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"""sets module
This module provides some Set classes for dealing with MySQL data.
"""
class Set:
"""A simple class for handling sets. Sets are immutable in the same
way numbers are."""
def __init__(self, *values):
"""Use values to initialize the Set."""
self._values = values
def __contains__(self, value):
return value in self._values and 1 or 0
def __str__(self):
"""Returns the values as a comma-separated string."""
return ','.join([ str(x) for x in self._values])
def __repr__(self):
return "%s%s" % (self.__class__.__name__, `self._values`)
def __or__(self, other):
"""Union."""
values = list(self._values)
if isinstance(other, Set):
for v in other._values:
if v not in values:
values.append(v)
elif other not in self._values:
values.append(other)
return self.__class__(*values)
__add__ = __or__
def __sub__(self, other):
values = list(self._values)
if isinstance(other, Set):
for v in other._values:
if v in values:
values.remove(v)
elif other in self:
values.remove(other)
return self.__class__(*values)
def __and__(self, other):
"Intersection."
values = []
if isinstance(other, Set):
for v in self._values:
if v in other:
values.append(v)
elif other in self:
values.append(other)
return self.__class__(*values)
__mul__ = __and__
def __xor__(self, other):
"Intersection's complement."
return (self|other)-(self&other)
def __getitem__(self, n):
return self._values[n]
def __getslice__(self, n1, n2):
return self._values[n1:n2]
def __len__(self):
return len(self._values)
def __hash__(self):
return hash(self._values)
def __cmp__(self, other):
if isinstance(other, Set):
if not self ^ other:
return 0
elif self & other == self:
return 1
else:
return -1
elif other in self._values:
return 0
elif other > self._values:
return 1
else:
return -1
# rich comparison operators for Python 2.1 and up
def __ne__(self, other):
return self ^ other
def __eq__(self, other):
if not self != other:
return self
else:
return self.__class__()
def __le__(self, other):
return self & other == self
def __lt__(self, other):
if self <= other and self ^ other:
return self
else:
return self.__class__()
def __ge__(self, other):
return self & other == other
def __gt__(self, other):
if self >= other and self ^ other:
return self
else:
return self.__class__()
class DBAPISet(Set):
"""A special type of set for which A == x is true if A is a
DBAPISet and x is a member of that set."""
# Note that Set.__cmp__ works perfectly well in this case, if
# we are using < Python 2.1. It's just broken for <, >, etc.
def __ne__(self, other):
if isinstance(other, Set): # yes, Set
return self % other
elif other in self._values:
return 0
else:
return 1
def __eq__(self, other):
if self != other:
return self.__class__()
else:
return self
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