[Python-checkins] CVS: python/dist/src/Include abstract.h,2.32,2.33

[Tim Peters]

Update of /cvsroot/python/python/dist/src/Include
In directory usw-pr-cvs1:/tmp/cvs-serv17966/python/dist/src/Include

Modified Files:
	abstract.h 
Log Message:
Generalize tuple() to work nicely with iterators.
NEEDS DOC CHANGES.
This one surprised me!  While I expected tuple() to be a no-brainer, turns
out it's actually dripping with consequences:
1. It will *allow* the popular PySequence_Fast() to work with any iterable
   object (code for that not yet checked in, but should be trivial).
2. It caused two std tests to fail.  This because some places used
   PyTuple_Sequence() (the C spelling of tuple()) as an indirect way to test
   whether something *is* a sequence.  But tuple() code only looked for the
   existence of sq->item to determine that, and e.g. an instance passed
   that test whether or not it supported the other operations tuple()
   needed (e.g., __len__).  So some things the tests *expected* to fail
   with an AttributeError now fail with a TypeError instead.  This looks
   like an improvement to me; e.g., test_coercion used to produce 559
   TypeErrors and 2 AttributeErrors, and now they're all TypeErrors.  The
   error details are more informative too, because the places calling this
   were *looking* for TypeErrors in order to replace the generic tuple()
   "not a sequence" msg with their own more specific text, and
   AttributeErrors snuck by that.


Index: abstract.h
===================================================================
RCS file: /cvsroot/python/python/dist/src/Include/abstract.h,v
retrieving revision 2.32
retrieving revision 2.33
diff -C2 -r2.32 -r2.33
*** abstract.h	2001/05/05 00:14:56	2.32
--- abstract.h	2001/05/05 03:56:37	2.33
***************
*** 912,916 ****
           members of this list.
  
!          Returns NULL on failure.  If the object is not a sequence,
           raises a TypeError exception with m as the message text.
         */
--- 912,916 ----
           members of this list.
  
!          Returns NULL on failure.  If the object does not support iteration,
           raises a TypeError exception with m as the message text.
         */