Re: what about moving the record system to an addendum?
On Mon, 2009-07-06 at 18:28 -0700, John Meacham wrote: Well, without a replacement, it seems odd to remove it. Also, Haskell currently doesn't _have_ a record syntax (I think it was always a misnomer to call it that) it has 'labeled fields'. None of the proposed record syntaxes fit the same niche as labeled fields so I don't see them going away even if a record syntax is added to haskell in the future. The people proposing this can correct me if I'm wrong but my understanding of their motivation is not to remove record syntax or immediately to replace it, but to make it easier to experiment with replacements by making the existing labelled fields syntax a modular part of the language that can be turned on or off (like the FFI). I'm not sure that I agree that it's the best approach but it is one idea to try and break the current impasse. It seems currently we cannot experiment with new record systems because they inevitably clash with the current labelled fields and thus nothing changes. Duncan ___ Haskell-prime mailing list Haskell-prime@haskell.org http://www.haskell.org/mailman/listinfo/haskell-prime
Re: what about moving the record system to an addendum?
On 7 Jul 2009, at 02:28, John Meacham wrote: Haskell currently doesn't _have_ a record syntax (I think it was always a misnomer to call it that) it has 'labeled fields'. ... and a reworking of the standard to not refer to the current system as a 'record syntax' but rather a 'labeled fields' syntax. I strongly agree with the latter. In fact, I was under the impression that the Report already avoided the term record syntax completely, but checking just now showed 6 distinct occurrences. Regards, Malcolm ___ Haskell-prime mailing list Haskell-prime@haskell.org http://www.haskell.org/mailman/listinfo/haskell-prime
Re[2]: what about moving the record system to an addendum?
Hello Duncan, Tuesday, July 7, 2009, 2:15:42 AM, you wrote: For one thing the spec currently says that pragmas cannot change the semantics of the program. That would have to read apart from the LANGUAGE pragma. sometime ago i've proposed to make a language statement a part of haskell. i don't insist on this but at least keep this possibility in mind - making it a pragma is a poor man solution -- Best regards, Bulatmailto:bulat.zigans...@gmail.com ___ Haskell-prime mailing list Haskell-prime@haskell.org http://www.haskell.org/mailman/listinfo/haskell-prime
Re: what about moving the record system to an addendum?
Malcolm Wallace wrote: On 7 Jul 2009, at 02:28, John Meacham wrote: Haskell currently doesn't _have_ a record syntax (I think it was always a misnomer to call it that) it has 'labeled fields'. ... and a reworking of the standard to not refer to the current system as a 'record syntax' but rather a 'labeled fields' syntax. I strongly agree with the latter. In fact, I was under the impression that the Report already avoided the term record syntax completely, but checking just now showed 6 distinct occurrences. ah hah. Existing extension names: NamedFieldPuns (was erroneously RecordPuns in GHC for a release) RecordWildCards, DisambiguateRecordFields this extension could be named NamedFields. (then giving the lie to the above new names which maybe ought to be more like FieldWildCards and DisambiguateNamedFields(DisambiguateFieldNames?)) Also there is ExtensibleRecords which I guess refers to Hugs' TRex? -Isaac ___ Haskell-prime mailing list Haskell-prime@haskell.org http://www.haskell.org/mailman/listinfo/haskell-prime
Re: what about moving the record system to an addendum?
