Proposal: Export String from Data.String (and two related proposals)

[Bas van Dijk]

On Wed, Oct 20, 2010 at 10:19 PM, Bas van Dijk <v.dijk.bas at gmail.com> wrote:
> Hello,
>
> I would like to make three proposals, in order of importance IMHO:
>
> 1. Export String from Data.String. Most modules in base and on
> Hackage of the form: Data.<type> also export <type>. I think it's
> surprising and confusing that Data.String doesn't conform to this
> pattern.
>
> 2. Unexport String from Data.Char. I feel less strongly about this
> one, but in general I think it is good that a symbol is exported from as
> few modules as possible.
>
> 3. Export the String operations: lines, words, unlines and
> unwords from Data.String. I feel even less strongly about this one.
> However these are operations on Strings so it makes sense to export them
> from Data.String. As a counter argument you could say these operations
> either receive or produce a _list_ of Strings so they only belong in
> Data.List.
>
> If we accept 3 then in the spirit of  "export a symbol from as few modules
> as possible", you may expect a fourth proposal: Unexport the String
> operations: lines, words, unlines and unwords from Data.List.
> However I think this will break lots of programs. I have no problem also
> discussing this one though.
>
> Discussion deadline:
>
> 3 weeks from now: Wednesday 10 November.
>
> Ticket with patches:
>
> http://hackage.haskell.org/trac/ghc/ticket/4422
>
> Regards,
>
> Bas
>

The deadline of this proposal has passed. However, due to the recent
activity on the libraries list, I would like to extend the deadline by
a week: Thursday 18 November.

Regarding proposal 2: Unexport String from Data.Char, I made a quick
analysis of the latest versions of all packages on Hackage which
import String from Data.Char:

$ find . -type f -print0 | xargs -0 -e grep -l -e "import.*Data\.Char.*String"
./usb-id-database-0.4.0.4/System/USB/IDDB/Base.hs
./usb-id-database-0.4.0.4/System/USB/IDDB/UsbDotOrg.hs
./usb-id-database-0.4.0.4/System/USB/IDDB/LinuxUsbIdRepo.hs
./usb-id-database-0.4.0.4/System/USB/IDDB/Misc.hs
./ftdi-0.2.0.1/test.hs
./usb-safe-0.11/System/USB/Safe.hs
./safer-file-handles-0.9/System/IO/SaferFileHandles.hs
./ls-usb-0.1.0.7/PrettyDevList.hs
./dstring-0.4/Data/DString.hs
./regional-pointers-0.5/Foreign/C/String/Region.hs
./usb-0.6.0.4/System/USB/Internal.hs
./concurrent-extra-0.6/Control/Concurrent/ReadWriteLock.hs
./concurrent-extra-0.6/TestUtils.hs
./explicit-iomodes-0.6/System/IO/ExplicitIOModes.hs
./hamusic-0.1.2.1/src/Music/Analysis/Abstract2Lilypond.lhs
./hamusic-0.1.2.1/src/Music/Analysis/Base.lhs
./hamusic-0.1.2.1/src/Music/Analysis/Interface.lhs
./musicxml-0.1.2/src/Text/XML/MusicXML/Direction.lhs
./musicxml-0.1.2/src/Text/XML/MusicXML/Common.lhs
./musicxml-0.1.2/src/Text/XML/MusicXML/Note.lhs
./roman-numerals-0.4.0.1/Text/Numeral/Roman.hs

All these packages are maintained by either me or my brother, except
for hamusic and musicxml which are maintained by Samuel Silva.

Regards,

Bas