74 lines
2.4 KiB
Python
74 lines
2.4 KiB
Python
# -*- coding: utf-8 -*-
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try:
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from functools import total_ordering
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except ImportError:
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""" Backport to work with Python 2.6 """
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def total_ordering(cls):
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"""Class decorator that fills in missing ordering methods"""
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convert = {
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'__lt__': [
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(
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'__gt__',
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lambda self, other: not (self < other or self == other)
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),
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(
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'__le__',
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lambda self, other: self < other or self == other
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),
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(
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'__ge__',
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lambda self, other: not self < other
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)],
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'__le__': [
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(
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'__ge__',
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lambda self, other: not self <= other or self == other
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),
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(
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'__lt__',
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lambda self, other: self <= other and not self == other
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),
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(
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'__gt__',
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lambda self, other: not self <= other
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)],
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'__gt__': [
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(
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'__lt__',
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lambda self, other: not (self > other or self == other)
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),
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(
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'__ge__',
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lambda self, other: self > other or self == other
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),
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(
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'__le__',
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lambda self, other: not self > other
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)],
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'__ge__': [
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(
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'__le__',
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lambda self, other: (not self >= other) or self == other
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),
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(
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'__gt__',
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lambda self, other: self >= other and not self == other
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),
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(
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'__lt__',
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lambda self, other: not self >= other
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)]
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}
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roots = set(dir(cls)) & set(convert)
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if not roots:
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raise ValueError(
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'must define at least one ordering operation: < > <= >='
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)
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root = max(roots) # prefer __lt__ to __le__ to __gt__ to __ge__
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for opname, opfunc in convert[root]:
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if opname not in roots:
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opfunc.__name__ = opname
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opfunc.__doc__ = getattr(int, opname).__doc__
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setattr(cls, opname, opfunc)
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return cls
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