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

27 Feb 2015

      On 27/02/15 09:58, Oliver Charles wrote:
...
So you would argue that these should desugar to the same thing?
I guess I'm talking more generally here. On the one hand, I find this
practical and convenient. On the other hand, it (almost by design)
breaks our usual intuition of how the space works.

E.g. in most other cases  id x  is the same as  x, but inside idiom
brackets they mean x and pure x, respectively.

I don't have a specific suggestion, just a concern.
...
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" mailto:roma@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
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