Scope rule pecularities

[Greg Ewing]

Antoon Pardon wrote:
> IMO having operators that should work in place for object that
> are immutable, sound contradictory. Having the following code:

But restricting += etc. to work only on mutables would
mean you wouldn't be able to do things like

   x = 42
   x += 1

which is a very handy thing to be able to do. The current
semantics are a pragmatic compromise which seems to work
fairly well in most situations.

I suggested once that the assignment could perhaps be
skipped if the __iadd__ method returned the original
object. That would allow a_tuple[i] += something to work
in the case where the object is in-place modifiable.

-- 
Greg Ewing, Computer Science Dept,
University of Canterbury,	
Christchurch, New Zealand
http://www.cosc.canterbury.ac.nz/~greg