from .. import i18n, ImproperlyConfigured
from ..utils import str_coercible
[docs]@str_coercible
class Currency:
"""
Currency class wraps a 3-letter currency code. It provides various
convenience properties and methods.
::
from babel import Locale
from sqlalchemy_utils import Currency, i18n
# First lets add a locale getter for testing purposes
i18n.get_locale = lambda: Locale('en')
Currency('USD').name # US Dollar
Currency('USD').symbol # $
Currency(Currency('USD')).code # 'USD'
Currency always validates the given code if you use at least the optional
dependency list 'babel', otherwise no validation are performed.
::
Currency(None) # raises TypeError
Currency('UnknownCode') # raises ValueError
Currency supports equality operators.
::
Currency('USD') == Currency('USD')
Currency('USD') != Currency('EUR')
Currencies are hashable.
::
len(set([Currency('USD'), Currency('USD')])) # 1
"""
def __init__(self, code):
if i18n.babel is None:
raise ImproperlyConfigured(
"'babel' package is required in order to use Currency class."
)
if isinstance(code, Currency):
self.code = code
elif isinstance(code, str):
self.validate(code)
self.code = code
else:
raise TypeError(
'First argument given to Currency constructor should be '
'either an instance of Currency or valid three letter '
'currency code.'
)
@classmethod
def validate(self, code):
try:
i18n.babel.Locale('en').currencies[code]
except KeyError:
raise ValueError(f"'{code}' is not valid currency code.")
except AttributeError:
# As babel is optional, we may raise an AttributeError accessing it
pass
@property
def symbol(self):
return i18n.babel.numbers.get_currency_symbol(
self.code,
i18n.get_locale()
)
@property
def name(self):
return i18n.get_locale().currencies[self.code]
def __eq__(self, other):
if isinstance(other, Currency):
return self.code == other.code
elif isinstance(other, str):
return self.code == other
else:
return NotImplemented
def __ne__(self, other):
return not (self == other)
def __hash__(self):
return hash(self.code)
def __repr__(self):
return f'{self.__class__.__name__}({self.code!r})'
def __unicode__(self):
return self.code