[Haskell-cafe] Re: ANN: System.FilePath 0.9

[Bulat Ziganshin]

Hello Brian,

Sunday, July 23, 2006, 5:31:35 PM, you wrote:

>>> instance IString ByteString.Char8 ...
>>> instance IString String ...
>> class ListLike ce e | ce->e

>     class ISeq seq_a a | seq_a -> a where -- (*)

there is also Collection library:
darcs get --partial http://darcs.haskell.org/packages/collections/

it contains many classes, including:

-- | Class of sequential-access types.
-- In addition of the 'Collection' services, it provides deconstruction and concatenation.
class (Monoid c, Collection c a a) => Sequence c a where
    -- | The first @i@ elements of a sequence.
    take :: Int -> c -> c
    -- | Elements of a sequence after the first @i at .
    drop :: Int -> c -> c
    -- | Split a sequence at a given index.
    splitAt :: Int -> c -> (c,c)
    -- | Reverse a sequence.
    reverse :: c -> c
    -- | Analyse the left end of a sequence.
    front :: Monad m => c -> m (a,c)
    -- | Analyse the right end of a sequence.
    back :: Monad m => c -> m (c,a)
    -- | Add an element to the left end of a sequence.    
    cons :: a -> c -> c
    -- | Add an element to the right end of a sequence.
    snoc :: c -> a -> c
    -- | The 'isPrefix' function takes two seqences and returns True iff 
    -- the first is a prefix of the second.
    isPrefix :: Eq a => c -> c -> Bool


but this class is not ideal for integration with ByteString library
which implements many custom algorithms which (i suppose) use details
of ByteString implementation. so, something like

class (Sequence c a) => ListLike c a where
  split, splitBy....

would be useful. and then we should integrate your idea:

>      class IChar c where
>      class (IChar c, ISeq s c) => IString s where

-- 
Best regards,
 Bulat                            mailto:Bulat.Ziganshin at gmail.com