[ghc-steering-committee] Proposal: Type Fixity (#65), Recommendation: Reject

[Simon Peyton Jones]

I don't have a strong opinion either way. The strongly reason in favour is encapsulated in Richard's comment

https://github.com/ghc-proposals/ghc-proposals/pull/65#issuecomment-319054892

which points out that the two T's are entirely unrelated.



I had not fully realised this, but in fact it is /already/ possible to have different fixities for a single lexeme T; a concrete example is here

https://github.com/ghc-proposals/ghc-proposals/pull/65#issuecomment-325294776



I added another comment

https://github.com/ghc-proposals/ghc-proposals/pull/65#issuecomment-325301080

that tries to separate the AST issue from the source-code issue.  I do think we should make the internal change; but I’m unconvinced it’s worth the faff to solve the source-level issue.



Simon





|  -----Original Message-----

|  From: ghc-steering-committee [mailto:ghc-steering-committee-

|  bounces at haskell.org] On Behalf Of Joachim Breitner

|  Sent: 27 August 2017 19:16

|  To: ghc-steering-committee at haskell.org

|  Subject: [ghc-steering-committee] Proposal: Type Fixity (#65),

|  Recommendation: Reject

|

|  Dear Committee,

|

|  Ryan Scott’s proposal to allow fixity declaration to explicitly target

|  values or types has been brought before us:

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|

|  I (the secretary) nominates myself as the shepherd, so I can right away

|  continue giving a recommendation.

|

|  I propose to reject this proposal. The main reasons are:

|   * it is not clear if there is a real use case for this. Has anyone

|     ever complained about the status quo?

|     The proposal does not motivate the need for a change well enough.

|     (There is a related bug in TH, but that bug can probably simply be

|     fixed.)

|   * The status quo can be sold as a feature, rather than a short-coming.

|     Namely that an operator has a fixed fixity, no matter what namespace

|     it lives in.

|     This matches morally what other languages do: In Gallina, fixity

|     is assigned to names independent of their definition, AFAIK.

|   * There is a non-trivial implementation and education overhead, a

|     weight that is not pulled by the gains.

|

|  If we’d design Haskell from scratch, my verdict might possibly be different

|  (but maybe we wouldn’t even allow types and values to share names then…)

|

|

|  Please contradict me or indicate consensus by staying silent.

|

|

|  Greetings,

|  Joachim

|

|  --

|  Joachim “nomeata” Breitner

|    mail at joachim-breitner.de<mailto:mail at joachim-breitner.de>

|

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