--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/env/lib/python3.7/site-packages/docutils/frontend.py	Sat May 02 07:14:21 2020 -0400
@@ -0,0 +1,863 @@
+# $Id: frontend.py 8439 2019-12-13 17:02:41Z milde $
+# Author: David Goodger <goodger@python.org>
+# Copyright: This module has been placed in the public domain.
+
+"""
+Command-line and common processing for Docutils front-end tools.
+
+Exports the following classes:
+
+* `OptionParser`: Standard Docutils command-line processing.
+* `Option`: Customized version of `optparse.Option`; validation support.
+* `Values`: Runtime settings; objects are simple structs
+  (``object.attribute``).  Supports cumulative list settings (attributes).
+* `ConfigParser`: Standard Docutils config file processing.
+
+Also exports the following functions:
+
+* Option callbacks: `store_multiple`, `read_config_file`.
+* Setting validators: `validate_encoding`,
+  `validate_encoding_error_handler`,
+  `validate_encoding_and_error_handler`,
+  `validate_boolean`, `validate_ternary`, `validate_threshold`,
+  `validate_colon_separated_string_list`,
+  `validate_comma_separated_string_list`,
+  `validate_dependency_file`.
+* `make_paths_absolute`.
+* SettingSpec manipulation: `filter_settings_spec`.
+"""
+
+__docformat__ = 'reStructuredText'
+
+import os
+import os.path
+import sys
+import warnings
+import codecs
+import optparse
+from optparse import SUPPRESS_HELP
+if sys.version_info >= (3, 0):
+    from configparser import RawConfigParser
+    from os import getcwd
+else:
+    from ConfigParser import RawConfigParser
+    from os import getcwdu as getcwd
+
+import docutils
+import docutils.utils
+import docutils.nodes
+from docutils.utils.error_reporting import (locale_encoding, SafeString,
+                                            ErrorOutput, ErrorString)
+
+if sys.version_info >= (3, 0):
+    unicode = str  # noqa
+
+
+def store_multiple(option, opt, value, parser, *args, **kwargs):
+    """
+    Store multiple values in `parser.values`.  (Option callback.)
+
+    Store `None` for each attribute named in `args`, and store the value for
+    each key (attribute name) in `kwargs`.
+    """
+    for attribute in args:
+        setattr(parser.values, attribute, None)
+    for key, value in kwargs.items():
+        setattr(parser.values, key, value)
+
+def read_config_file(option, opt, value, parser):
+    """
+    Read a configuration file during option processing.  (Option callback.)
+    """
+    try:
+        new_settings = parser.get_config_file_settings(value)
+    except ValueError as error:
+        parser.error(error)
+    parser.values.update(new_settings, parser)
+
+def validate_encoding(setting, value, option_parser,
+                      config_parser=None, config_section=None):
+    try:
+        codecs.lookup(value)
+    except LookupError:
+        raise LookupError('setting "%s": unknown encoding: "%s"'
+                          % (setting, value))
+    return value
+
+def validate_encoding_error_handler(setting, value, option_parser,
+                                    config_parser=None, config_section=None):
+    try:
+        codecs.lookup_error(value)
+    except LookupError:
+        raise LookupError(
+            'unknown encoding error handler: "%s" (choices: '
+            '"strict", "ignore", "replace", "backslashreplace", '
+            '"xmlcharrefreplace", and possibly others; see documentation for '
+            'the Python ``codecs`` module)' % value)
+    return value
+
+def validate_encoding_and_error_handler(
+    setting, value, option_parser, config_parser=None, config_section=None):
+    """
+    Side-effect: if an error handler is included in the value, it is inserted
+    into the appropriate place as if it was a separate setting/option.
