[Python-bugs-list] [ python-Bugs-471828 ] x<<n loses bits in 2.2.a4

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Bugs item #471828, was opened at 2001-10-16 12:25
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http://sourceforge.net/tracker/?func=detail&atid=105470&aid=471828&group_id=5470

Category: Python Interpreter Core
>Group: Not a Bug
>Status: Closed
>Resolution: Invalid
Priority: 5
Submitted By: Nobody/Anonymous (nobody)
>Assigned to: Guido van Rossum (gvanrossum)
Summary: x<<n loses bits in 2.2.a4

Initial Comment:
This change from pep-0237 has not made it to Python
2.2.a4.
The pep says:

	Currently, x<<n can lose bits for short ints.  This
will be
	changed to return a long int containing all the
shifted-out
	bits, if returning a short int would lose bits.

Python still behaves as before:

Python 2.2a4 (#1, Oct 17 2001, 19:05:19) 
[GCC egcs-2.91.66 19990314/Linux (egcs-1.1.2 release)]
on linux2
Type "help", "copyright", "credits" or "license" for
more information.
>>> 1<<30
1073741824
>>> 1<<31
-2147483648
>>> 1<<32
0
>>> 

The change would of course cause incompatibilities with
existing programs
relying on the old behaviour so I am not sure I want it
very much
myself. But just mentioning it, I suppose either the
pep or Python
needs updating.


Sverker Nilsson



----------------------------------------------------------------------

>Comment By: Guido van Rossum (gvanrossum)
Date: 2001-10-16 12:59

Message:
Logged In: YES 
user_id=6380

SectionTransition label A explains this: this is one of the
semantic aspects that will be addressed after 2.2.

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