On Tue, 4 Sep 2007, Peter Verswyvelen wrote:
> Henning Thielemann wrote:
> > Why not just
> > FancySequence.fromList [1,2,3,4]
> > or
> > FancySequence.fromList $ 1:2:3:4:[]
> > ?
> Yes of course, but the same could be said for numbers, e.g when you need
> an Int, you have to type (Int.fromNumber 1), (Float.fromNumber 1),
> (Double.fromNumber 1), etc... I don't like that because it makes writing
> numeric type independent generic code impossibe, so luckily the Haskell
> compiler automatically inserts fromInteger or fromRational calls to lift
> a generic number into a specific representation. But it does not provide
> the same for lists, e.g. there is no fromList function which is a member
> of some List typeclass that the compiler automatically uses just like it
> does for numbers. I think this is a bit of a discrepancy.
If you are happy with writing "do {1;2;3;4}" you are certainly also happy
with "cv [1,2,3,4]", where cv means 'convert' and is a method of a class
for converting between lists and another sequence type.
class ListCompatible lc where
cv :: [a] -> lc a
rt :: lc a -> [a] {- restore :-) -}
Better don't adapt the names, but the idea would work, wouldn't it?
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