# -*- coding: utf-8 -*-
"""
    pygments.util
    ~~~~~~~~~~~~~

    Utility functions, currently only for parsing lexer
    and formatter options.

    :copyright: 2006 by Georg Brandl.
    :license: GNU LGPL, see LICENSE for more details.
"""


class OptionError(Exception):
    pass


def get_bool_opt(options, optname, default=None):
    string = options.get(optname, default)
    if isinstance(string, bool):
        return string
    elif string.lower() in ('1', 'yes', 'true', 'on'):
        return True
    elif string.lower() in ('0', 'no', 'false', 'off'):
        return False
    else:
        raise OptionError('Invalid value %r for option %s; use '
                          '1/0, yes/no, true/false, on/off' %
                          string, optname)


def get_int_opt(options, optname, default=None):
    string = options.get(optname, default)
    try:
        return int(string)
    except ValueError:
        raise OptionError('Invalid value %r for option %s; you '
                          'must give an integer value' %
                          string, optname)


def get_list_opt(options, optname, default=None):
    val = options.get(optname, default)
    if isinstance(val, basestring):
        return val.split()
    elif isinstance(val, (list, tuple)):
        return list(val)
    else:
        raise OptionError('Invalid value %r for option %s; you '
                          'must give a list value' %
                          val, optname)