diff options
Diffstat (limited to 'babel/support.py')
| -rw-r--r-- | babel/support.py | 398 |
1 files changed, 398 insertions, 0 deletions
diff --git a/babel/support.py b/babel/support.py new file mode 100644 index 0000000..74f7162 --- /dev/null +++ b/babel/support.py @@ -0,0 +1,398 @@ +# -*- coding: utf-8 -*- +# +# Copyright (C) 2007 Edgewall Software +# All rights reserved. +# +# This software is licensed as described in the file COPYING, which +# you should have received as part of this distribution. The terms +# are also available at http://babel.edgewall.org/wiki/License. +# +# This software consists of voluntary contributions made by many +# individuals. For the exact contribution history, see the revision +# history and logs, available at http://babel.edgewall.org/log/. + +"""Several classes and functions that help with integrating and using Babel +in applications. + +.. note: the code in this module is not used by Babel itself +""" + +from datetime import date, datetime, time +import gettext + +try: + set +except NameError: + from sets import set + +from babel.core import Locale +from babel.dates import format_date, format_datetime, format_time, LC_TIME +from babel.numbers import format_number, format_decimal, format_currency, \ + format_percent, format_scientific, LC_NUMERIC +from babel.util import UTC + +__all__ = ['Format', 'LazyProxy', 'Translations'] +__docformat__ = 'restructuredtext en' + + +class Format(object): + """Wrapper class providing the various date and number formatting functions + bound to a specific locale and time-zone. + + >>> fmt = Format('en_US', UTC) + >>> fmt.date(date(2007, 4, 1)) + u'Apr 1, 2007' + >>> fmt.decimal(1.2345) + u'1.234' + """ + + def __init__(self, locale, tzinfo=None): + """Initialize the formatter. + + :param locale: the locale identifier or `Locale` instance + :param tzinfo: the time-zone info (a `tzinfo` instance or `None`) + """ + self.locale = Locale.parse(locale) + self.tzinfo = tzinfo + + def date(self, date=None, format='medium'): + """Return a date formatted according to the given pattern. + + >>> fmt = Format('en_US') + >>> fmt.date(date(2007, 4, 1)) + u'Apr 1, 2007' + + :see: `babel.dates.format_date` + """ + return format_date(date, format, locale=self.locale) + + def datetime(self, datetime=None, format='medium'): + """Return a date and time formatted according to the given pattern. + + >>> from pytz import timezone + >>> fmt = Format('en_US', tzinfo=timezone('US/Eastern')) + >>> fmt.datetime(datetime(2007, 4, 1, 15, 30)) + u'Apr 1, 2007 11:30:00 AM' + + :see: `babel.dates.format_datetime` + """ + return format_datetime(datetime, format, tzinfo=self.tzinfo, + locale=self.locale) + + def time(self, time=None, format='medium'): + """Return a time formatted according to the given pattern. + + >>> from pytz import timezone + >>> fmt = Format('en_US', tzinfo=timezone('US/Eastern')) + >>> fmt.time(datetime(2007, 4, 1, 15, 30)) + u'11:30:00 AM' + + :see: `babel.dates.format_time` + """ + return format_time(time, format, tzinfo=self.tzinfo, locale=self.locale) + + def number(self, number): + """Return an integer number formatted for the locale. + + >>> fmt = Format('en_US') + >>> fmt.number(1099) + u'1,099' + + :see: `babel.numbers.format_number` + """ + return format_number(number, locale=self.locale) + + def decimal(self, number, format=None): + """Return a decimal number formatted for the locale. + + >>> fmt = Format('en_US') + >>> fmt.decimal(1.2345) + u'1.234' + + :see: `babel.numbers.format_decimal` + """ + return format_decimal(number, format, locale=self.locale) + + def currency(self, number, currency): + """Return a number in the given currency formatted for the locale. + + :see: `babel.numbers.format_currency` + """ + return format_currency(number, currency, locale=self.locale) + + def percent(self, number, format=None): + """Return a number formatted as percentage for the locale. + + >>> fmt = Format('en_US') + >>> fmt.percent(0.34) + u'34%' + + :see: `babel.numbers.format_percent` + """ + return format_percent(number, format, locale=self.locale) + + def scientific(self, number): + """Return a number formatted using scientific notation for the locale. + + :see: `babel.numbers.format_scientific` + """ + return format_scientific(number, locale=self.locale) + + +class LazyProxy(object): + """Class for proxy objects that delegate to a specified function to evaluate + the actual object. + + >>> def greeting(name='world'): + ... return 'Hello, %s!' % name + >>> lazy_greeting = LazyProxy(greeting, name='Joe') + >>> print lazy_greeting + Hello, Joe! + >>> u' ' + lazy_greeting + u' Hello, Joe!' + >>> u'(%s)' % lazy_greeting + u'(Hello, Joe!)' + + This can be used, for example, to implement lazy translation functions that + delay the actual translation until the string is actually used. The + rationale for such behavior is that the locale of the user may not always + be available. In web applications, you only know the locale when processing + a request. + + The proxy implementation attempts to be as complete as possible, so that + the lazy objects should mostly work as expected, for example for sorting: + + >>> greetings = [ + ... LazyProxy(greeting, 'world'), + ... LazyProxy(greeting, 'Joe'), + ... LazyProxy(greeting, 'universe'), + ... ] + >>> greetings.sort() + >>> for greeting in greetings: + ... print greeting + Hello, Joe! + Hello, universe! + Hello, world! + """ + __slots__ = ['_func', '_args', '_kwargs', '_value'] + + def __init__(self, func, *args, **kwargs): + # Avoid triggering our own __setattr__ implementation + object.__setattr__(self, '_func', func) + object.__setattr__(self, '_args', args) + object.__setattr__(self, '_kwargs', kwargs) + object.__setattr__(self, '_value', None) + + def value(self): + if self._value is None: + value = self._func(*self._args, **self._kwargs) + object.