[nem-en] out / ref

[Ivan A Eryshov]

> On Behalf Of Michal Moskal
> 
> You're completely right. The problem is that we already have foo (3,
> _). And I'm not quite sure we want to change it. Maybe we should,
> however partial application seems to be much more frequent than out _
> (maybe I havn't used API with "out" parameters much though).

I think the best way is to change '_' in partials, but a bunch of codes
already use '_' in partials, so this change can be not practical.

> OTOH now, when we have that "x => f (3, x)" notation it might not be
> that useful.
> 
> Any suggestions what to use instead of _ in for partial application?

What do you think about '?':
	? - something
	_ - nothing
:-)