
            scalar_keys = [entry for entry in configspec 
                                if not isinstance(configspec[entry], dict)]
        if '__many__' in section_keys and len(section_keys) > 1:
            # FIXME: can we supply any useful information here ?
            raise RepeatSectionError
        scalars = {}
        sections = {}
        for entry in scalar_keys:
            val = configspec[entry]
            scalars[entry] = val
        for entry in section_keys:
            val = configspec[entry]
            if entry == '__many__':
                scalars[entry] = val
                continue
            sections[entry] = val
        #
        section.configspec = scalars
        for entry in sections:
            if not section.has_key(entry):
                section[entry] = {}
            self._handle_repeat(section[entry], sections[entry])

    def _write_line(self, indent_string, entry, this_entry, comment):
        """Write an individual line, for the write method"""
        # NOTE: the calls to self._quote here handles non-StringType values.
        if not self.unrepr:
            val = self._decode_element(self._quote(this_entry))
        else:
            val = repr(this_entry)
        return '%s%s%s%s%s' % (
            indent_string,
            self._decode_element(self._quote(entry, multiline=False)),
            self._a_to_u(' = '),
            val,
            self._decode_element(comment))

    def _write_marker(self, indent_string, depth, entry, comment):
        """Write a section marker line"""
        return '%s%s%s%s%s' % (
            indent_string,
            self._a_to_u('[' * depth),
            self._quote(self._decode_element(entry), multiline=False),
            self._a_to_u(']' * depth),
            self._decode_element(comment))

    def _handle_comment(self, comment):
        """Deal with a comment."""
        if not comment:
            return ''
        if self.indent_type == '\t':
            start = self._a_to_u('\t')
        else:
            start = self._a_to_u(' ' * NUM_INDENT_SPACES)
        if not comment.startswith('#'):
            start += _a_to_u('# ')
        return (start + comment)

    def _compute_indent_string(self, depth):
        """
        Compute the indent string, according to current indent_type and depth
        """
        if self.indent_type == '':
            # no indentation at all
            return ''
        if self.indent_type == '\t':
            return '\t' * depth
        if self.indent_type == ' ':
            return ' ' * NUM_INDENT_SPACES * depth
        raise SyntaxError

    # Public methods

    def write(self, outfile=None, section=None):
        """
        Write the current ConfigObj as a file
        
        tekNico: FIXME: use StringIO instead of real files
        
        >>> filename = a.filename
        >>> a.filename = 'test.ini'
        >>> a.write()
        >>> a.filename = filename
        >>> a == ConfigObj('test.ini', raise_errors=True)
        1
        """
        if self.indent_type is None:
            # this can be true if initialised from a dictionary
            self.indent_type = DEFAULT_INDENT_TYPE
        #
        out = []
        cs = self._a_to_u('#')
        csp = self._a_to_u('# ')
        if section is None:
            int_val = self.interpolation
            self.interpolation = False
            section = self
            for line in self.initial_comment:
                line = self._decode_element(line)
                stripped_line = line.strip()
                if stripped_line and not stripped_line.startswith(cs):
                    line = csp + line
                out.append(line)
        #
        indent_string = self._a_to_u(
            self._compute_indent_string(section.depth))
        for entry in (section.scalars + section.sections):
            if entry in section.defaults:
                # don't write out default values
                continue
            for comment_line in section.comments[entry]:
                comment_line = self._decode_element(comment_line.lstrip())
                if comment_line and not comment_line.startswith(cs):
                    comment_line = csp + comment_line
                out.append(indent_string + comment_line)
            this_entry = section[entry]
            comment = self._handle_comment(section.inline_comments[entry])
            #
            if isinstance(this_entry, dict):
                # a section
                out.append(self._write_marker(
                    indent_string,
                    this_entry.depth,
                    entry,
                    comment))
                out.extend(self.write(section=this_entry))
            else:
                out.append(self._write_line(
                    indent_string,
                    entry,
                    this_entry,
                    comment))
        #
        if section is self:
            for line in self.final_comment:
                line = self._decode_element(line)
                stripped_line = line.strip()
                if stripped_line and not stripped_line.startswith(cs):
                    line = csp + line
                out.append(line)
            self.interpolation = int_val
        #
        if section is not self:
            return out
        #
        if (self.filename is None) and (outfile is None):
            # output a list of lines
            # might need to encode
            # NOTE: This will *screw* UTF16, each line will start with the BOM
            if self.encoding:
                out = [l.encode(self.encoding) for l in out]
            if (self.BOM and ((self.encoding is None) or
                (BOM_LIST.get(self.encoding.lower()) == 'utf_8'))):
                # Add the UTF8 BOM
                if not out:
                    out.append('')
                out[0] = BOM_UTF8 + out[0]
            return out
        #
        # Turn the list to a string, joined with correct newlines
        output = (self._a_to_u(self.newlines or os.linesep)
            ).join(out)
        if self.encoding:
            output = output.encode(self.encoding)
        if (self.BOM and ((self.encoding is None) or
            (BOM_LIST.get(self.encoding.lower()) == 'utf_8'))):
            # Add the UTF8 BOM
            output = BOM_UTF8 + output
        if outfile is not None:
            outfile.write(output)
        else:
            h = open(self.filename, 'wb')
            h.write(output)
            h.close()

    def validate(self, validator, preserve_errors=False, copy=False,
        section=None):
        """
        Test the ConfigObj against a configspec.
        
