Proposal: Add split and splitWith (trac #2048)

[Duncan Coutts]

On Thu, 2008-01-17 at 17:36 +0100, Christian Maeder wrote:
> Ian Lynagh wrote:
> > One or the other should be changed so that these agree:
> > 
> > *Main> split 'a' ""
> > [""]
> > *Main> Data.ByteString.Char8.split 'a' (Data.ByteString.Char8.pack "")
> > Loading package array-0.1.0.0 ... linking ... done.
> > Loading package bytestring-0.9.0.1 ... linking ... done.
> > []
> > 
> > although I couldn't say which is "right" OTTOMH...
> 
> I've convinced myself (see my previous mails) that Twan's version is
> right and Data.ByteString.Char8.split should be changed (and all its
> usages need to be checked)!
> 
> The documentation in both modules should contain the example!
>   split c [] == [[]]
> 
> I don't think that the oddity of Data.ByteString.Char8.split on empty
> input helps to establish the treatment of a missing final newline for
> the lines function.

If everyone thinks this is the right behaviour we can certainly change
Data.ByteString to follow. It is supposed to follow the Data.List api.

Duncan