Re: types with value parameter (another example of application)

1999-03-04 Thread Juergen Pfitzenmaier

Hi,

I spend a lot of time developing a generic C++ library to handle
symbolic manipulation of (nearly) arbitarily polynomials. There are a
lot of cases when (the so called) type system of C++ is no of help and
I needed to implement my own kind of dynamic types with checking at
runtime. For example let K be a field and let A and B be two
Polynomials. At runtime we set up variables x and y , then construct
two different polynomial Rings K[x] and K[y] and then state that A is
an element of K[x] and B is an element of K[y].  Now A and B may share
the same structure in the data structures that represents them and
both are univariate polynomials but the expression A = A+B is
senseless and invalid. This is a case that no static type checker can
detect, so don't expect to much from it (and don't expect anything
usefull from the stupid implementation of templates in C++). This and
several others made me exploring some functional languages to
reimplement a enhanced version of my library. Up to now it appears to
me that I still have to code some of the type-checking by hand,
because anything else seems to require a complicated theorem prover at
compile time.  

ciao Juergen


Herbert Graeber wrote:

> I have taken a look on these papers at
>
> http://www.cl.cam.ac.uk/~ajk13/
> http://ftp.cs.chalmers.se/users/pub/rittri/dimpolyrec.ps.Z
>
> But I discovered, that there is one important difference to the C++ example
> I posted. The type system is extended to allow inference of deimensions. The
> C++ version does not need extensions specific to dimensions. The language
> features already present (templates) allow this without extending the
> language.
>
> I think there is no way to add compile time dimension checking (and many
> other similar things) in Haskell. May be Haskell 2 should contain an
> extended type system, that allows that. I am not firm with depended types.
> Perhaps that's the way do such things.
>
> Cheers,
> Herbert






cfp SAS'99 - Venice

1999-03-04 Thread Agostino Cortesi

*

 Last Call For Papers

 International Static Analysis Symposium (SAS'99)

   Venezia, Italy,
22--24 September 1999

 Submission Deadline: 15 march, 1999


   for info, please look at: http://www.dsi.unive.it/~sas99/

*



As usual, I deeply apologize for multiple copies
___
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Re: GHC in Japanese Fifth Generation Project!

1999-03-04 Thread Frank A. Christoph

>I was amused to disover recently (thanks to Zhou-san, at POPL) that
>the name GHC (well, really FGHC or `flat' GHC) has already been used,
>by the Japanese Fifth Generation Project.
>
>FGHC stands for Flat Guided Horn Clause, and it's a language that was
>used by the project for knowledge representation:

That would explain something mildly suprising that I saw yesterday on Gerard Huet's 
home page. It includes a list of "major software projects" that he has participated 
in, and near the end is an entry entitled "GHC Interpreter"...!

--FC






Re: Market Penetration of FP and Haskell

1999-03-04 Thread Philip Wadler

"S. Alexander Jacobson" <[EMAIL PROTECTED]> writes:

> So, if they are making sure that all platforms have a scheme interpreter,
> why not make the spec language agnostic.  i.e. allow the user to use any
> language that can be compiled/translated into scheme (by code written in
> scheme?).

Your assumption is incorrect.  There is no Scheme interpreter in XSL.

I should have been clearer in my earlier comment: XSL is a special
purpose language with a highly specialised structure (as Alexander
notes, it is a little like production rules).  It is not as general as
either Haskell or Scheme.  DSSSL, unlike XSL, was embedded in Scheme
and provided both the specialised structure and general-purpose Scheme
computation.  I'd be very happy if XSL was as nice as Scheme!

> So the user would be able to say:
> http://www.haskell.org/haskell2scheme>
> 

There is an extension mechanism in XSL to allow part of the transformation
to be done in another language, roughly similar to the above.

-- P






OOSDS99 Call for papers

1999-03-04 Thread Natalia Ioustinova



This message contains public information, only, and the receiver
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Our apologies if you received duplicates of this message due to the
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You can also visit the OOSDS'99 web site at
http://www.tec.informatik.uni-rostock.de/IuK/congr/oosds99/


   CALL FOR PAPERS

   OOSDS'99
   
Workshop on Object-Oriented Specification Techniques
for Distributed Systems and Behaviours

Paris, France, September 27, 1999
http://www.tec.informatik.uni-rostock.de/IuK/congr/oosds99/



SCOPE OF WORKSHOP:
=
The workshop is focused on specification languages for distributed 
systems which are extensions of object-oriented languages or have an 
object-oriented kind of base structure. The aim is to bring together
researchers interested in incorporating object-oriented concepts 
and  formal methods for specification of distributed systems and
behaviours. 

TOPICS (NOT EXCLUSIVE LIST):

Object-oriented approaches to specification of distributed systems 
and behaviours.

Semantic models for concurrency and object-orientation (e.g. based on the 
lambda-calculus, process algebra, pi-calculus, linear logic).

Characteristic examples of object-oriented specification from real 
application domains (e.g. distributed algorithms, workflow specification, 
communication protocols).

Logic reasoning on distributed systems and behaviours.

SUBMISSION:
===
The deadline for submission is September 2, 1999. 
Submission is in electronic form only.
Submission may be of two forms:
Extended abstracts: up to 3 pages.
Papers and reports: up to 6 pages.
In both cases a separate page with the following information: 
title, author(s), corresponding author,
contact information and a 12-15 lines summary 
should be included.
The papers and/or abstracts should be sent by e-mail to 
[EMAIL PROTECTED]
Selection for presentation will be carried out by the organizers.
Emphasis is put on the potential of the submission to stimulate 
discussions in the above-mentioned scope.
Notification of acceptance is expected for September 14, 1999.

PUBLICATION:

The accepted submissions will be published electronically,
i.e. they will remain available from the workshop web page.
Furthermore, selected papers will be invited for post
workshop publication. 

RELATED EVENTS:
==
This workshop is organized as a satellite workshop of PPDP'99, 
The 1999 International Conference on  Principles and Practice 
of Declarative Programming, Paris, France, September 29-October 1, 1999. 
http://www.dmi.ens.fr/~fages/PPDP99/

ORGANIZATION COMMITTEE:
===
Clemens H. Cap  (Rostock University, Germany) 
Natalia Ioustinova  (Rostock University, Germany) 
Javier Oliver  (Technical University of Valencia, Spain) 
Nobuko Yoshida  (University of Sussex, UK)

ADDITIONAL INFORMATION:
===
WEB: http://www.tec.informatik.uni-rostock.de/IuK/congr/oosds99/
MAIL: [EMAIL PROTECTED]


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