+    """
+    if ':' in value:
+        encoding, handler = value.split(':')
+        validate_encoding_error_handler(
+            setting + '_error_handler', handler, option_parser,
+            config_parser, config_section)
+        if config_parser:
+            config_parser.set(config_section, setting + '_error_handler',
+                              handler)
+        else:
+            setattr(option_parser.values, setting + '_error_handler', handler)
+    else:
+        encoding = value
+    validate_encoding(setting, encoding, option_parser,
+                      config_parser, config_section)
+    return encoding
+
+def validate_boolean(setting, value, option_parser,
+                     config_parser=None, config_section=None):
+    """Check/normalize boolean settings:
+         True:  '1', 'on', 'yes', 'true'
+         False: '0', 'off', 'no','false', ''
+    """
+    if isinstance(value, bool):
+        return value
+    try:
+        return option_parser.booleans[value.strip().lower()]
+    except KeyError:
+        raise LookupError('unknown boolean value: "%s"' % value)
+
+def validate_ternary(setting, value, option_parser,
+                     config_parser=None, config_section=None):
+    """Check/normalize three-value settings:
+         True:  '1', 'on', 'yes', 'true'
+         False: '0', 'off', 'no','false', ''
+         any other value: returned as-is.
+    """
+    if isinstance(value, bool) or value is None:
+        return value
+    try:
+        return option_parser.booleans[value.strip().lower()]
+    except KeyError:
+        return value
+
+def validate_nonnegative_int(setting, value, option_parser,
+                             config_parser=None, config_section=None):
+    value = int(value)
+    if value < 0:
+        raise ValueError('negative value; must be positive or zero')
+    return value
+
+def validate_threshold(setting, value, option_parser,
+                       config_parser=None, config_section=None):
+    try:
+        return int(value)
+    except ValueError:
+        try:
+            return option_parser.thresholds[value.lower()]
+        except (KeyError, AttributeError):
+            raise LookupError('unknown threshold: %r.' % value)
+
+def validate_colon_separated_string_list(
+    setting, value, option_parser, config_parser=None, config_section=None):
+    if not isinstance(value, list):
+        value = value.split(':')
+    else:
+        last = value.pop()
+        value.extend(last.split(':'))
+    return value
+
+def validate_comma_separated_list(setting, value, option_parser,
+                                    config_parser=None, config_section=None):
+    """Check/normalize list arguments (split at "," and strip whitespace).
+    """
+    # `value` is already a ``list`` when  given as command line option
+    # and "action" is "append" and ``unicode`` or ``str`` else.
+    if not isinstance(value, list):
+        value = [value]
+    # this function is called for every option added to `value`
+    # -> split the last item and append the result:
+    last = value.pop()
+    items = [i.strip(u' \t\n') for i in last.split(u',') if i.strip(u' \t\n')]
+    value.extend(items)
+    return value
+
+def validate_url_trailing_slash(
+    setting, value, option_parser, config_parser=None, config_section=None):
+    if not value:
+        return './'
+    elif value.endswith('/'):
+        return value
+    else:
+        return value + '/'
+
+def validate_dependency_file(setting, value, option_parser,
+                             config_parser=None, config_section=None):
+    try:
+        return docutils.utils.DependencyList(value)
+    except IOError:
+        return docutils.utils.DependencyList(None)
+
+def validate_strip_class(setting, value, option_parser,
+                         config_parser=None, config_section=None):
+    # value is a comma separated string list:
+    value = validate_comma_separated_list(setting, value, option_parser,
+                                          config_parser, config_section)
+    # validate list elements:
+    for cls in value:
+        normalized = docutils.nodes.make_id(cls)
+        if cls != normalized:
+            raise ValueError('Invalid class value %r (perhaps %r?)'
+                             % (cls, normalized))
+    return value
+
+def validate_smartquotes_locales(setting, value, option_parser,
+                         config_parser=None, config_section=None):
+    """Check/normalize a comma separated list of smart quote definitions.
+
+    Return a list of (language-tag, quotes) string tuples."""
+
+    # value is a comma separated string list:
+    value = validate_comma_separated_list(setting, value, option_parser,
+                                          config_parser, config_section)
+    # validate list elements
+    lc_quotes = []
+    for item in value:
+        try:
+            lang, quotes = item.split(':', 1)
+        except AttributeError:
+            # this function is called for every option added to `value`
+            # -> ignore if already a tuple:
+            lc_quotes.append(item)
+            continue
+        except ValueError:
+            raise ValueError(u'Invalid value "%s".'
+                             ' Format is "<language>:<quotes>".'
