Haskell Implemetors Meeting

[Simon Peyton-Jones]

Title:

Gentle Haskellers,

A few weeks ago (following POPL) there was an informal meeting of some
people involved in implementing Haskell. In this message I summarise
some of the things we discussed, because I think many of them will be of general interest.

People with actions are in CAPITALS.  Key:
        MANUEL          Manuel Chakravarty
        SIGBJORN        Sigbjorn Finne
        JOHN            John Launchbury
        ANDREW          Andrew Tolmach
        MALCOLM         Malcolm Wallace
        HENRIK          Henrik Nilsson
        OLAF            Olaf Chitil    
        SIMON M         Simon Marlow
        SIMON PJ        Simon Peyton Jones

Simon

=================================================================

Haskell Report
~~~~~~~~~~~~~~
SIMON PJ still hasn't put out the revised H98 report.  Jump to it!


Foreign Function Interface
~~~~~~~~~~~~~~~~~~~~~~~~~~
Going splendidly, but needs writing up as a proper "Blessed Addendum"
to the H98 report, so that compilers can say "I implement H98 plus
FFI".

MANUEL agreed to be Editor for the Addendum, and drive the process.

H/Direct and Green Card: SIGBJORN is going to work at Galois, and
will continue to look after and develop these tools. Indeed, he's
already started hacking on them again.  Hooray!


Haskell implementation
~~~~~~~~~~~~~~~~~~~~~~
Hugs:   OGI in maintenance mode.  There's a danger that Hugs will
        gradually die, which none of us want.  One idea: advertise
        openly for a home for Hugs.  JOHN will take this
        suggestion to OGI.

nhc:    Being actively maintained and developed at York

GHC:    4.08.2 release imminent
        Simon M and Julian gave a demo of the upcoming
        interactive GHCi demo; release expected in a
        month or two.

        We agreed that it would be a Jolly Good Thing if GHC could
        be persuaded to produce GHC-independent Core output,
        ready to feed into some other compiler.  For example,
        Karl-Filip might be able to use it. 
        ANDREW will write a specification, and implement it.

        MANUEL is writing an inside-the-monster roadmap.  He'll
        put it in fptools/ghc somewhere, so others can add to it.


Haskell Libraries
~~~~~~~~~~~~~~~~~
MALCOLM produced a proposal for a (tiny) language extension that
would give us a hierarchical name space for modules (a la Java). 
We loved it.  He will refine it into a concrete document to
circulate more widely.

We agreed (again) about the importance of libraries.  The "hslibs"
libraries are a good start.  They are *not* part of GHC, even though
they happen to live in the same CVS repository.  We agreed they
should stay there, but should have a less GHC-specific build/test
system.

We appointed a troika of Library Supremos, namely

        MALCOLM, SIMON M, ANDY

Specific tasks:
        - get closure on Malcolm's module-naming proposal
        - agree hslibs hierarchy
        - define documentation standards
        - act as gatekeepers for contributions

SIMON M will create a mailing list for library discussions.


Graphical user interfaces
~~~~~~~~~~~~~~~~~~~~~~~~~
We got a useful taxomomy:

--------------------------------------------------------
High-level      Fran/Tk         Fudgets    (Haggis)


--------------------------------------------------------
Medium-level    Clean Object I/O        School of
abstractions    [GUI]                   Expression (SOE)
                                        [Graphics]

--------------------------------------------------------
Low-level
veneers         HOpenGL     Gtk  Haskell/Tk   Win32   X
on existing     [Graphics]
libraries
--------------------------------------------------------

Low-level veneers are going well -- but they are
low level.  High-level abstractions are pretty experimental.

We need a medium-level GUI library.  Peter Achten's port
of the Clean Object I/O system looks like a great candidate.
Well documented, lots of experience in use, about the right
level.

SIMON PJ to seek agreement from Nijmegen, and then advertise
for someone to complete the port.

OLAF will articulate the above taxonomy on haskell.org


HaskellDoc
~~~~~~~~~~
We all loved Armin Groesslinger's HDoc tool.  HENRIK will get in
touch with him to invite him to collaborate on a standard tool
we can all use.  (Of course, it's up to him.)

Two specific ideas:
   Take a Haskell source file into some XML-stuff,
   which can then be rendered in various ways. 
   (Rather than going straight to HTML.)

   Use standard pragma syntax: {-# DOC ... #-}

[Post meeting note: mailing list at
         http://www.haskell.org/mailman/listinfo/haskelldoc
]

Debugging
~~~~~~~~~
Hat (York): Expect a release in the Spring.
            In the summer they hope for a first cut at at
            an implementation-portable version

Hood:       ANDY plans to release his graphical version


IDE
~~~
Galois are interested in working on Haskell-in-Visual-Studio.


Haskell.org
~~~~~~~~~~~
Idea: have a "job adverts" page on haskell.org, for tasks
that need doing.  For example:

        * Integrate Haskell with "Source Navigator"
        * Offer libraries
        * Complete Clean I/O port
        * Contribute nofib programs
        * Contribute validation programs

Action OLAF.