        It uses the ``validator`` object from *validate.py*.
        
        To run ``validate`` on the current ConfigObj, call: ::
        
            test = config.validate(validator)
        
        (Normally having previously passed in the configspec when the ConfigObj
        was created - you can dynamically assign a dictionary of checks to the
        ``configspec`` attribute of a section though).
        
        It returns ``True`` if everything passes, or a dictionary of
        pass/fails (True/False). If every member of a subsection passes, it
        will just have the value ``True``. (It also returns ``False`` if all
        members fail).
        
        In addition, it converts the values from strings to their native
        types if their checks pass (and ``stringify`` is set).
        
        If ``preserve_errors`` is ``True`` (``False`` is default) then instead
        of a marking a fail with a ``False``, it will preserve the actual
        exception object. This can contain info about the reason for failure.
        For example the ``VdtValueTooSmallError`` indeicates that the value
        supplied was too small. If a value (or section) is missing it will
        still be marked as ``False``.
        
        You must have the validate module to use ``preserve_errors=True``.
        
        You can then use the ``flatten_errors`` function to turn your nested
        results dictionary into a flattened list of failures - useful for
        displaying meaningful error messages.
        """
        if section is None:
            if self.configspec is None:
                raise ValueError, 'No configspec supplied.'
            if preserve_errors:
                if VdtMissingValue is None:
                    raise ImportError('Missing validate module.')
            section = self
        #
        spec_section = section.configspec
        if copy and hasattr(section, '_configspec_initial_comment'):
            section.initial_comment = section._configspec_initial_comment
            section.final_comment = section._configspec_final_comment
            section.encoding = section._configspec_encoding
            section.BOM = section._configspec_BOM
            section.newlines = section._configspec_newlines
            section.indent_type = section._configspec_indent_type
        if '__many__' in section.configspec:
            many = spec_section['__many__']
            # dynamically assign the configspecs
            # for the sections below
            for entry in section.sections:
                self._handle_repeat(section[entry], many)
        #
        out = {}
        ret_true = True
        ret_false = True
        order = [k for k in section._order if k in spec_section]
        order += [k for k in spec_section if k not in order]
        for entry in order:
            if entry == '__many__':
                continue
            if (not entry in section.scalars) or (entry in section.defaults):
                # missing entries
                # or entries from defaults
                missing = True
                val = None
                if copy and not entry in section.scalars:
                    # copy comments
                    section.comments[entry] = (
                        section._configspec_comments.get(entry, []))
                    section.inline_comments[entry] = (
                        section._configspec_inline_comments.get(entry, ''))
                #
            else:
                missing = False
                val = section[entry]
            try:
                check = validator.check(spec_section[entry],
                                        val,
                                        missing=missing
                                        )
            except validator.baseErrorClass, e:
                if not preserve_errors or isinstance(e, VdtMissingValue):
                    out[entry] = False
                else:
                    # preserve the error
                    out[entry] = e
                    ret_false = False
                ret_true = False
            else:
                ret_false = False
                out[entry] = True
                if self.stringify or missing:
                    # if we are doing type conversion
                    # or the value is a supplied default
                    if not self.stringify:
                        if isinstance(check, (list, tuple)):
                            # preserve lists
                            check = [self._str(item) for item in check]
                        elif missing and check is None:
                            # convert the None from a default to a ''
                            check = ''
                        else:
                            check = self._str(check)
                    if (check != val) or missing:
                        section[entry] = check
                if not copy and missing and entry not in section.defaults:
                    section.defaults.append(entry)
        #
        # Missing sections will have been created as empty ones when the
        # configspec was read.
        for entry in section.sections:
            # FIXME: this means DEFAULT is not copied in copy mode
            if section is self and entry == 'DEFAULT':
                continue
            if copy:
                section.comments[entry] = section._cs_section_comments[entry]
                section.inline_comments[entry] = (
                    section._cs_section_inline_comments[entry])
            check = self.validate(validator, preserve_errors=preserve_errors,
                copy=copy, section=section[entry])
            out[entry] = check
            if check == False:
                ret_true = False
            elif check == True:
                ret_false = False
            else:
                ret_true = False
                ret_false = False
        #
        if ret_true:
            return True
        elif ret_false:
            return False
        else:
            return out

class SimpleVal(object):
    """
    A simple validator.
    Can be used to check that all members expected are present.
    