+                             % item.encode('ascii', 'backslashreplace'))
+        # parse colon separated string list:
+        quotes = quotes.strip()
+        multichar_quotes = quotes.split(':')
+        if len(multichar_quotes) == 4:
+            quotes = multichar_quotes
+        elif len(quotes) != 4:
+            raise ValueError('Invalid value "%s". Please specify 4 quotes\n'
+                '    (primary open/close; secondary open/close).'
+                             % item.encode('ascii', 'backslashreplace'))
+        lc_quotes.append((lang, quotes))
+    return lc_quotes
+
+def make_paths_absolute(pathdict, keys, base_path=None):
+    """
+    Interpret filesystem path settings relative to the `base_path` given.
+
+    Paths are values in `pathdict` whose keys are in `keys`.  Get `keys` from
+    `OptionParser.relative_path_settings`.
+    """
+    if base_path is None:
+        base_path = getcwd() # type(base_path) == unicode
+        # to allow combining non-ASCII cwd with unicode values in `pathdict`
+    for key in keys:
+        if key in pathdict:
+            value = pathdict[key]
+            if isinstance(value, list):
+                value = [make_one_path_absolute(base_path, path)
+                         for path in value]
+            elif value:
+                value = make_one_path_absolute(base_path, value)
+            pathdict[key] = value
+
+def make_one_path_absolute(base_path, path):
+    return os.path.abspath(os.path.join(base_path, path))
+
+def filter_settings_spec(settings_spec, *exclude, **replace):
+    """Return a copy of `settings_spec` excluding/replacing some settings.
+
+    `settings_spec` is a tuple of configuration settings with a structure
+    described for docutils.SettingsSpec.settings_spec.
+
+    Optional positional arguments are names of to-be-excluded settings.
+    Keyword arguments are option specification replacements.
+    (See the html4strict writer for an example.)
+    """
+    settings = list(settings_spec)
+    # every third item is a sequence of option tuples
+    for i in range(2, len(settings), 3):
+        newopts = []
+        for opt_spec in settings[i]:
+            # opt_spec is ("<help>", [<option strings>], {<keyword args>})
+            opt_name = [opt_string[2:].replace('-', '_')
+                        for opt_string in opt_spec[1]
+                            if opt_string.startswith('--')
+                       ][0]
+            if opt_name in exclude:
+                continue
+            if opt_name in replace.keys():
+                newopts.append(replace[opt_name])
+            else:
+                newopts.append(opt_spec)
+        settings[i] = tuple(newopts)
+    return tuple(settings)
+
+
+class Values(optparse.Values):
+
+    """
+    Updates list attributes by extension rather than by replacement.
+    Works in conjunction with the `OptionParser.lists` instance attribute.
+    """
+
+    def __init__(self, *args, **kwargs):
+        optparse.Values.__init__(self, *args, **kwargs)
+        if (not hasattr(self, 'record_dependencies')
+            or self.record_dependencies is None):
+            # Set up dependency list, in case it is needed.
+            self.record_dependencies = docutils.utils.DependencyList()
+
+    def update(self, other_dict, option_parser):
+        if isinstance(other_dict, Values):
+            other_dict = other_dict.__dict__
+        other_dict = other_dict.copy()
+        for setting in option_parser.lists.keys():
+            if (hasattr(self, setting) and setting in other_dict):
+                value = getattr(self, setting)
+                if value:
+                    value += other_dict[setting]
+                    del other_dict[setting]
+        self._update_loose(other_dict)
+
+    def copy(self):
+        """Return a shallow copy of `self`."""
+        return self.__class__(defaults=self.__dict__)
+
+
+class Option(optparse.Option):
+
+    ATTRS = optparse.Option.ATTRS + ['validator', 'overrides']
+
+    def process(self, opt, value, values, parser):
+        """
+        Call the validator function on applicable settings and
+        evaluate the 'overrides' option.
+        Extends `optparse.Option.process`.
+        """
+        result = optparse.Option.process(self, opt, value, values, parser)
+        setting = self.dest
+        if setting:
+            if self.validator:
+                value = getattr(values, setting)
+                try:
+                    new_value = self.validator(setting, value, parser)
+                except Exception as error:
+                    raise optparse.OptionValueError(
+                        'Error in option "%s":\n    %s'
+                        % (opt, ErrorString(error)))
+                setattr(values, setting, new_value)
+            if self.overrides:
+                setattr(values, self.overrides, None)
+        return result
+
+
+class OptionParser(optparse.OptionParser, docutils.SettingsSpec):
+
+    """
+    Parser for command-line and library use.  The `settings_spec`
+    specification here and in other Docutils components are merged to build
+    the set of command-line options and runtime settings for this process.
