Re: [Haskell-cafe] extensible records - Vinyl - alternatives?

Hi Adam, thanks for your answer, I will re-check HList with Labelable labels. With regards to your question "named labels": good point, all records indeed have "named labels" so what was my statement? I actually thought that Vinyl does keep run-time information of the labels from a Blog about vinyl-gl, but actually I'm not so sure about it anymore, so it is more a question: do those alternatives of extensible records differentiate by the way they keep runtime information of labels? regards Peter 2014-05-03 18:54 GMT+02:00 adam vogt :

Hello Peter,

Could you show what you mean by "named labels"?

Vinyl is a fine choice, but have you looked at HList >= 0.3? The lenses/labels done with Data.HList.Labelable are prettier than the vinyl alternative in my biased opinion. Furthermore, they support changing types in the record unlike vinyl (ie. they provide a Lens not Lens').

HList is a bit slow at compile time http://code.haskell.org/~aavogt/HList-benchmark/a.html if you make records with many fields. That situation may improve soon if we take advantage of the ordering on Symbol that ghc-7.8 introduced. In other words, we will probably follow the lead of http://www.haskell.org/haskellwiki/CTRex and make Records sorted by their labels.

...

. Also consider lens' makeClassy as another solution to the records

There are quite a few other libraries <http://www.haskell.org/haskellwiki/Extensible_record#Libraries_on_hackage problem.

Regards, Adam

On Sat, May 3, 2014 at 6:16 AM, Peter Althainz wrote:

...

Dear All,

I'm searching a handsome library for handling large amounts of configuration data in a flexible manner. So to speak I want to use some kind of inheritance of data fields. I think this is where the extensible records discussion is a proper description of my use case.

I've found 2 libraries making this work, so far:

HList Vinyl

I currently prefer Vinyl due to the complex types in HList, lens compatibiliy, named labels. (I love the HList and OOHaskel papers, but for practical use, I currently prefer Vinyl).

What do you think, what is the best way nowadays to use extensible records? Is Vinyl a good choice from your point of view?

regards Peter

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