Is there no switch function in Python

[Alex Martelli]

Leif K-Brooks <eurleif at ecritters.biz> wrote:

> Bengt Richter wrote:
> > But IWT if we had named local code suites, we could exec them safely via
a mapping. E.g.,
> > 
> >     def foo(var): # following is not legal code ;-)
> >         v1: print 'var is one'
> >         v2: # any suite should be ok, not just one-liners
> >             print 'var',
> >             print 'is two'
> >         switch = {1:v1, 2:v2}    
> >         exec switch.get(var, '')
> 
> I'm probably missing something, but what's wrong with:
> 
> def foo(var):
>       def v1(): print 'var is one'
>       def v2():
>               print 'var',
>               print 'is two'
>       switch = {1:v1, 2:v2}
>       switch.get(var, lambda:None)()

Nothing wrong.  However, if v1 and v2 needed to rebind some names within
foo, they couldn't according to def's semantics -- they could only
rebind local names of their own, or global names with a global
statement, but not local names in their outer function foo.  I think the
right approach, if that feature is a must-have, might be to add the one
missing feature, not with a weird new syntax which forces one to choose
between taking arguments and rebinding outer functions' locals, but with
an optional scope indicator on variables.  Just IMHO, anyway.


Alex