+
+    Common settings (defined below) and component-specific settings must not
+    conflict.  Short options are reserved for common settings, and components
+    are restrict to using long options.
+    """
+
+    standard_config_files = [
+        '/etc/docutils.conf',           # system-wide
+        './docutils.conf',              # project-specific
+        '~/.docutils']                  # user-specific
+    """Docutils configuration files, using ConfigParser syntax.  Filenames
+    will be tilde-expanded later.  Later files override earlier ones."""
+
+    threshold_choices = 'info 1 warning 2 error 3 severe 4 none 5'.split()
+    """Possible inputs for for --report and --halt threshold values."""
+
+    thresholds = {'info': 1, 'warning': 2, 'error': 3, 'severe': 4, 'none': 5}
+    """Lookup table for --report and --halt threshold values."""
+
+    booleans={'1': True, 'on': True, 'yes': True, 'true': True,
+              '0': False, 'off': False, 'no': False, 'false': False, '': False}
+    """Lookup table for boolean configuration file settings."""
+
+    default_error_encoding = getattr(sys.stderr, 'encoding',
+                                     None) or locale_encoding or 'ascii'
+
+    default_error_encoding_error_handler = 'backslashreplace'
+
+    settings_spec = (
+        'General Docutils Options',
+        None,
+        (('Specify the document title as metadata.',
+          ['--title'], {}),
+         ('Include a "Generated by Docutils" credit and link.',
+          ['--generator', '-g'], {'action': 'store_true',
+                                  'validator': validate_boolean}),
+         ('Do not include a generator credit.',
+          ['--no-generator'], {'action': 'store_false', 'dest': 'generator'}),
+         ('Include the date at the end of the document (UTC).',
+          ['--date', '-d'], {'action': 'store_const', 'const': '%Y-%m-%d',
+                             'dest': 'datestamp'}),
+         ('Include the time & date (UTC).',
+          ['--time', '-t'], {'action': 'store_const',
+                             'const': '%Y-%m-%d %H:%M UTC',
+                             'dest': 'datestamp'}),
+         ('Do not include a datestamp of any kind.',
+          ['--no-datestamp'], {'action': 'store_const', 'const': None,
+                               'dest': 'datestamp'}),
+         ('Include a "View document source" link.',
+          ['--source-link', '-s'], {'action': 'store_true',
+                                    'validator': validate_boolean}),
+         ('Use <URL> for a source link; implies --source-link.',
+          ['--source-url'], {'metavar': '<URL>'}),
+         ('Do not include a "View document source" link.',
+          ['--no-source-link'],
+          {'action': 'callback', 'callback': store_multiple,
+           'callback_args': ('source_link', 'source_url')}),
+         ('Link from section headers to TOC entries.  (default)',
+          ['--toc-entry-backlinks'],
+          {'dest': 'toc_backlinks', 'action': 'store_const', 'const': 'entry',
+           'default': 'entry'}),
+         ('Link from section headers to the top of the TOC.',
+          ['--toc-top-backlinks'],
+          {'dest': 'toc_backlinks', 'action': 'store_const', 'const': 'top'}),
+         ('Disable backlinks to the table of contents.',
+          ['--no-toc-backlinks'],
+          {'dest': 'toc_backlinks', 'action': 'store_false'}),
+         ('Link from footnotes/citations to references. (default)',
+          ['--footnote-backlinks'],
+          {'action': 'store_true', 'default': 1,
+           'validator': validate_boolean}),
+         ('Disable backlinks from footnotes and citations.',
+          ['--no-footnote-backlinks'],
+          {'dest': 'footnote_backlinks', 'action': 'store_false'}),
+         ('Enable section numbering by Docutils.  (default)',
+          ['--section-numbering'],
+          {'action': 'store_true', 'dest': 'sectnum_xform',
+           'default': 1, 'validator': validate_boolean}),
+         ('Disable section numbering by Docutils.',
+          ['--no-section-numbering'],
+          {'action': 'store_false', 'dest': 'sectnum_xform'}),
+         ('Remove comment elements from the document tree.',
+          ['--strip-comments'],
+          {'action': 'store_true', 'validator': validate_boolean}),
+         ('Leave comment elements in the document tree. (default)',
+          ['--leave-comments'],
