[swift-evolution] Changing the curried static methods

[Brandon Williams]

I think this highlights some of the confusion around the current curried
convention. Void methods are curried as A -> () -> (), which means you
would use it like:

UIView.removeFromSuperview # => UIView -> () -> ()
UIView.removeFromSuperview(view) # => () -> ()
UIView.removeFromSuperview(view)() #> ()

I find this confusing because removeFromSuperview reads as an action, yet
UIView.removeFromSuperview(view) does not perform the action but rather is
an action itself that requires a further invocation ().

With arguments flipped we would have:

UIView.removeFromSuperview # => () -> UIView -> ()
UIView.removeFromSuperview() # => UIView -> ()
UIView.removeFromSuperview()(view) #> ()

It now reads to me that UIView.removeFromSuperview() is the action that
will do the removing, and UIView.removeFromSuperview()(view) is applying
the action to a view.

I don’t advocate using removeFromSuperview in this manner, but if one were
to I believe the latter convention is easier to reason about without having
to look up types in a playground (as I had to do a few times to write this
:P)


On Sun, Mar 13, 2016 at 1:50 PM Erica Sadun via swift-evolution <
swift-evolution at swift.org> wrote:

>
> > On Mar 13, 2016, at 11:30 AM, Stephen Celis <stephen.celis at gmail.com>
> wrote:
> >
> >> On Mar 13, 2016, at 1:18 PM, Erica Sadun <erica at ericasadun.com> wrote:
> >>
> >> Since removeFromSuperview doesn't take a UIView argument, it sounds
> like what you're looking for is
> >> something that acts like "apply", to apply a
> lambda/closure/selector/whatever to each member of a collection.
> >>
> >> view.subviews.apply(UIView.removeFromSuperview)
> >>
> >> -- E
> >
> > This is what `forEach` currently does with the existing curried static
> syntax, right?
> >
> > I was more interested in the implications of an example brought up in
> the OP:
> >
> >    frames.map(CGRect.insetBy(-10, -10))
> >
> > - Stephen
>
> forEach currently does f(x).
> apply would do x.f()
>
> -- E
>
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