[Python-ideas] Python Users Aren't Perfect

[Antoine Pitrou]

On Thu, 15 Dec 2011 15:42:42 -0500
Ned Batchelder <ned at nedbatchelder.com>
wrote:
> On 12/15/2011 3:24 PM, Georg Brandl wrote:
> > On 12/13/2011 03:44 AM, Stephen J. Turnbull wrote:
> >> Greg Ewing writes:
> >>   >  Masklinn wrote:
> >>   >
> >>   >  >  FWIW, Haskell does not have a literal singleton (the standard defines
> >>   >  >  "unit" `()` and 2-tuple through 15-tuple)
> >>   >
> >>   >  That's because, due to its static typing, there is no
> >>   >  reason you would ever need to use a 1-tuple rather than
> >>   >  a bare value. We're not that lucky in Python, though.
> >>
> >> I think you have misstated your point?  That's not due to static
> >> typing, that's because you may *always* identify 1-factor products
> >> with the only factor, and Haskell made a deliberate decision to
> >> consistently represent the isomorphism class by the factor rather than
> >> the product.
> > Well, I would say the reason is that the type "tuple of any length" does
> > not exist in Haskell.  So there's no way you will have to pass a 1-tuple
> > to a function that operates on tuples only.
> >
> > But of course, if we all used tuples as tuples only, we wouldn't have to do
> > that either.  It's only because we use tuples as sequences every so often.
> This is another place where Python is inconsistent.  We're told, "lists 
> are for homogenous sequences of varying length, like a C array; tuples 
> are for heterogenous aggregations of known length, like a C struct."   
> Then we define a function foo(*args), and Python gives us a tuple!  :-(

How is it inconsistent? Function signatures generally have a fixed (or
mostly fixed) number of heterogenous arguments.

Regards

Antoine.