+          {'action': 'store_false', 'dest': 'strip_comments'}),
+         ('Remove all elements with classes="<class>" from the document tree. '
+          'Warning: potentially dangerous; use with caution. '
+          '(Multiple-use option.)',
+          ['--strip-elements-with-class'],
+          {'action': 'append', 'dest': 'strip_elements_with_classes',
+           'metavar': '<class>', 'validator': validate_strip_class}),
+         ('Remove all classes="<class>" attributes from elements in the '
+          'document tree. Warning: potentially dangerous; use with caution. '
+          '(Multiple-use option.)',
+          ['--strip-class'],
+          {'action': 'append', 'dest': 'strip_classes',
+           'metavar': '<class>', 'validator': validate_strip_class}),
+         ('Report system messages at or higher than <level>: "info" or "1", '
+          '"warning"/"2" (default), "error"/"3", "severe"/"4", "none"/"5"',
+          ['--report', '-r'], {'choices': threshold_choices, 'default': 2,
+                               'dest': 'report_level', 'metavar': '<level>',
+                               'validator': validate_threshold}),
+         ('Report all system messages.  (Same as "--report=1".)',
+          ['--verbose', '-v'], {'action': 'store_const', 'const': 1,
+                                'dest': 'report_level'}),
+         ('Report no system messages.  (Same as "--report=5".)',
+          ['--quiet', '-q'], {'action': 'store_const', 'const': 5,
+                              'dest': 'report_level'}),
+         ('Halt execution at system messages at or above <level>.  '
+          'Levels as in --report.  Default: 4 (severe).',
+          ['--halt'], {'choices': threshold_choices, 'dest': 'halt_level',
+                       'default': 4, 'metavar': '<level>',
+                       'validator': validate_threshold}),
+         ('Halt at the slightest problem.  Same as "--halt=info".',
+          ['--strict'], {'action': 'store_const', 'const': 1,
+                         'dest': 'halt_level'}),
+         ('Enable a non-zero exit status for non-halting system messages at '
+          'or above <level>.  Default: 5 (disabled).',
+          ['--exit-status'], {'choices': threshold_choices,
+                              'dest': 'exit_status_level',
+                              'default': 5, 'metavar': '<level>',
+                              'validator': validate_threshold}),
+         ('Enable debug-level system messages and diagnostics.',
+          ['--debug'], {'action': 'store_true', 'validator': validate_boolean}),
+         ('Disable debug output.  (default)',
+          ['--no-debug'], {'action': 'store_false', 'dest': 'debug'}),
+         ('Send the output of system messages to <file>.',
+          ['--warnings'], {'dest': 'warning_stream', 'metavar': '<file>'}),
+         ('Enable Python tracebacks when Docutils is halted.',
+          ['--traceback'], {'action': 'store_true', 'default': None,
+                            'validator': validate_boolean}),
+         ('Disable Python tracebacks.  (default)',
+          ['--no-traceback'], {'dest': 'traceback', 'action': 'store_false'}),
+         ('Specify the encoding and optionally the '
+          'error handler of input text.  Default: <locale-dependent>:strict.',
+          ['--input-encoding', '-i'],
+          {'metavar': '<name[:handler]>',
+           'validator': validate_encoding_and_error_handler}),
+         ('Specify the error handler for undecodable characters.  '
+          'Choices: "strict" (default), "ignore", and "replace".',
+          ['--input-encoding-error-handler'],
+          {'default': 'strict', 'validator': validate_encoding_error_handler}),
+         ('Specify the text encoding and optionally the error handler for '
+          'output.  Default: UTF-8:strict.',
+          ['--output-encoding', '-o'],
+          {'metavar': '<name[:handler]>', 'default': 'utf-8',
+           'validator': validate_encoding_and_error_handler}),
+         ('Specify error handler for unencodable output characters; '
+          '"strict" (default), "ignore", "replace", '
+          '"xmlcharrefreplace", "backslashreplace".',
+          ['--output-encoding-error-handler'],
+          {'default': 'strict', 'validator': validate_encoding_error_handler}),
+         ('Specify text encoding and error handler for error output.  '
+          'Default: %s:%s.'
