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

29 Aug 2017

      Hello,

I think that we should accept this proposal.

My reasoning is as follows:
   * in traditional Haskell (e.g., 98, 2010) fixities are associated with
specific declarations, thus the same name always has the same fixity, no
matter in which module it is used.
   * I think that this is not a bug, but a feature:  fixities would be
basically unusable if they kept changiing, or somehow all libraries had to
agree on using a specific fixity ahead of time---even when they use the
same name for completely different purposes (let alone type vs. value).
   * I find the current design for `TypeOprators` to be confusing, as a
single fixity declaration, sets the fixties of two completely unrelated
names---one in the value namespace and one in the type namespace: assuming
that these two have anything to with each other seems to be a mistake.
   * the propsal suggests a rather natural way to resolve this.

-Iavor

On Tue, Aug 29, 2017 at 3:30 AM Manuel M T Chakravarty 
wrote:
...
IMHO, it is a bug that you can provide different fixities in different
modules and we should fix that bug.
Manuel
Richard Eisenberg :
Unsurprisingly, I'm in favor of this proposal and do not wish to reject.
To me, the wart on the language is that we can use the same string for a
term-level name and a potentially unrelated type-level name. Of course,
this has served many people well, but it does create a certain awkwardness
in places (and confusion for beginners!). As long as we have the
possibility of one string representing two potentially unrelated names, it
seems to be a weakness in expressiveness not to be able to assign different
fixities to the names. (And indeed we *can* assign different fixities, as
long as we do so in different modules.)
On the other hand, I am sensitive about all those other raw fish that need
frying...
Richard
On Aug 28, 2017, at 5:05 AM, Simon Peyton Jones 
wrote:
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-31905489...
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-32529477...
I added another comment
https://github.com/ghc-proposals/ghc-proposals/pull/65#issuecomment-32530108...
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@haskell.org] On Behalf Of Joachim Breitner
|  Sent: 27 August 2017 19:16
|  To: ghc-steering-committee@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:
|
https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%
https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2FRyanGlScott%2Fghc-proposals%2Fblob%2Ftype-infix%2F0000-type-infix.rst&data=02%7C01%7Csimonpj%40microsoft.com%7Cf83d705bf55c4f02639b08d4ed77cb5e%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636394546146778107&sdata=xa8HXiRK3uYOjGun7UUL3sKDVFvBVTFnXewe15pBGds%3D&reserved=0
|  2FRyanGlScott%2Fghc-proposals%2Fblob%2Ftype-infix%2F0000-type-
https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2FRyanGlScott%2Fghc-proposals%2Fblob%2Ftype-infix%2F0000-type-infix.rst&data=02%7C01%7Csimonpj%40microsoft.com%7Cf83d705bf55c4f02639b08d4ed77cb5e%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636394546146778107&sdata=xa8HXiRK3uYOjGun7UUL3sKDVFvBVTFnXewe15pBGds%3D&reserved=0
|
infix.rst&data=02%7C01%7Csimonpj%40microsoft.com%7Cf83d705bf55c4f02639b08d4e
https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2FRyanGlScott%2Fghc-proposals%2Fblob%2Ftype-infix%2F0000-type-infix.rst&data=02%7C01%7Csimonpj%40microsoft.com%7Cf83d705bf55c4f02639b08d4ed77cb5e%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636394546146778107&sdata=xa8HXiRK3uYOjGun7UUL3sKDVFvBVTFnXewe15pBGds%3D&reserved=0
|
d77cb5e%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636394546146778107&sdat
https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2FRyanGlScott%2Fghc-proposals%2Fblob%2Ftype-infix%2F0000-type-infix.rst&data=02%7C01%7Csimonpj%40microsoft.com%7Cf83d705bf55c4f02639b08d4ed77cb5e%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636394546146778107&sdata=xa8HXiRK3uYOjGun7UUL3sKDVFvBVTFnXewe15pBGds%3D&reserved=0
|  a=xa8HXiRK3uYOjGun7UUL3sKDVFvBVTFnXewe15pBGds%3D&reserved=0
https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2FRyanGlScott%2Fghc-proposals%2Fblob%2Ftype-infix%2F0000-type-infix.rst&data=02%7C01%7Csimonpj%40microsoft.com%7Cf83d705bf55c4f02639b08d4ed77cb5e%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636394546146778107&sdata=xa8HXiRK3uYOjGun7UUL3sKDVFvBVTFnXewe15pBGds%3D&reserved=0
