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class Comparable:
"""Customise how your Enum acts when compared to other objects.
Your Enum must implement a ``_cmp_values`` method which takes the Enum
member's value and the other value and manipulates them into the actual
values that can be compared.
A case-insensitive StrEnum might look like this::
class HttpHeader(Comparable, KebabCaseStrEnum):
ContentType = auto()
Host = auto()
Accept = auto()
XForwardedFor = auto()
def _cmp_values(self, other):
return self.value.lower(), str(other).lower()
You could then use these headers in case-insensitive comparisons::
assert "Content-Type" == HttpHeader.ContentType
assert "content-type" == HttpHeader.ContentType
assert "coNtEnt-tyPe" == HttpHeader.ContentType
.. note::
Your ``_cmp_values`` method *must not* return ``self`` as one of the
values to be compared -- that would result in infinite recursion.
Instead, perform operations on ``self.value`` and return that.
.. warning::
A bug in Python prior to 3.7.1 prevents mix-ins working with Enum
subclasses.
.. versionadded:: 0.4.6
"""
def __eq__(self, other):
value, other = self._cmp_values(other)
return value == other
def __ne__(self, other):
value, other = self._cmp_values(other)
return value != other
def __lt__(self, other):
value, other = self._cmp_values(other)
return value < other
def __le__(self, other):
value, other = self._cmp_values(other)
return value <= other
def __gt__(self, other):
value, other = self._cmp_values(other)
return value > other
def __ge__(self, other):
value, other = self._cmp_values(other)
return value >= other
def _cmp_values(self, other):
raise NotImplementedError(
"Enum's using Comparable must implement their own _cmp_values function."
)
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