Re: [ghc-steering-committee] #167: Deprecated Entities, rec: accept

Hi, I fully support this (I thought I brought it up before, but maybe not strongly enough). Should we just include this change in #167? (If politicians can add random riders to laws, so can we). Or does it need more thought? Cheers, Joachim Am Freitag, den 08.03.2019, 14:46 +0000 schrieb Simon Peyton Jones via ghc-steering-committee:

I also argue that, to be consistent, whatever keyword we agree, we should use it In the (accepted) infix/WARNING proposal In import and export lists – presumably for now in addition to ‘pattern’, though we might end up deprecating the latter. Simon

From: Vitaly Bragilevsky Sent: 08 March 2019 14:44 To: Simon Peyton Jones Cc: Simon Marlow ; ghc-steering-committee Subject: Re: [ghc-steering-committee] #167: Deprecated Entities, rec: accept

Simon PJ argues for "value" over "data" as a specifier: https://github.com/ghc-proposals/ghc-proposals/pull/167#issuecomment-4709471...

I'm fine with this choice either (and I'm satisfied with the argument that deprecating or setting fixity for value "value" is a rare case to be considered seriously). If you have another opinion, please, speak up.

Vitaly

On Fri, Mar 8, 2019 at 11:42 AM Simon Peyton Jones wrote:

...

I’ve made a post on the proposal thread asking why we don’t just follow the already-adopted proposal for WARNING and infix pragmas.

Simon

From: ghc-steering-committee On Behalf Of Simon Marlow Sent: 08 March 2019 07:57 To: Vitaly Bragilevsky Cc: ghc-steering-committee Subject: Re: [ghc-steering-committee] #167: Deprecated Entities, rec: accept

Yes, I think this is the right way to go.

Cheers Simon

On Fri, 8 Mar 2019 at 05:25, Vitaly Bragilevsky wrote:

...

Hi everyone,

I was asked to shepherd the proposal #167 (Deprecated Entities, https://github.com/nineonine/ghc-proposals/blob/depr-entities/proposals/0000...). It is proposed to extend (nonpositional) DEPRECATED pragma with the two specifiers to disambiguate deprecating named type-level and value-level things. In its current formulation, the proposal suggests to use the specifiers "type" for type-level things and "pattern" for value-level things as follows:

data Bar = Bar {-# DEPRECATED type Bar "Don't use type Bar" #-} data Baz = Baz {-# DEPRECATED pattern Baz "Don't use data constructor Baz" #-}

Using this pragma without specifiers should mean deprecating both (as is works now).

After discussing this proposal within the committee (see https://mail.haskell.org/pipermail/ghc-steering-committee/2019-February/0008...), I recommend acceptance with one change, namely using "data" instead of "pattern" for deprecating value-level things.

Reasons for choosing "data": * it's a reserved keyword (as opposed to "value", which is another option) * we are deprecating data constructors here * it just feels right (sorry!)

Reasons against "data": * it can be confusing whether we mean data type or data constructor * we use "value" and "pattern" in other places meaning basically the same thing

If the committee decides to go this way, then the wider community may think about other proposals, such as * adding positional DEPRECATED pragmas (including class instances deprecation) * fixing inconsistencies with the fixity declarations (https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0008-ty...) and updating ExplicitNamespaces in import/export lists * deprecating usage of nonpositional DEPRECATED pragma without the specifiers

Silence is understood as agreement.

Regards, Vitaly

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_______________________________________________ ghc-steering-committee mailing list ghc-steering-committee@haskell.org https://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-steering-committee -- Joachim Breitner mail@joachim-breitner.de http://www.joachim-breitner.de/