Hello, I do not think that we should remove the current record/named fields syntax, at least for the moment. I use it a lot, and I do not want to add extra pragmas or extensions to my cabal file. In fact, one of the purposes of Haskell', the way I understand it, is exactly to just choose a stable set of extensions and give a name to them (so decrease, not increase the number of pragmas). I think that a new reocrd/label system is way beyond the scope of Haskell'. If people want to experiment with new record systems they may already do so, by defining a new extension. A case in point is the Trex record system, which is implemented in Hugs. -Iavor 2009/7/7 Ravi Nanavati r...@bluespec.com: 2009/7/7 Duncan Coutts duncan.cou...@worc.ox.ac.uk: On Mon, 2009-07-06 at 18:28 -0700, John Meacham wrote: Well, without a replacement, it seems odd to remove it. Also, Haskell currently doesn't _have_ a record syntax (I think it was always a misnomer to call it that) it has 'labeled fields'. None of the proposed record syntaxes fit the same niche as labeled fields so I don't see them going away even if a record syntax is added to haskell in the future. The people proposing this can correct me if I'm wrong but my understanding of their motivation is not to remove record syntax or immediately to replace it, but to make it easier to experiment with replacements by making the existing labelled fields syntax a modular part of the language that can be turned on or off (like the FFI). I'm not sure that I agree that it's the best approach but it is one idea to try and break the current impasse. It seems currently we cannot experiment with new record systems because they inevitably clash with the current labelled fields and thus nothing changes. I think it is a powerful approach to try and break the current impasse for the following reasons: 1. Once implemented, Hackage and Cabal will soon give us accurate data on what publicly available Haskell code does and does not depend on NamedFields/TraditionalRecordSyntax/WhateverWeEndUpCallingIt 2. Once deprecated, people will be encouraged to not depend on the traditional record syntax where the cost of avoiding it is small (I'm thinking of situations like the mtl-accessors / run functions where the traditional syntax is saving something like one function definition). 3. Champions of alternative record syntaxes will know what on Hackage they can use out-of-the-box and what things they'd want to consider re-writing as examples of how their approach is superior. Does anyone have a concrete dea of what it would take to carve out the existing syntax as an addendum? Thanks, - Ravi ___ Haskell-prime mailing list Haskell-prime@haskell.org http://www.haskell.org/mailman/listinfo/haskell-prime ___ Haskell-prime mailing list Haskell-prime@haskell.org http://www.haskell.org/mailman/listinfo/haskell-prime
what about moving the record system to an addendum?
According to http://hackage.haskell.org/trac/haskell-prime/wiki/Status,
ticket #99 was rejected, but the tickets own page,
http://hackage.haskell.org/trac/haskell-prime/ticket/99, says
probably yes. Which is it?
I was about to propose this myself, but decided to check the trac just
in case it had already been proposed, Haskell being so popular with
smart people and all, and was at first rather disappointed and ready
to write an angry rant to the list, then rather confused when I
noticed the ticket's page said almost the exact opposite of the Status
page.
In particular, I want records to be considered an extension to
Haskell', to be implemented only by compilers that care, and even then
only allowed with a LANGUAGE pragma like this:
{-# LANGUAGE TraditionalRecordSyntax #-}
For pre-Haskell' compilers, we would want something like:
{-# LANGUAGE NoTraditionalRecordSyntax #-}
which would mean extending the LANGUAGE pragma to support turning
extensions off by adding/removing a No from the front of it.
Hmm, is it really the case that nobody has proposed LANGUAGE pragmas for
Haskell'? I don't see them listed on the Status page.
I guess the work involved here is basically:
(a) Go through Haskell 98, find all the parts that talk specifically
about record syntax, and write up the list of such places.
(b) Implement this in GHC:
http://hackage.haskell.org/trac/ghc/ticket/3356
(c) Add support for negating extension names by adding/removing No in
front of extension names to Cabal:
http://hackage.haskell.org/trac/hackage/ticket/567
(d) Add {-# LANGUAGE #-} to Haskell'
What do you folks think?
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Re: what about moving the record system to an addendum?
Well, without a replacement, it seems odd to remove it. Also, Haskell currently doesn't _have_ a record syntax (I think it was always a misnomer to call it that) it has 'labeled fields'. None of the proposed record syntaxes fit the same niche as labeled fields so I don't see them going away even if a record syntax is added to haskell in the future. I would like to see the simple modifications to the record syntax listed on this page though http://hackage.haskell.org/trac/haskell-prime/wiki/ExistingRecords and a reworking of the standard to not refer to the current system as a 'record syntax' but rather a 'labeled fields' syntax. John -- John Meacham - ⑆repetae.net⑆john⑈ - http://notanumber.net/ ___ Haskell-prime mailing list Haskell-prime@haskell.org http://www.haskell.org/mailman/listinfo/haskell-prime
