[ghc-steering-committee] Amend or patterns (#522) to use p1 ; p2 (#609)

[Adam Gundry]

No objections from me. I tend not to pay too much attention to such 
syntactic niceties, but as the authors have gone to the trouble of 
surveying the community and implementing the proposal I see no reason 
not to accept their suggested syntax.

I did notice that the PR drops Ömer's name from the authors list for 
#522, I'm not sure if that was intentional?

Adam


On 08/09/2023 18:47, Vladislav Zavialov wrote:
> In favor
> 
> On Fri, Sep 8, 2023 at 6:36 PM Simon Peyton Jones 
> <simon.peytonjones at gmail.com <mailto:simon.peytonjones at gmail.com>> wrote:
> 
>     I don't have a strong opinion here.   The authors have done a pretty
>     diligent job of exploring syntactic alternatives, and seeking
>     feedback from the community.  I'm quite content to accept this
>     proposal.  (We have already accepted the base or-pattern proposal,
>     so that's not our subject for debate.)
> 
>     Simon
> 
>     On Fri, 8 Sept 2023 at 03:57, Chris Dornan <chris at chrisdornan.com
>     <mailto:chris at chrisdornan.com>> wrote:
> 
>         Proposal: Amend or patterns (#522) to use p1 ; p2 (#609)
>         Author: Sebastian Graf, David Knothe
>         Rendered proposal:
>         https://github.com/ghc-proposals/ghc-proposals/blob/eb4b67c29282520b2c5c6a49c3047dbecb15dde1/proposals/0522-or-patterns.rst <https://github.com/ghc-proposals/ghc-proposals/blob/eb4b67c29282520b2c5c6a49c3047dbecb15dde1/proposals/0522-or-patterns.rst>
>         Discussion:
>         https://github.com/ghc-proposals/ghc-proposals/pull/609
>         <https://github.com/ghc-proposals/ghc-proposals/pull/609>
>         Recommendation: Acceptance
> 
>         ## Summary
> 
>         This proposal refines the syntax of an already accpted proposal
>         (#522) for writing or patterns.
> 
>         The syntax of the old proposal,
> 
>         ```haskell
>         stringOfT :: T -> Maybe String
>         stringOfT (T1 s) = Just s
>         stringOfT (one of T2{}, T3{}) = Nothing
>         ```
> 
>         is replaced with
> 
>         ```haskell
>         stringOfT :: T -> Maybe String
>         stringOfT (T1 s) = Just s
>         stringOfT (T2{}; T3{}) = Nothing
>         ```
> 
>         or indeed
> 
>         ```haskell
>         stringOfT :: T -> Maybe String
>         stringOfT x = case x of
>         T1 s -> Just s
>         T2{}
>         T3{} -> Nothing
>         ```
> 
>         (Beacuse the '(' ... ')' are optional here, we can remove them
>         and naturally exploit layout.)
> 
>         The authors have conducted polls to see what folks preferred,
>         landing on this proposal. The
>         adjustments to the Haskell grammar are really quite minimal
>         requiring one extra production.
> 
>         ## Recommendation
> 
>         The proposal is nondiruptive and as a whole addresses an
>         important practical topic. I recommend
>         that we accept it
> 


-- 
Adam Gundry, Haskell Consultant
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