[Haskell-cafe] Idiom Brackets for GHC (first full proposal)

[Oliver Charles]

So you would argue that these should desugar to the same thing? I'm on the
fence - on the one hand its nice to be able to leave a few 'pure's out, but
on the other those parenthesis have no syntactic meaning before, so it's
questionable why they suddenly do inside idiom brackets.

I can live with needing a few more 'pure's though.

- Ollie
On 26 Feb 2015 23:28, "Roman Cheplyaka" <roma at ro-che.info> wrote:

> I'm starting to like this. Except the weird difference between spaces on
> different levels that you point out, i.e.
>
> [| const True False |]
>
> vs
>
> [| (const True) False |]
>
>
>
>
> On 26/02/15 23:04, Oliver Charles wrote:
> > Hi all,
> >
> > A few days ago I made a post here to gauge interest in adding idiom
> > brackets to GHC. Response was a bit more mixed than I was hoping, but no
> > one seemed to drastically against the idea, so I've moved forward with a
> > more detailed proposal.
> >
> > You can find the full proposal here:
> >
> >     https://ocharles.org.uk/IdiomBrackets.html
> >
> > A particular difference in my proposal from existing solutions comes
> > from my desire to lift almost *all* expressions - with the original
> > syntax - into idiom brackets. This means normal function application and
> > tuples, but also case expressions, let bindings, record construction,
> > record update, infix notation, and so on.
> >
> > At first I was skeptical about this, but I am finding uses for this more
> > and more. I really like how it lets me use the interesting data (that
> > is, whatever is "under" the applicative functor) where it's most
> > relevant - rather than having to build a function and thread that value
> > back through. Examples of this can be seen in my proposal.
> >
> > To prove its use, I've been working with this Template Haskell
> > expression:
> >
> >     https://ocharles.org.uk/IdiomExp.hs
> >
> > It *almost* does exactly what I want, the only problem is I can't get
> > Template Haskell to give me a difference between
> >
> >     $(i [| const True False |])
> >
> > and
> >
> >     $(i [| (const True) False |])
> >
> > which I was planning to be significant.
> >
> > The proposal has mostly grown into my own personal notebook, so I'm
> > happy to clarify anything that is vague/contradictory/confusing.
> >
> > Look forward to hearing your thoughts!
> >
> > -- Ollie
> > _______________________________________________
> > Haskell-Cafe mailing list
> > Haskell-Cafe at haskell.org
> > http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe
> >
>
>
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