[ghc-steering-committee] Records again

[Joachim Breitner]

Hi,


Am Dienstag, den 17.12.2019, 11:46 +0000 schrieb Simon Peyton Jones via
ghc-steering-committee:
> > I.e. I will support `f r.x = f (r.x)`, if I can still add space before the
> > .x.
> 
> That gets into a separate question, the "naked selector" question.  There we have the following viable alternatives
> 
> (1) .x is illegal
> (2) .x means (\r. r.x)
> (3) .x is a postfix operator
> 
> Certainly (3) would all you to write
> 	r .x .y        meaning r.x.y
> or
> 	f (r .x .y)    meaning f (r.x.y)
> 
> But I was trying to close the discussion of (f r.x) before opening the discussion about 1/2/3 for naked selectors.

I don't think it can be answered separately. Maybe it can be seen as a
clearly separate question if one strongly believes that `r.f` is the
roughly the same thing as `M.f`. While I understand that view, I do not
strongly believe in it, e.g. because we have `(complex expression).f`
and `r.f.g.h`, and this shows me that `e.f` is a more complex and less
atomic notion than a qualified name `M.f`.

In order to form a decision about `f r.x = f (r.x)` I also need to know
whether I can, for example, align vertically (a very Haskelly desire)
without changing meaning:

   printf "%s %s"  grandfather.first_name  grandfather.last_name
   printf "%s %s"  mom        .first_name  mom        .last_name
   printf "%s %s"  (kid!!0   ).first_name  (kid!!0)   .last_name


(I am not saying that this is universally good style, but it is also
not completely unreasonable.)

Cheers,
Joachim

-- 
Joachim Breitner
  mail at joachim-breitner.de
  http://www.joachim-breitner.de/