+          % (default_error_encoding, default_error_encoding_error_handler),
+          ['--error-encoding', '-e'],
+          {'metavar': '<name[:handler]>', 'default': default_error_encoding,
+           'validator': validate_encoding_and_error_handler}),
+         ('Specify the error handler for unencodable characters in '
+          'error output.  Default: %s.'
+          % default_error_encoding_error_handler,
+          ['--error-encoding-error-handler'],
+          {'default': default_error_encoding_error_handler,
+           'validator': validate_encoding_error_handler}),
+         ('Specify the language (as BCP 47 language tag).  Default: en.',
+          ['--language', '-l'], {'dest': 'language_code', 'default': 'en',
+                                 'metavar': '<name>'}),
+         ('Write output file dependencies to <file>.',
+          ['--record-dependencies'],
+          {'metavar': '<file>', 'validator': validate_dependency_file,
+           'default': None}),           # default set in Values class
+         ('Read configuration settings from <file>, if it exists.',
+          ['--config'], {'metavar': '<file>', 'type': 'string',
+                         'action': 'callback', 'callback': read_config_file}),
+         ("Show this program's version number and exit.",
+          ['--version', '-V'], {'action': 'version'}),
+         ('Show this help message and exit.',
+          ['--help', '-h'], {'action': 'help'}),
+         # Typically not useful for non-programmatical use:
+         (SUPPRESS_HELP, ['--id-prefix'], {'default': ''}),
+         (SUPPRESS_HELP, ['--auto-id-prefix'], {'default': 'id'}),
+         # Hidden options, for development use only:
+         (SUPPRESS_HELP, ['--dump-settings'], {'action': 'store_true'}),
+         (SUPPRESS_HELP, ['--dump-internals'], {'action': 'store_true'}),
+         (SUPPRESS_HELP, ['--dump-transforms'], {'action': 'store_true'}),
+         (SUPPRESS_HELP, ['--dump-pseudo-xml'], {'action': 'store_true'}),
+         (SUPPRESS_HELP, ['--expose-internal-attribute'],
+          {'action': 'append', 'dest': 'expose_internals',
+           'validator': validate_colon_separated_string_list}),
+         (SUPPRESS_HELP, ['--strict-visitor'], {'action': 'store_true'}),
+         ))
+    """Runtime settings and command-line options common to all Docutils front
+    ends.  Setting specs specific to individual Docutils components are also
+    used (see `populate_from_components()`)."""
+
+    settings_defaults = {'_disable_config': None,
+                         '_source': None,
+                         '_destination': None,
+                         '_config_files': None}
+    """Defaults for settings that don't have command-line option equivalents."""
+
+    relative_path_settings = ('warning_stream',)
+
+    config_section = 'general'
+
+    version_template = ('%%prog (Docutils %s%s, Python %s, on %s)'
+                        % (docutils.__version__,
+                           docutils.__version_details__ and
+                           ' [%s]'%docutils.__version_details__ or '',
+                           sys.version.split()[0], sys.platform))
+    """Default version message."""
+
+    def __init__(self, components=(), defaults=None, read_config_files=None,
+                 *args, **kwargs):
+        """
+        `components` is a list of Docutils components each containing a
+        ``.settings_spec`` attribute.  `defaults` is a mapping of setting
+        default overrides.
+        """
+
+        self.lists = {}
+        """Set of list-type settings."""
+
+        self.config_files = []
+        """List of paths of applied configuration files."""
+
+        optparse.OptionParser.__init__(
+            self, option_class=Option, add_help_option=None,
+            formatter=optparse.TitledHelpFormatter(width=78),
+            *args, **kwargs)
+        if not self.version:
+            self.version = self.version_template
+        # Make an instance copy (it will be modified):
+        self.relative_path_settings = list(self.relative_path_settings)
+        self.components = (self,) + tuple(components)
+        self.populate_from_components(self.components)
+        self.set_defaults_from_dict(defaults or {})
+        if read_config_files and not self.defaults['_disable_config']:
+            try:
+                config_settings = self.get_standard_config_settings()
+            except ValueError as error:
+                self.error(SafeString(error))
+            self.set_defaults_from_dict(config_settings.__dict__)
+
+    def populate_from_components(self, components):
+        """
+        For each component, first populate from the `SettingsSpec.settings_spec`
+        structure, then from the `SettingsSpec.settings_defaults` dictionary.
