Two Proposals

[Wolfgang Jeltsch]

Am Freitag, den 30.09.2011, 19:28 +0200 schrieb George Giorgidze:
> Basically the idea is to treat list literals like:
> 
> [1,2,3]
> 
> as
> 
> fromList [1,2,3]
> 
> where
> 
> class IsList l where
>   type Item l
>   fromList :: [Item l] -> l

Could we *please* not have classes whose names start with “Is”? We don’t
have classes IsNum, IsEq, or IsOrd, so why should we have IsList and
IsString?

I know that the identifier String is already taken, but please don’t tie
an identifier like IsString or IsList to a language feature, so that
it’ll be difficult to change it later. Let’s search for a better
solution.

> In the following I give useful instances of the IsList class.
> 
> […]
> 
> instance (Ord a) => IsList (Set a) where
>   type Item (Set a) = a
>   fromList = Set.fromList

As a set is definitely not a list, the class should better be named
differently anyway, shouldn’t it?

Don’t know if these issues have already been pointed out, since I didn’t
read through the complete thread. Sorry, if they have already.

Best wishes,
Wolfgang