    To use it, provide a configspec with all your members in (the value given
    will be ignored). Pass an instance of ``SimpleVal`` to the ``validate``
    method of your ``ConfigObj``. ``validate`` will return ``True`` if all
    members are present, or a dictionary with True/False meaning
    present/missing. (Whole missing sections will be replaced with ``False``)
    """
    
    def __init__(self):
        self.baseErrorClass = ConfigObjError
    
    def check(self, check, member, missing=False):
        """A dummy check method, always returns the value unchanged."""
        if missing:
            raise self.baseErrorClass
        return member

# Check / processing functions for options
def flatten_errors(cfg, res, levels=None, results=None):
    """
    An example function that will turn a nested dictionary of results
    (as returned by ``ConfigObj.validate``) into a flat list.
    
    ``cfg`` is the ConfigObj instance being checked, ``res`` is the results
    dictionary returned by ``validate``.
    
    (This is a recursive function, so you shouldn't use the ``levels`` or
    ``results`` arguments - they are used by the function.
    
    Returns a list of keys that failed. Each member of the list is a tuple :
    ::
    
        ([list of sections...], key, result)
    
    If ``validate`` was called with ``preserve_errors=False`` (the default)
    then ``result`` will always be ``False``.

    *list of sections* is a flattened list of sections that the key was found
    in.
    
    If the section was missing then key will be ``None``.
    
    If the value (or section) was missing then ``result`` will be ``False``.
    
    If ``validate`` was called with ``preserve_errors=True`` and a value
    was present, but failed the check, then ``result`` will be the exception
    object returned. You can use this as a string that describes the failure.
    
    For example *The value "3" is of the wrong type*.
    
    >>> import validate
    >>> vtor = validate.Validator()
    >>> my_ini = '''
    ...     option1 = True
    ...     [section1]
    ...     option1 = True
    ...     [section2]
    ...     another_option = Probably
    ...     [section3]
    ...     another_option = True
    ...     [[section3b]]
    ...     value = 3
    ...     value2 = a
    ...     value3 = 11
    ...     '''
    >>> my_cfg = '''
    ...     option1 = boolean()
    ...     option2 = boolean()
    ...     option3 = boolean(default=Bad_value)
    ...     [section1]
    ...     option1 = boolean()
    ...     option2 = boolean()
    ...     option3 = boolean(default=Bad_value)
    ...     [section2]
    ...     another_option = boolean()
    ...     [section3]
    ...     another_option = boolean()
    ...     [[section3b]]
    ...     value = integer
    ...     value2 = integer
    ...     value3 = integer(0, 10)
    ...         [[[section3b-sub]]]
    ...         value = string
    ...     [section4]
    ...     another_option = boolean()
    ...     '''
    >>> cs = my_cfg.split('\\n')
    >>> ini = my_ini.split('\\n')
    >>> cfg = ConfigObj(ini, configspec=cs)
    >>> res = cfg.validate(vtor, preserve_errors=True)
    >>> errors = []
    >>> for entry in flatten_errors(cfg, res):
    ...     section_list, key, error = entry
    ...     section_list.insert(0, '[root]')
    ...     if key is not None:
    ...        section_list.append(key)
    ...     else:
    ...         section_list.append('[missing]')
    ...     section_string = ', '.join(section_list)
    ...     errors.append((section_string, ' = ', error))
    >>> errors.sort()
    >>> for entry in errors:
    ...     print entry[0], entry[1], (entry[2] or 0)
    [root], option2  =  0
    [root], option3  =  the value "Bad_value" is of the wrong type.
    [root], section1, option2  =  0
    [root], section1, option3  =  the value "Bad_value" is of the wrong type.
    [root], section2, another_option  =  the value "Probably" is of the wrong type.
    [root], section3, section3b, section3b-sub, [missing]  =  0
    [root], section3, section3b, value2  =  the value "a" is of the wrong type.
    [root], section3, section3b, value3  =  the value "11" is too big.
    [root], section4, [missing]  =  0
    """
    if levels is None:
        # first time called
        levels = []
        results = []
    if res is True:
        return results
    if res is False:
        results.append((levels[:], None, False))
        if levels:
            levels.pop()
        return results
    for (key, val) in res.items():
        if val == True:
            continue
        if isinstance(cfg.get(key), dict):
            # Go down one level
            levels.append(key)
            flatten_errors(cfg[key], val, levels, results)
            continue
        results.append((levels[:], key, val))
    #
    # Go up one level
    if levels:
        levels.pop()
    #
    return results

"""*A programming language is a medium of expression.* - Paul Graham"""