+        After all components have been processed, check for and populate from
+        each component's `SettingsSpec.settings_default_overrides` dictionary.
+        """
+        for component in components:
+            if component is None:
+                continue
+            settings_spec = component.settings_spec
+            self.relative_path_settings.extend(
+                component.relative_path_settings)
+            for i in range(0, len(settings_spec), 3):
+                title, description, option_spec = settings_spec[i:i+3]
+                if title:
+                    group = optparse.OptionGroup(self, title, description)
+                    self.add_option_group(group)
+                else:
+                    group = self        # single options
+                for (help_text, option_strings, kwargs) in option_spec:
+                    option = group.add_option(help=help_text, *option_strings,
+                                              **kwargs)
+                    if kwargs.get('action') == 'append':
+                        self.lists[option.dest] = 1
+                if component.settings_defaults:
+                    self.defaults.update(component.settings_defaults)
+        for component in components:
+            if component and component.settings_default_overrides:
+                self.defaults.update(component.settings_default_overrides)
+
+    def get_standard_config_files(self):
+        """Return list of config files, from environment or standard."""
+        try:
+            config_files = os.environ['DOCUTILSCONFIG'].split(os.pathsep)
+        except KeyError:
+            config_files = self.standard_config_files
+
+        # If 'HOME' is not set, expandvars() requires the 'pwd' module which is
+        # not available under certain environments, for example, within
+        # mod_python.  The publisher ends up in here, and we need to publish
+        # from within mod_python.  Therefore we need to avoid expanding when we
+        # are in those environments.
+        expand = os.path.expanduser
+        if 'HOME' not in os.environ:
+            try:
+                import pwd
+            except ImportError:
+                expand = lambda x: x
+        return [expand(f) for f in config_files if f.strip()]
+
+    def get_standard_config_settings(self):
+        settings = Values()
+        for filename in self.get_standard_config_files():
+            settings.update(self.get_config_file_settings(filename), self)
+        return settings
+
+    def get_config_file_settings(self, config_file):
+        """Returns a dictionary containing appropriate config file settings."""
+        parser = ConfigParser()
+        parser.read(config_file, self)
+        self.config_files.extend(parser._files)
+        base_path = os.path.dirname(config_file)
+        applied = {}
+        settings = Values()
+        for component in self.components:
+            if not component:
+                continue
+            for section in (tuple(component.config_section_dependencies or ())
+                            + (component.config_section,)):
+                if section in applied:
+                    continue
+                applied[section] = 1
+                settings.update(parser.get_section(section), self)
+        make_paths_absolute(
+            settings.__dict__, self.relative_path_settings, base_path)
+        return settings.__dict__
+
+    def check_values(self, values, args):
+        """Store positional arguments as runtime settings."""
+        values._source, values._destination = self.check_args(args)
+        make_paths_absolute(values.__dict__, self.relative_path_settings)
+        values._config_files = self.config_files
+        return values
+
+    def check_args(self, args):
+        source = destination = None
+        if args:
+            source = args.pop(0)
+            if source == '-':           # means stdin
+                source = None
+        if args:
+            destination = args.pop(0)
+            if destination == '-':      # means stdout
+                destination = None
+        if args:
+            self.error('Maximum 2 arguments allowed.')
+        if source and source == destination:
+            self.error('Do not specify the same file for both source and '
+                       'destination.  It will clobber the source file.')
+        return source, destination
+
+    def set_defaults_from_dict(self, defaults):
+        self.defaults.update(defaults)
+
+    def get_default_values(self):
+        """Needed to get custom `Values` instances."""
+        defaults = Values(self.defaults)
+        defaults._config_files = self.config_files
+        return defaults
+
+    def get_option_by_dest(self, dest):
+        """
+        Get an option by its dest.
+
+        If you're supplying a dest which is shared by several options,
+        it is undefined which option of those is returned.
