Checking in ConfigParser.py -- I don't see a reason why this can't be

liberated.  This was originally written by Ken and later revamped by
Barry.

Lib/ConfigParser.py

+"""Configuration file parser.
+
+A setup file consists of sections, lead by a "[section]" header,
+and followed by "name: value" entries, with continuations and such in
+the style of rfc822.
+
+The option values can contain format strings which refer to other
+values in the same section, or values in a special [DEFAULT] section.
+For example:
+
+    something: %(dir)s/whatever
+
+would resolve the "%(dir)s" to the value of dir.  All reference
+expansions are done late, on demand.
+
+Intrinsic defaults can be specified by passing them into the
+ConfigParser constructor as a dictionary.
+
+class:
+
+ConfigParser -- responsible for for parsing a list of
+                configuration files, and managing the parsed database.
+
+    methods:
+
+    __init__(defaults=None) -- create the parser and specify a
+                               dictionary of intrinsic defaults.  The
+                               keys must be strings, the values must
+                               be appropriate for %()s string
+                               interpolation.  Note that `name' is
+                               always an intrinsic default; it's value
+                               is the section's name.
+
+    sections() -- return all the configuration section names, sans DEFAULT
+
+    options(section) -- return list of configuration options for the named
+			section
+
+    read(*filenames) -- read and parse the list of named configuration files
+
+    get(section, option, raw=0) -- return a string value for the named
+				   option.  All % interpolations are
+				   expanded in the return values, based on
+				   the defaults passed into the constructor
+				   and the DEFAULT section.
+
+    getint(section, options) -- like get(), but convert value to an integer
+
+    getfloat(section, options) -- like get(), but convert value to a float
+
+    getboolean(section, options) -- like get(), but convert value to
+				    a boolean (currently defined as 0
+				    or 1, only)
+"""
+
+import sys
+import string
+import regex
+from types import ListType
+
+
+SECTHEAD_RE = "^\[\([-A-Za-z0-9]*\)\][" + string.whitespace + "]*$"
+secthead_cre = regex.compile(SECTHEAD_RE)
+OPTION_RE = "^\([-A-Za-z0-9.]+\)\(:\|[" + string.whitespace + "]*=\)\(.*\)$"
+option_cre = regex.compile(OPTION_RE)
+
+DEFAULTSECT = "DEFAULT"
+
+
+
+# exception classes
+class Error:
+    def __init__(self, msg=''):
+	self.__msg = msg
+    def __repr__(self):
+	return self.__msg
+
+class NoSectionError(Error):
+    def __init__(self, section):
+	Error.__init__(self, 'No section: %s' % section)
+	self.section = section
+
+class DuplicateSectionError(Error):
+    def __init__(self, section):
+	Error.__init__(self, "Section %s already exists" % section)
+	self.section = section
+
+class NoOptionError(Error):
+    def __init__(self, option, section):
+	Error.__init__(self, "No option `%s' in section: %s" %
+		       (option, section))
+	self.option = option
+	self.section = section
+
+class InterpolationError(Error):
+    def __init__(self, reference, option, section):
+	Error.__init__(self,
+		       "Bad value substitution: sect `%s', opt `%s', ref `%s'"
+		       % (section, option, reference))
+	self.reference = reference
+	self.option = option
+	self.section = section
+
+
+
+class ConfigParser:
+    def __init__(self, defaults=None):
+	self.__sections = {}
+	if defaults is None:
+	    self.__defaults = {}
+	else:
+	    self.__defaults = defaults
+
+    def defaults(self):
+	return self.__defaults
+
+    def sections(self):
+	"""Return a list of section names, excluding [DEFAULT]"""
+	# self.__sections will never have [DEFAULT] in it
+	return self.__sections.keys()
+