|
https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%
https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fghc-proposals%2Fghc-proposals%2Fpull%2F65&data=02%7C01%7Csimonpj%40microsoft.com%7Cf83d705bf55c4f02639b08d4ed77cb5e%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636394546146778107&sdata=f5g17%2FpJdVe4vuwOAhrphyvXJakPFMS3yYZsi0sNG00%3D&reserved=0
|  2Fghc-proposals%2Fghc-
https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fghc-proposals%2Fghc-proposals%2Fpull%2F65&data=02%7C01%7Csimonpj%40microsoft.com%7Cf83d705bf55c4f02639b08d4ed77cb5e%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636394546146778107&sdata=f5g17%2FpJdVe4vuwOAhrphyvXJakPFMS3yYZsi0sNG00%3D&reserved=0
|
proposals%2Fpull%2F65&data=02%7C01%7Csimonpj%40microsoft.com%7Cf83d705bf55c4
https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fghc-proposals%2Fghc-proposals%2Fpull%2F65&data=02%7C01%7Csimonpj%40microsoft.com%7Cf83d705bf55c4f02639b08d4ed77cb5e%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636394546146778107&sdata=f5g17%2FpJdVe4vuwOAhrphyvXJakPFMS3yYZsi0sNG00%3D&reserved=0
|
f02639b08d4ed77cb5e%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C63639454614
https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fghc-proposals%2Fghc-proposals%2Fpull%2F65&data=02%7C01%7Csimonpj%40microsoft.com%7Cf83d705bf55c4f02639b08d4ed77cb5e%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636394546146778107&sdata=f5g17%2FpJdVe4vuwOAhrphyvXJakPFMS3yYZsi0sNG00%3D&reserved=0
|
6778107&sdata=f5g17%2FpJdVe4vuwOAhrphyvXJakPFMS3yYZsi0sNG00%3D&reserved=0
https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fghc-proposals%2Fghc-proposals%2Fpull%2F65&data=02%7C01%7Csimonpj%40microsoft.com%7Cf83d705bf55c4f02639b08d4ed77cb5e%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636394546146778107&sdata=f5g17%2FpJdVe4vuwOAhrphyvXJakPFMS3yYZsi0sNG00%3D&reserved=0
|
|  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@joachim-breitner.de
|
|
https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.joachim
https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.joachim-breitner.de%2F&data=02%7C01%7Csimonpj%40microsoft.com%7Cf83d705bf55c4f02639b08d4ed77cb5e%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636394546146778107&sdata=PLDAZw6uCBkzRl7cjF00IomTmEAuqDKd7NNjbPWkpeE%3D&reserved=0
|  -
https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.joachim-breitner.de%2F&data=02%7C01%7Csimonpj%40microsoft.com%7Cf83d705bf55c4f02639b08d4ed77cb5e%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636394546146778107&sdata=PLDAZw6uCBkzRl7cjF00IomTmEAuqDKd7NNjbPWkpeE%3D&reserved=0
|
breitner.de%2F&data=02%7C01%7Csimonpj%40microsoft.com%7Cf83d705bf55c4f02639b
https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.joachim-breitner.de%2F&data=02%7C01%7Csimonpj%40microsoft.com%7Cf83d705bf55c4f02639b08d4ed77cb5e%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636394546146778107&sdata=PLDAZw6uCBkzRl7cjF00IomTmEAuqDKd7NNjbPWkpeE%3D&reserved=0
|
08d4ed77cb5e%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636394546146778107
https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.joachim-breitner.de%2F&data=02%7C01%7Csimonpj%40microsoft.com%7Cf83d705bf55c4f02639b08d4ed77cb5e%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636394546146778107&sdata=PLDAZw6uCBkzRl7cjF00IomTmEAuqDKd7NNjbPWkpeE%3D&reserved=0
|  &sdata=PLDAZw6uCBkzRl7cjF00IomTmEAuqDKd7NNjbPWkpeE%3D&reserved=0
https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.joachim-breitner.de%2F&data=02%7C01%7Csimonpj%40microsoft.com%7Cf83d705bf55c4f02639b08d4ed77cb5e%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636394546146778107&sdata=PLDAZw6uCBkzRl7cjF00IomTmEAuqDKd7NNjbPWkpeE%3D&reserved=0
_______________________________________________
ghc-steering-committee mailing list
ghc-steering-committee@haskell.org
https://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-steering-committee
_______________________________________________
ghc-steering-committee mailing list
ghc-steering-committee@haskell.org
https://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-steering-committee
_______________________________________________
ghc-steering-committee mailing list
ghc-steering-committee@haskell.org
https://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-steering-committee

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

Iavor Diatchki