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

adam vogt vogt.adam at gmail.com
Sat May 3 16:54:23 UTC 2014

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.

There are quite a few other libraries
Also consider lens' makeClassy as another solution to the records


On Sat, May 3, 2014 at 6:16 AM, Peter Althainz <althainz at gmail.com> 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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