[Haskell-cafe] Policy for taking over a package on Hackage

Mario Blažević mblazevic at stilo.com
Fri May 27 15:36:31 CEST 2011

On 11-05-25 08:52 AM, Johan Tibell wrote:
> On Wed, May 25, 2011 at 2:01 PM, Ivan Lazar Miljenovic
> <ivan.miljenovic at gmail.com>  wrote:
>> With my wl-pprint-text package, Jason Dagit suggested to me on
>> #haskell that it would make sense to make such a pretty-printer be
>> class-based so that the same API could be used for String, ByteString,
>> Text, etc.
> I'm a bit skeptical of using type classes to abstract over Unicode
> string types and byte sequence types. The only API shared by the two
> kind of types is that of a sequence. Things like dot , spaces, etc.
> don't make much sense on binary data. You must assume that the
> ByteString contains text in some encoding to make sense of such
> concepts.

    You don't necessarily need spaces and dot to abstract over
bytestrings and Unicode string types. They both implement IsString and
Monoid classes, as well as operations null, length, isPrefixOf, take,
and drop.

    That's sufficient to implement a generic parser that works on any
input type supporting these operations (see [1] for example), though
there is some performance cost. I don't see why a pretty-printer
should be any more difficult.

[1] http://hackage.haskell.org/package/incremental-parser

More information about the Haskell-Cafe mailing list