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Diffstat (limited to 'engine/SCons/compat/_scons_sets15.py')
-rw-r--r-- | engine/SCons/compat/_scons_sets15.py | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/engine/SCons/compat/_scons_sets15.py b/engine/SCons/compat/_scons_sets15.py new file mode 100644 index 0000000..bafa009 --- /dev/null +++ b/engine/SCons/compat/_scons_sets15.py @@ -0,0 +1,176 @@ +# +# A Set class that works all the way back to Python 1.5. From: +# +# Python Cookbook: Yet another Set class for Python +# http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/106469 +# Goncalo Rodriques +# +# This is a pure Pythonic implementation of a set class. The syntax +# and methods implemented are, for the most part, borrowed from +# PEP 218 by Greg Wilson. +# +# Note that this class violates the formal definition of a set() by adding +# a __getitem__() method so we can iterate over a set's elements under +# Python 1.5 and 2.1, which don't support __iter__() and iterator types. +# + +import string + +class Set: + """The set class. It can contain mutable objects.""" + + def __init__(self, seq = None): + """The constructor. It can take any object giving an iterator as an optional + argument to populate the new set.""" + self.elems = [] + if seq: + for elem in seq: + if elem not in self.elems: + hash(elem) + self.elems.append(elem) + + def __str__(self): + return "set([%s])" % string.join(map(str, self.elems), ", ") + + + def copy(self): + """Shallow copy of a set object.""" + return Set(self.elems) + + def __contains__(self, elem): + return elem in self.elems + + def __len__(self): + return len(self.elems) + + def __getitem__(self, index): + # Added so that Python 1.5 can iterate over the elements. + # The cookbook recipe's author didn't like this because there + # really isn't any order in a set object, but this is necessary + # to make the class work well enough for our purposes. + return self.elems[index] + + def items(self): + """Returns a list of the elements in the set.""" + return self.elems + + def add(self, elem): + """Add one element to the set.""" + if elem not in self.elems: + hash(elem) + self.elems.append(elem) + + def remove(self, elem): + """Remove an element from the set. Return an error if elem is not in the set.""" + try: + self.elems.remove(elem) + except ValueError: + raise LookupError, "Object %s is not a member of the set." % str(elem) + + def discard(self, elem): + """Remove an element from the set. Do nothing if elem is not in the set.""" + try: + self.elems.remove(elem) + except ValueError: + pass + + def sort(self, func=cmp): + self.elems.sort(func) + + #Define an iterator for a set. + def __iter__(self): + return iter(self.elems) + + #The basic binary operations with sets. + def __or__(self, other): + """Union of two sets.""" + ret = self.copy() + for elem in other.elems: + if elem not in ret: + ret.elems.append(elem) + return ret + + def __sub__(self, other): + """Difference of two sets.""" + ret = self.copy() + for elem in other.elems: + ret.discard(elem) + return ret + + def __and__(self, other): + """Intersection of two sets.""" + ret = Set() + for elem in self.elems: + if elem in other.elems: + ret.elems.append(elem) + return ret + + def __add__(self, other): + """Symmetric difference of two sets.""" + ret = Set() + temp = other.copy() + for elem in self.elems: + if elem in temp.elems: + temp.elems.remove(elem) + else: + ret.elems.append(elem) + #Add remaining elements. + for elem in temp.elems: + ret.elems.append(elem) + return ret + + def __mul__(self, other): + """Cartesian product of two sets.""" + ret = Set() + for elemself in self.elems: + x = map(lambda other, s=elemself: (s, other), other.elems) + ret.elems.extend(x) + return ret + + #Some of the binary comparisons. + def __lt__(self, other): + """Returns 1 if the lhs set is contained but not equal to the rhs set.""" + if len(self.elems) < len(other.elems): + temp = other.copy() + for elem in self.elems: + if elem in temp.elems: + temp.remove(elem) + else: + return 0 + return len(temp.elems) == 0 + else: + return 0 + + def __le__(self, other): + """Returns 1 if the lhs set is contained in the rhs set.""" + if len(self.elems) <= len(other.elems): + ret = 1 + for elem in self.elems: + if elem not in other.elems: + ret = 0 + break + return ret + else: + return 0 + + def __eq__(self, other): + """Returns 1 if the sets are equal.""" + if len(self.elems) != len(other.elems): + return 0 + else: + return len(self - other) == 0 + + def __cmp__(self, other): + """Returns 1 if the sets are equal.""" + if self.__lt__(other): + return -1 + elif other.__lt__(self): + return 1 + else: + return 0 + +# Local Variables: +# tab-width:4 +# indent-tabs-mode:nil +# End: +# vim: set expandtab tabstop=4 shiftwidth=4: |