Source code for betty.locale.localizable

"""
The localizable API allows objects to be localized at the point of use.
"""

from abc import ABC, abstractmethod
from collections.abc import Callable, Mapping, Sequence
from typing import Any, cast, TypeAlias
from warnings import warn

from betty.locale import negotiate_locale, to_locale
from betty.locale.localizer import DEFAULT_LOCALIZER
from betty.locale.localizer import Localizer
from typing_extensions import override


[docs] class Localizable(ABC): """ A localizable object. Objects of this type can convert themselves to localized strings at the point of use. """
[docs] @abstractmethod def localize(self, localizer: Localizer) -> str: """ Localize ``self`` to a human-readable string. """ pass
@override def __str__(self) -> str: localized = self.localize(DEFAULT_LOCALIZER) warn( f'{type(self)} ("{localized}") SHOULD NOT be cast to a string. Instead, call {type(self)}.localize() to ensure it is always formatted in the desired locale.', stacklevel=2, ) return localized
class _FormattableLocalizable(Localizable): def format( self, *format_args: str | Localizable, **format_kwargs: str | Localizable ) -> Localizable: return format(self, **format_kwargs) class _CallLocalizable(Localizable): def __init__(self, call: Callable[[Localizer], str]): self._call = call @override def localize(self, localizer: Localizer) -> str: return self._call(localizer)
[docs] def call(call: Callable[[Localizer], str]) -> Localizable: """ Create a new localizable that outputs the callable's return value. """ return _CallLocalizable(call)
class _GettextLocalizable(_FormattableLocalizable): def __init__( self, gettext_method_name: str, *gettext_args: Any, ) -> None: self._gettext_method_name = gettext_method_name self._gettext_args = gettext_args @override def localize(self, localizer: Localizer) -> str: return cast( str, getattr(localizer, self._gettext_method_name)(*self._gettext_args) )
[docs] def gettext(message: str) -> _GettextLocalizable: """ Like :py:meth:`gettext.gettext`. Positional arguments are identical to those of :py:meth:`gettext.gettext`. Keyword arguments are identical to those of :py:met:`str.format`, except that any :py:class:`betty.locale.Localizable` will be localized before string formatting. """ return _GettextLocalizable("gettext", message)
def _(message: str) -> _GettextLocalizable: """ Like :py:meth:`gettext._` and :py:meth:`betty.locale.localizable.gettext`. Positional arguments are identical to those of :py:meth:`gettext.gettext`. Keyword arguments are identical to those of :py:met:`str.format`, except that any :py:class:`betty.locale.Localizable` will be localized before string formatting. """ return gettext(message)
[docs] def ngettext(message_singular: str, message_plural: str, n: int) -> _GettextLocalizable: """ Like :py:meth:`gettext.ngettext`. Positional arguments are identical to those of :py:meth:`gettext.ngettext`. Keyword arguments are identical to those of :py:met:`str.format`, except that any :py:class:`betty.locale.Localizable` will be localized before string formatting. """ return _GettextLocalizable("ngettext", message_singular, message_plural, n)
[docs] def pgettext(context: str, message: str) -> _GettextLocalizable: """ Like :py:meth:`gettext.pgettext`. Positional arguments are identical to those of :py:meth:`gettext.pgettext`. Keyword arguments are identical to those of :py:met:`str.format`, except that any :py:class:`betty.locale.Localizable` will be localized before string formatting. """ return _GettextLocalizable("pgettext", context, message)
[docs] def npgettext( context: str, message_singular: str, message_plural: str, n: int ) -> _GettextLocalizable: """ Like :py:meth:`gettext.npgettext`. Positional arguments are identical to those of :py:meth:`gettext.npgettext`. Keyword arguments are identical to those of :py:met:`str.format`, except that any :py:class:`betty.locale.Localizable` will be localized before string formatting. """ return _GettextLocalizable( "npgettext", context, message_singular, message_plural, n )
class _FormattedLocalizable(Localizable): def __init__( self, localizable: Localizable, format_args: Sequence[str | Localizable], format_kwargs: Mapping[str, str | Localizable], ): self._localizable = localizable self._format_args = format_args self._format_kwargs = format_kwargs @override def localize(self, localizer: Localizer) -> str: return self._localizable.localize(localizer).format( *( format_arg.localize(localizer) if isinstance(format_arg, Localizable) else format_arg for format_arg in self._format_args ), **{ format_kwarg_key: format_kwarg.localize(localizer) if isinstance(format_kwarg, Localizable) else format_kwarg for format_kwarg_key, format_kwarg in self._format_kwargs.items() }, )
[docs] def format( # noqa A001 localizable: Localizable, *format_args: str | Localizable, **format_kwargs: str | Localizable, ) -> Localizable: """ Perform string formatting. The arguments are identical to those of :py:meth:``str.format``. """ return _FormattedLocalizable(localizable, format_args, format_kwargs)
StaticTranslations: TypeAlias = Mapping[str, str] """ Keys are locales, values are translations. See :py:func:`betty.locale.localizable.assertion.assert_static_translations`. """ ShorthandStaticTranslations: TypeAlias = StaticTranslations | str """ :py:const:`StaticTranslations` or a string which is the translation for the undetermined locale. See :py:func:`betty.locale.localizable.assertion.assert_static_translations`. """
[docs] class StaticTranslationsLocalizable(_FormattableLocalizable): """ Provide a :py:class:`betty.locale.Localizable` backed by static translations. """
[docs] def __init__(self, translations: ShorthandStaticTranslations): if isinstance(translations, Mapping) and len(translations) < 1: raise ValueError("At least one translation must be provided") self._translations: ShorthandStaticTranslations = translations
[docs] @override def localize(self, localizer: Localizer) -> str: if isinstance(self._translations, str): return self._translations if len(self._translations) > 1: available_locales = tuple(self._translations.keys()) requested_locale = to_locale( ( negotiate_locale(localizer.locale, available_locales) or available_locales[0] ) ) if requested_locale: return self._translations[requested_locale] return next(iter(self._translations.values()))
[docs] def static(translations: ShorthandStaticTranslations) -> Localizable: """ Create a new localizable that outputs the given static translations. """ from betty.locale.localizable.assertion import assert_static_translations return StaticTranslationsLocalizable(assert_static_translations()(translations))