+
+        A KeyError is raised if there is no option with the supplied
+        dest.
+        """
+        for group in self.option_groups + [self]:
+            for option in group.option_list:
+                if option.dest == dest:
+                    return option
+        raise KeyError('No option with dest == %r.' % dest)
+
+
+class ConfigParser(RawConfigParser):
+
+    old_settings = {
+        'pep_stylesheet': ('pep_html writer', 'stylesheet'),
+        'pep_stylesheet_path': ('pep_html writer', 'stylesheet_path'),
+        'pep_template': ('pep_html writer', 'template')}
+    """{old setting: (new section, new setting)} mapping, used by
+    `handle_old_config`, to convert settings from the old [options] section."""
+
+    old_warning = """
+The "[option]" section is deprecated.  Support for old-format configuration
+files may be removed in a future Docutils release.  Please revise your
+configuration files.  See <http://docutils.sf.net/docs/user/config.html>,
+section "Old-Format Configuration Files".
+"""
+
+    not_utf8_error = """\
+Unable to read configuration file "%s": content not encoded as UTF-8.
+Skipping "%s" configuration file.
+"""
+
+    def __init__(self, *args, **kwargs):
+        RawConfigParser.__init__(self, *args, **kwargs)
+
+        self._files = []
+        """List of paths of configuration files read."""
+
+        self._stderr = ErrorOutput()
+        """Wrapper around sys.stderr catching en-/decoding errors"""
+
+    def read(self, filenames, option_parser):
+        if type(filenames) in (str, unicode):
+            filenames = [filenames]
+        for filename in filenames:
+            try:
+                # Config files must be UTF-8-encoded:
+                fp = codecs.open(filename, 'r', 'utf-8')
+            except IOError:
+                continue
+            try:
+                if sys.version_info < (3, 0):
+                    RawConfigParser.readfp(self, fp, filename)
+                else:
+                    RawConfigParser.read_file(self, fp, filename)
+            except UnicodeDecodeError:
+                self._stderr.write(self.not_utf8_error % (filename, filename))
+                fp.close()
+                continue
+            fp.close()
+            self._files.append(filename)
+            if self.has_section('options'):
+                self.handle_old_config(filename)
+            self.validate_settings(filename, option_parser)
+
+    def handle_old_config(self, filename):
+        warnings.warn_explicit(self.old_warning, ConfigDeprecationWarning,
+                               filename, 0)
+        options = self.get_section('options')
+        if not self.has_section('general'):
+            self.add_section('general')
+        for key, value in options.items():
+            if key in self.old_settings:
+                section, setting = self.old_settings[key]
+                if not self.has_section(section):
+                    self.add_section(section)
+            else:
+                section = 'general'
+                setting = key
+            if not self.has_option(section, setting):
+                self.set(section, setting, value)
+        self.remove_section('options')
+
+    def validate_settings(self, filename, option_parser):
+        """
+        Call the validator function and implement overrides on all applicable
+        settings.
+        """
+        for section in self.sections():
+            for setting in self.options(section):
+                try:
+                    option = option_parser.get_option_by_dest(setting)
+                except KeyError:
+                    continue
+                if option.validator:
+                    value = self.get(section, setting)
+                    try:
+                        new_value = option.validator(
+                            setting, value, option_parser,
+                            config_parser=self, config_section=section)
+                    except Exception as error:
+                        raise ValueError(
+                            'Error in config file "%s", section "[%s]":\n'
+                            '    %s\n'
+                            '        %s = %s'
+                            % (filename, section, ErrorString(error),
+                               setting, value))
+                    self.set(section, setting, new_value)
+                if option.overrides:
+                    self.set(section, option.overrides, None)
+
+    def optionxform(self, optionstr):
+        """
+        Transform '-' to '_' so the cmdline form of option names can be used.
+        """
+        return optionstr.lower().replace('-', '_')
+
+    def get_section(self, section):
+        """
+        Return a given section as a dictionary (empty if the section
+        doesn't exist).
+        """
+        section_dict = {}
+        if self.has_section(section):
+            for option in self.options(section):
+                section_dict[option] = self.get(section, option)
+        return section_dict
+
+
+class ConfigDeprecationWarning(DeprecationWarning):
+    """Warning for deprecated configuration file features."""