OverloadedRecordFields

Mateusz Kowalczyk fuuzetsu at fuuzetsu.co.uk
Tue Feb 25 17:52:15 UTC 2014


On 25/02/14 16:18, Simon Peyton Jones wrote:
> Adam
> 
> I'm very happy to hear that... good stuff.
> 
> I'm under water with ICFP submissions (deadline Sat).  Moreover I think it is clearly too later to put this into 7.8; RC1 is out and I expect RC2 any day.
> 
> So I suggest we plan to merge after 7.8 is out.  
> 
> Are the wiki pages up to date? 
> Records/OverloadedRecordFields
> Records/OverloadedRecordFields/Implementation
> Records/OverloadedRecordFields/Plan
> 
> The first does not point to the latter two; "Plan" may mean "Design"... I feel some rationalisation may make sense
> 
> Simon
> 	
> | -----Original Message-----
> | From: Adam Gundry [mailto:adam at well-typed.com]
> | Sent: 24 February 2014 08:37
> | To: Simon Peyton Jones
> | Subject: Re: OverloadedRecordFields
> | 
> | Hi Simon,
> | 
> | My OverloadedRecordFields branches[1,2,3] are up to date with HEAD as of
> | last Saturday. Validate on linux x86_64 reports only one failure, the
> | haddock.Cabal perf test, which might well be due to my Haddock changes,
> | and I will investigate. I'm not sure how to run the Haddock test suite?

Hi Adam,

I'm seeing that perf failure even without any of your changes. Perhaps
you could try validating without your changes to confirm that the perf
failure happens anyway?

There are two Haddock test-suites of interest: tests ran by GHC to make
sure that appropriate files parse (I updated these just yesterday so
please make sure you're up to date) and Haddock's own test-suite to make
sure that the output we produce is correct. To run Haddock's own tests,
you can use ‘cabal test’. You'll need QuickCheck and hspec for this.
Alternatively, to only run the tests ensuring our XHtml output is as
expected, you can run ‘cabal test html-test’. This skips the comment
parser tests (which shouldn't be relevant to you) but also doesn't force
you to install the test dependencies I mentioned.

I haven't checked your branch yet but I ask that you add appropriate
test cases in html-test. See the README in the directory for help. You
might want to check the accept.lhs file to help you doing this.

Lastly, note that we have been pushed something into Haddock every day
since Saturday so make sure you're up to date. I'll also be pushing
something today I think.

Thanks


> | 
> | I am keen to get the code reviewed and into HEAD as soon as is
> | convenient, but I'm aware these are substantial changes, and don't want
> | to rush things. In particular, I would understand if you'd rather hold
> | them back until after the 7.8 final release.
> | 
> | How would you like to proceed?
> | 
> | Adam
> | 
> | [1] https://github.com/adamgundry/ghc
> | [2] https://github.com/adamgundry/packages-base
> | [3] https://github.com/adamgundry/haddock
> | 
> | 
> | On 17/01/14 10:55, Simon Peyton Jones wrote:
> | > Yes that sounds ok, thanks.  I'd prefer to have a write-up of what
> | goes wrong with the 2-parameter story, so that we don't forget.
> | >
> | > Simon
> | >
> | > | -----Original Message-----
> | > | From: Adam Gundry [mailto:adam at well-typed.com]
> | > | Sent: 17 January 2014 10:15
> | > | To: Simon Peyton Jones
> | > | Subject: OverloadedRecordFields
> | > |
> | > | Hi Simon,
> | > |
> | > | I'm conscious that things have gone off the boil a little wrt
> | > | OverloadedRecordFields, partially as a consequence of the delayed
> | > | 7.8 release but also my lack of time for other projects since
> | > | starting work for Well-Typed. With that in mind, I'd like to propose
> | > | a plan to get back on track:
> | > |
> | > | 1. Revert to the three-parameter story, where we have
> | > |
> | > |     t ~ FldTy r f => Has r f t
> | > |
> | > | rather than
> | > |
> | > |     Has r f.
> | > |
> | > | The two-parameter version generates significantly worse error
> | > | messages, and there are some other unresolved problems, so I'm not
> | > | sure it is worth the minor simplification.
> | > |
> | > | 2. Roll back some of the refactoring that I've struggled to get
> | > | right (in particular, trying to make the generated FldTy/UpdTy
> | > | axioms implicitTyThings). We can always revisit this in the future
> | though.
> | > |
> | > | 3. Merge HEAD into my branch: I suspect this will be a bit painful
> | > | by now, but presumably with 7.8 imminent there won't be many major
> | > | changes coming for a while?
> | > |
> | > | 4. Review the proposed changes with you and fix any show-stopping
> | > | problems.
> | > |
> | > | 5. Merge into HEAD after 7.8 is released.
> | > |
> | > | Does this sound plausible? I'm happy to Skype if you like.
> | > |
> | > | Cheers,
> | > |
> | > | Adam
> | > |
> | > | P.S. I'm not sure if Andrew Kennedy has mentioned it to you, but
> | > | Neil Ghani has got me some funding to work with them both on units
> | > | of measure for Haskell. We are still sorting out the details, but I
> | > | hope it might be possible to work on some kind of plugin mechanism
> | > | for GHC's constraint solver, along the lines that Iavor has been
> | > | investigating, if that would be of interest?
> | > |
> | > | --
> | > | Adam Gundry, Haskell Consultant
> | > | Well-Typed LLP, http://www.well-typed.com/
> | >
> | 
> | 
> | --
> | Adam Gundry, Haskell Consultant
> | Well-Typed LLP, http://www.well-typed.com/
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-- 
Mateusz K.


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