[Python-checkins] r54987 - sandbox/trunk/abc/abc.py

[guido.van.rossum]

Author: guido.van.rossum
Date: Thu Apr 26 20:26:08 2007
New Revision: 54987

Modified:
   sandbox/trunk/abc/abc.py
Log:
Make it match the current PEP 3119 a little more (e.g. SizedMapping->Mapping).
Experiment with implementing set composition operations a little differently.


Modified: sandbox/trunk/abc/abc.py
==============================================================================
--- sandbox/trunk/abc/abc.py	(original)
+++ sandbox/trunk/abc/abc.py	Thu Apr 26 20:26:08 2007
@@ -15,6 +15,7 @@
 __author__ = "Guido van Rossum <guido at python.org>"
 
 import sys
+import itertools
 
 
 ### ABC SUPPORT FRAMEWORK ###
@@ -252,25 +253,33 @@
 
     # XXX Alternatively, we might make these abstract.
 
+    @staticmethod
+    def fromiterable(it):
+        return frozenset(it)
+
     def __and__(self, other):
-        new = set(self)
-        new.intersection_update(other)
-        return frozenset(new)
+        if not isinstance(other, Iterable):
+            return NotImplemented
+        return self.fromiterable(value for value in other if value in self)
 
     def __or__(self, other):
-        new = set(self)
-        new.update(other)
-        return frozenset(new)
+        return self.fromiterable(itertools.chain(self, other))
 
     def __xor__(self, other):
-        new = set(self)
-        new.symmetric_difference_update(other)
-        return frozenset(new)
+        if not isinstance(other, Set):
+            if not isinstance(other, Iterable):
+                return NotImplemented
+            other = self.fromiterable(other)
+        return self.fromiterable(itertool.chain(
+            (value for value in self if value not in other),
+            (other for value in other if value not in self)))
 
     def __sub__(self, other):
-        new = set(self)
-        new.difference_update(other)
-        return frozenset(new)
+        if not isinstance(other, Set):
+            if not isinstance(other, Iterable):
+                return NotImplemented
+            other = self.fromiterable(other)
+        return self.fromiterable(value for value in self if value not in other)
 
 
 # XXX Should this derive from Set instead of from ComposableSet?
@@ -448,19 +457,19 @@
             yield self._mapping[key]
 
 
-class SizedMapping(IterableMapping, Sized):
+class Mapping(IterableMapping, Sized):
 
     def keys(self):
-        return SizedKeysView(self)
+        return KeysView(self)
 
     def items(self):
-        return SizedItemsView(self)
+        return ItemsView(self)
 
     def values(self):
-        return SizedValuesView(self)
+        return ValuesView(self)
 
     def __eq__(self, other):
-        if not isinstance(other, SizedMapping):
+        if not isinstance(other, Mapping):
             return NotImplemented
         if len(other) != len(self):
             return False
@@ -476,21 +485,21 @@
         return True
 
 
-class _SizedMappingView(_MappingView, Sized):
+class _MappingView(_MappingView, Sized):
 
     def __len__(self):
         return len(self._mapping)
 
 
-class SizedKeysView(_SizedMappingView, KeysView, Set):
+class KeysView(_MappingView, KeysView, Set):
     pass
 
 
-class SizedItemsView(_SizedMappingView, ItemsView, Set):
+class ItemsView(_MappingView, ItemsView, Set):
     pass
 
 
-class SizedValuesView(_SizedMappingView, ValuesView):
+class ValuesView(_MappingView, ValuesView):
 
     def __eq__(self, other):
         if not (isinstance(other, Sized) and isinstance(other, Iterable)):
@@ -723,10 +732,10 @@
         return len(self.adaptee)
 
 
-class AdaptToMapping(SizedMapping):
+class AdaptToMapping(Mapping):
 
     def __new__(cls, adaptee):
-        self = SizedMapping.__new__(cls)
+        self = Mapping.__new__(cls)
         self.adaptee = adaptee
         return self