Source Code for Module SCons.compat._scons_sets15

  1  # 
  2  # A Set class that works all the way back to Python 1.5.  From: 
  3  # 
  4  #       Python Cookbook:  Yet another Set class for Python 
  5  #       http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/106469 
  6  #       Goncalo Rodriques 
  7  # 
  8  #       This is a pure Pythonic implementation of a set class.  The syntax 
  9  #       and methods implemented are, for the most part, borrowed from 
 10  #       PEP 218 by Greg Wilson. 
 11  # 
 12  # Note that this class violates the formal definition of a set() by adding 
 13  # a __getitem__() method so we can iterate over a set's elements under 
 14  # Python 1.5 and 2.1, which don't support __iter__() and iterator types. 
 15  # 
 16   
 17  import string 
 18   
 19 -class Set: 
 20      """The set class. It can contain mutable objects.""" 
 21   
 22 -    def __init__(self, seq = None): 
 23          """The constructor. It can take any object giving an iterator as an optional 
 24          argument to populate the new set.""" 
 25          self.elems = [] 
 26          if seq: 
 27              for elem in seq: 
 28                  if elem not in self.elems: 
 29                      self.elems.append(elem) 
 30   
 31 -    def __str__(self): 
 32          return "{%s}" % string.join(map(str, self.elems), ", ") 
 33   
 34   
 35 -    def copy(self): 
 36          """Shallow copy of a set object.""" 
 37          return Set(self.elems) 
 38   
 39 -    def __contains__(self, elem): 
 40          return elem in self.elems 
 41   
 42 -    def __len__(self): 
 43          return len(self.elems) 
 44   
 45 -    def __getitem__(self, index): 
 46          # Added so that Python 1.5 can iterate over the elements. 
 47          # The cookbook recipe's author didn't like this because there 
 48          # really isn't any order in a set object, but this is necessary 
 49          # to make the class work well enough for our purposes. 
 50          return self.elems[index] 
 51   
 52 -    def items(self): 
 53          """Returns a list of the elements in the set.""" 
 54          return self.elems 
 55   
 56 -    def add(self, elem): 
 57          """Add one element to the set.""" 
 58          if elem not in self.elems: 
 59              self.elems.append(elem) 
 60   
 61 -    def remove(self, elem): 
 62          """Remove an element from the set. Return an error if elem is not in the set.""" 
 63          try: 
 64              self.elems.remove(elem) 
 65          except ValueError: 
 66              raise LookupError, "Object %s is not a member of the set." % str(elem) 
 67   
 68 -    def discard(self, elem): 
 69          """Remove an element from the set. Do nothing if elem is not in the set.""" 
 70          try: 
 71              self.elems.remove(elem) 
 72          except ValueError: 
 73              pass 
 74   
 75 -    def sort(self, func=cmp): 
 76          self.elems.sort(func) 
 77   
 78      #Define an iterator for a set. 
 79 -    def __iter__(self): 
 80          return iter(self.elems) 
 81   
 82      #The basic binary operations with sets. 
 83 -    def __or__(self, other): 
 84          """Union of two sets.""" 
 85          ret = self.copy() 
 86          for elem in other.elems: 
 87              if elem not in ret: 
 88                  ret.elems.append(elem) 
 89          return ret 
 90   
 91 -    def __sub__(self, other): 
 92          """Difference of two sets.""" 
 93          ret = self.copy() 
 94          for elem in other.elems: 
 95              ret.discard(elem) 
 96          return ret 
 97   
 98 -    def __and__(self, other): 
 99          """Intersection of two sets.""" 
100          ret = Set() 
101          for elem in self.elems: 
102              if elem in other.elems: 
103                  ret.elems.append(elem) 
104          return ret 
105   
106 -    def __add__(self, other): 
107          """Symmetric difference of two sets.""" 
108          ret = Set() 
109          temp = other.copy() 
110          for elem in self.elems: 
111              if elem in temp.elems: 
112                  temp.elems.remove(elem) 
113              else: 
114                  ret.elems.append(elem) 
115          #Add remaining elements. 
116          for elem in temp.elems: 
117                  ret.elems.append(elem) 
118          return ret 
119   
120 -    def __mul__(self, other): 
121          """Cartesian product of two sets.""" 
122          ret = Set() 
123          for elemself in self.elems: 
124              x = map(lambda other, s=elemself: (s, other), other.elems) 
125              ret.elems.extend(x) 
126          return ret 
127   
128      #Some of the binary comparisons. 
129 -    def __lt__(self, other): 
130          """Returns 1 if the lhs set is contained but not equal to the rhs set.""" 
131          if len(self.elems) < len(other.elems): 
132              temp = other.copy() 
133              for elem in self.elems: 
134                  if elem in temp.elems: 
135                      temp.remove(elem) 
136                  else: 
137                      return 0 
138              return len(temp.elems) == 0 
139          else: 
140              return 0 
141   
142 -    def __le__(self, other): 
143          """Returns 1 if the lhs set is contained in the rhs set.""" 
144          if len(self.elems) <= len(other.elems): 
145              ret = 1 
146              for elem in self.elems: 
147                  if elem not in other.elems: 
148                      ret = 0 
149                      break 
150              return ret 
151          else: 
152              return 0 
153   
154 -    def __eq__(self, other): 
155          """Returns 1 if the sets are equal.""" 
156          if len(self.elems) != len(other.elems): 
157              return 0 
158          else: 
159              return len(self - other) == 0 
160