Add docstrings.

Lib/collections.py

@@ -36,6 +36,11 @@ class OrderedDict(dict, MutableMapping):
     # Those hard references disappear when a key is deleted from an OrderedDict.
 
     def __init__(self, *args, **kwds):
+        '''Initialize an ordered dictionary.  Signature is the same as for
+        regular dictionaries, but keyword arguments are not recommended
+        because their insertion order is arbitrary.
+
+        '''
         if len(args) > 1:
             raise TypeError('expected at most 1 arguments, got %d' % len(args))
         try:
@@ -47,12 +52,14 @@ class OrderedDict(dict, MutableMapping):
         self.update(*args, **kwds)
 
     def clear(self):
+        'od.clear() -> None.  Remove all items from od.'
         root = self.__root
         root.prev = root.next = root
         self.__map.clear()
         dict.clear(self)
 
     def __setitem__(self, key, value):
+        'od.__setitem__(i, y) <==> od[i]=y'
         # Setting a new item creates a new link which goes at the end of the linked
         # list, and the inherited dictionary is updated with the new key/value pair.
         if key not in self:
@@ -64,6 +71,7 @@ class OrderedDict(dict, MutableMapping):
         dict.__setitem__(self, key, value)
 
     def __delitem__(self, key):
+        'od.__delitem__(y) <==> del od[y]'
         # Deleting an existing item uses self.__map to find the link which is
         # then removed by updating the links in the predecessor and successor nodes.
         dict.__delitem__(self, key)
@@ -72,6 +80,7 @@ class OrderedDict(dict, MutableMapping):
         link.next.prev = link.prev
 
     def __iter__(self):
+        'od.__iter__() <==> iter(od)'
         # Traverse the linked list in order.
         root = self.__root
         curr = root.next
@@ -80,6 +89,7 @@ class OrderedDict(dict, MutableMapping):
             curr = curr.next
 
     def __reversed__(self):
+        'od.__reversed__() <==> reversed(od)'
         # Traverse the linked list in reverse order.
         root = self.__root
         curr = root.prev
@@ -88,6 +98,7 @@ class OrderedDict(dict, MutableMapping):
             curr = curr.prev
 
     def __reduce__(self):
+        'Return state information for pickling'
         items = [[k, self[k]] for k in self]
         tmp = self.__map, self.__root
         del self.__map, self.__root
@@ -109,6 +120,10 @@ class OrderedDict(dict, MutableMapping):
     __ne__ = MutableMapping.__ne__
 
     def popitem(self, last=True):
+        '''od.popitem() -> (k, v), return and remove a (key, value) pair.
+        Pairs are returned in LIFO order if last is true or FIFO order if false.
+
+        '''
         if not self:
             raise KeyError('dictionary is empty')
         key = next(reversed(self)) if last else next(iter(self))
@@ -116,21 +131,31 @@ class OrderedDict(dict, MutableMapping):
         return key, value
 
     def __repr__(self):
+        'od.__repr__() <==> repr(od)'
         if not self:
             return '%s()' % (self.__class__.__name__,)
         return '%s(%r)' % (self.__class__.__name__, self.items())
 
     def copy(self):
+        'od.copy() -> a shallow copy of od'
         return self.__class__(self)
 
     @classmethod
     def fromkeys(cls, iterable, value=None):
+        '''OD.fromkeys(S[, v]) -> New ordered dictionary with keys from S
+        and values equal to v (which defaults to None).
+
+        '''
         d = cls()
         for key in iterable:
             d[key] = value
         return d
 
     def __eq__(self, other):
+        '''od.__eq__(y) <==> od==y.  Comparison to another OD is order-sensitive
+        while comparison to a regular mapping is order-insensitive.
+
+        '''
         if isinstance(other, OrderedDict):
             return len(self)==len(other) and \
                    all(_imap(_eq, self.iteritems(), other.iteritems()))