__setattr__(self, '_value', value) + return self._value + value = property(value) + + def __contains__(self, key): + return key in self.value + + def __nonzero__(self): + return bool(self.value) + + def __dir__(self): + return dir(self.value) + + def __iter__(self): + return iter(self.value) + + def __len__(self): + return len(self.value) + + def __str__(self): + return str(self.value) + + def __unicode__(self): + return unicode(self.value) + + def __add__(self, other): + return self.value + other + + def __radd__(self, other): + return other + self.value + + def __mod__(self, other): + return self.value % other + + def __rmod__(self, other): + return other % self.value + + def __mul__(self, other): + return self.value * other + + def __rmul__(self, other): + return other * self.value + + def __call__(self, *args, **kwargs): + return self.value(*args, **kwargs) + + def __lt__(self, other): + return self.value < other + + def __le__(self, other): + return self.value <= other + + def __eq__(self, other): + return self.value == other + + def __ne__(self, other): + return self.value != other + + def __gt__(self, other): + return self.value > other + + def __ge__(self, other): + return self.value >= other + + def __delattr__(self, name): + delattr(self.value, name) + + def __getattr__(self, name): + return getattr(self.value, name) + + def __setattr__(self, name, value): + setattr(self.value, name, value) + + def __delitem__(self, key): + del self.value[key] + + def __getitem__(self, key): + return self.value[key] + + def __setitem__(self, key, value): + self.value[key] = value + + +class Translations(gettext.GNUTranslations, object): + """An extended translation catalog class.""" + + DEFAULT_DOMAIN = 'messages' + + def __init__(self, fileobj=None, domain=DEFAULT_DOMAIN): + """Initialize the translations catalog. + + :param fileobj: the file-like object the translation should be read + from + """ + gettext.GNUTranslations.__init__(self, fp=fileobj) + self.files = filter(None, [getattr(fileobj, 'name', None)]) + self.domain = domain + self._domains = {} + + def load(cls, dirname=None, locales=None, domain=DEFAULT_DOMAIN): + """Load translations from the given directory. + + :param dirname: the directory containing the ``MO`` files + :param locales: the list of locales in order of preference (items in + this list can be either `Locale` objects or locale + strings) + :param domain: the message domain + :return: the loaded catalog, or a ``NullTranslations`` instance if no + matching translations were found + :rtype: `Translations` + """ + if locales is not None: + if not isinstance(locales, (list, tuple)): + locales = [locales] + locales = [str(locale) for locale in locales] + if not domain: + domain = cls.DEFAULT_DOMAIN + filename = gettext.find(domain, dirname, locales) + if not filename: + return gettext.NullTranslations() + return cls(fileobj=open(filename, 'rb'), domain=domain) + load = classmethod(load) + + def __repr__(self): + return '<%s: "%s">' % (type(self).__name__, + self._info.get('project-id-version')) + + def add(self, translations, merge=True): + """Add the given translations to the catalog. + + If the domain of the translations is different than that of the + current catalog, they are added as a catalog that is only accessible + by the various ``d*gettext`` functions. + + :param translations: the `Translations` instance with the messages to + add + :param merge: whether translations for message domains that have + already been added should be merged with the existing + translations + :return: the `Translations` instance (``self``) so that `merge` calls + can be easily chained + :rtype: `Translations` + """ + domain = getattr(translations, 'domain', self.DEFAULT_DOMAIN) + if merge and domain == self.domain: + return self.merge(translations) + + existing = self._domains.get(domain) + if merge and existing is not None: + existing.merge(translations) + else: + translations.add_fallback(self) + self._domains[domain] = translations + + return self + + def merge(self, translations): + """Merge the given translations into the catalog. + + Message translations in the specified catalog override any messages + with the same identifier in the existing catalog. + + :param translations: the `Translations` instance with the messages to + merge + :return: the `Translations` instance (``self``) so that `merge` calls + can be easily chained + :rtype: `Translations` + """ + if isinstance(translations, gettext.GNUTranslations): + self._catalog.update(translations._catalog) + if isinstance(translations, Translations): + self.files.extend(translations.files) + + return self + + def dgettext(self, domain, message): + """Like ``gettext()``, but look the message up in the specified + domain. + """ + return self._domains.get(domain, self).gettext(message) + + def ldgettext(self, domain, message): + """Like ``lgettext()``, but look the message up in the specified + domain. + """ + return self._domains.get(domain, self).lgettext(message) + + def dugettext(self, domain, message): + """Like ``ugettext()``, but look the message up in the specified + domain. + """ + return self._domains.get(domain, self).ugettext(message) + + def dngettext(self, domain, singular, plural, num): + """Like ``ngettext()``, but look the message up in the specified + domain. + """ + return self._domains.get(domain, self).ngettext(singular, plural, num) + + def ldngettext(self, domain, singular, plural, num): + """Like ``lngettext()``, but look the message up in the specified + domain. + """ + return self._domains.get(domain, self).lngettext(singular, plural, num) + + def dungettext(self, domain, singular, plural, num): + """Like ``ungettext()`` but look the message up in the specified + domain. + """ + return self._domains.get(domain, self).ungettext(singular, plural, num) |