[Haskell-cafe] Trouble understanding records and existential typesy

Chris Kuklewicz haskell at list.mightyreason.com
Fri Jan 26 05:32:41 EST 2007

John Meacham wrote:
> On Wed, Jan 24, 2007 at 05:03:18PM -0800, Stefan O'Rear wrote:
>> Haskell-98 style records are widely acknowledged as sucking, and there are
>> something like half a dozen proposals all of which are widely acknowledged
>> as vastly superior.  Expect to be stuck with H98 records for the remainder
>> of time; see "bikeshed".
> actually, the problem is that we keep calling them records. Haskell 98
> records are actually labeled fields, not records, and as labeled fields
> they perform just fine.
> Not that records or named tuples or whatever you like to call them
> wouldn't be useful but they would likely be something in addition to labeled
> fields, not replacing it. (Not that the current labeled field mechanism
> couldn't be improved some.)
> personally, something based on Daan's scoped labels proposal is the
> clear leader of the bunch.
>         John

I also really liked Daan's "Extensible records with scoped labels", which is
available at http://www.cs.uu.nl/~daan/pubs.html#scopedlabels for those who
still have not read it.  The system seems very simple, but also seems to have
required moving beyond an imperative viewpoint to come up with.

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