+    def add_section(self, section):
+	"""Create a new section in the configuration.
+
+	Raise DuplicateSectionError if a section by the specified name
+	already exists.
+	"""
+	if self.__sections.has_key(section):
+	    raise DuplicateSectionError(section)
+	self.__sections[section] = {}
+
+    def has_section(self, section):
+	"""Indicate whether the named section is present in the configuration.
+
+	The DEFAULT section is not acknowledged.
+	"""
+	return self.__sections.has_key(section)
+
+    def options(self, section):
+	try:
+	    opts = self.__sections[section].copy()
+	except KeyError:
+	    raise NoSectionError(section)
+	opts.update(self.__defaults)
+	return opts.keys()
+
+    def read(self, filenames):
+	"""Read and parse a list of filenames."""
+	if type(filenames) is type(''):
+	    filenames = [filenames]
+	for file in filenames:
+	    try:
+		fp = open(file, 'r')
+		self.__read(fp)
+	    except IOError:
+		pass
+
+    def get(self, section, option, raw=0):
+	"""Get an option value for a given section.
+
+	All % interpolations are expanded in the return values, based
+	on the defaults passed into the constructor.
+
+	The section DEFAULT is special.
+	"""
+	try:
+	    d = self.__sections[section].copy()
+	except KeyError:
+	    if section == DEFAULTSECT:
+		d = {}
+	    else:
+		raise NoSectionError(section)
+	d.update(self.__defaults)
+	option = string.lower(option)
+	try:
+	    rawval = d[option]
+	except KeyError:
+	    raise NoOptionError(option, section)
+	# do the string interpolation
+	if raw:
+	    return rawval
+	try:
+	    return rawval % d
+	except KeyError, key:
+	    raise InterpolationError(key, option, section)
+
+    def __get(self, section, conv, option):
+	return conv(self.get(section, option))
+
+    def getint(self, section, option):
+	return self.__get(section, string.atoi, option)
+
+    def getfloat(self, section, option):
+	return self.__get(section, string.atof, option)
+
+    def getboolean(self, section, option):
+	v = self.get(section, option)
+	val = string.atoi(v)
+	if val not in (0, 1):
+	    raise ValueError, 'Not a boolean: %s' % v
+	return val
+
+    def __read(self, fp):
+	"""Parse a sectioned setup file.
+
+	The sections in setup file contains a title line at the top,
+	indicated by a name in square brackets (`[]'), plus key/value
+	options lines, indicated by `name: value' format lines.
+	Continuation are represented by an embedded newline then
+	leading whitespace.  Blank lines, lines beginning with a '#',
+	and just about everything else is ignored.
+	"""
+	cursect = None			# None, or a dictionary
+	optname = None
+	lineno = 0
+	while 1:
+	    line = fp.readline()
+	    if not line:
+		break
+	    lineno = lineno + 1
+	    # comment or blank line?
+	    if string.strip(line) == '' or line[0] in '#;':
+		continue
+	    if string.lower(string.split(line)[0]) == 'rem' \
+	       and line[0] == "r":	# no leading whitespace
+		continue
+	    # continuation line?
+	    if line[0] in ' \t' and cursect <> None and optname:
+		value = string.strip(line)
+		if value:
+		    cursect = cursect[optname] + '\n ' + value
+	    # a section header?
+	    elif secthead_cre.match(line) >= 0:
+		sectname = secthead_cre.group(1)
+		if self.__sections.has_key(sectname):
+		    cursect = self.__sections[sectname]
+		elif sectname == DEFAULTSECT:
+		    cursect = self.__defaults
+		else:
+		    cursect = {'name': sectname}
+		    self.__sections[sectname] = cursect
+		# So sections can't start with a continuation line.
+		optname = None
+	    # an option line?
+	    elif option_cre.match(line) >= 0:
+		optname, optval = option_cre.group(1, 3)
+		optname = string.lower(optname)
+		optval = string.strip(optval)
+		# allow empty values
+		if optval == '""':
+		    optval = ''
+		cursect[optname] = optval
+	    # an error
+	    else:
+		print 'Error in %s at %d: %s', (fp.name, lineno, `line`)