[Template-haskell] instance declarations

[François-Régis Sinot]

Forget this: the kind error is due to another mistake.

Thanks for your help.
fr.

le mar 15-04-2003 à 03:19, François-Régis Sinot a écrit :
> Hi
> 
> Could anyone recall me the syntax for instance declarations ?
> (eg what form should have the 2nd argument to Instance ?)
> 
> My best guess was something like:
> 
> genReg' :: Q [Dec]
> genReg' = do dec1<-fun "out" [clause [pvar "x"] (normal [|foo|]) []]
> 	     ctx1<-ctxt []
> 	     clss<-tapp (tcon (TconName "Regular")) 
> 	                (tcon (TconName "Tree"))
> 	     return [Instance ctx1 clss [dec1]] 
> 
> intended to produce something like:
> 
> instance Regular Tree where
>    out x = ...
> 
> But it gives a kind error on Tree:
> 
> Kind error: `Tree' is not applied to enough type arguments
> When checking kinds in `Regular Tree'
> In the instance declaration for `Regular Tree'
> 
> More generally, is there some kind of comprehensive up-to-date
> documentation for this kind of questions ?
> 
> Thanks,
> fr.
> 
> 
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