[Haskell] Proposal: Allow "\=" for field update in record update syntax

Lemmih lemmih at gmail.com
Fri Mar 4 09:35:58 EST 2005


On Fri, 4 Mar 2005 15:26:52 +0100, Benjamin Franksen
<benjamin.franksen at bessy.de> wrote:
> On Sunday 20 February 2005 14:19, Keean Schupke wrote:
> > TH has supported multi-parameter classes for a while... new in 6.4 is
> > support for fundeps.
> 
> Yes, but unfortunately TH cannot create instances for them which is usually
> the boilerplate you want to avoid. From Language.Haskell.TH:
> 
> data Dec =
>         ...
>         ClassD Cxt Name [Name] [FunDep] [Dec]
>         InstanceD Cxt Type [Dec]
>         ...
> 
> Only one 'Type' can be given for an instance.

And there _should_ only be one type. Checkout 'appT'.
Some real documentation for TH would clear misconceptions such as this.

-- 
Friendly,
  Lemmih


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