From: Jurgen Vinju
To: Multiple recipients of list PEM <>
Date: Wed, 14 Nov 2001 14:42:28 +0100
Subject: PEM | 15.11.01 | M280

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   Some news concerning tomorrow's talk:
   An updated version of the LDTA'01 paper on the new action semantics is
   currently available at http://www.brics.dk/~pdm/tmp/DohMosses.pdf

   ASF+SDF  sources  of  the  examples  in  this  paper can be downloaded
   tomorrow from http://www.brics.dk/~pdm/tmp/MetaEnv/

   Dear colleagues,

   Next  Thursday we will receive an international guest. Peter D. Mosses
   will  bring  us  up-to-date with the latest developments around Action
   Semantics. Please read the following abstract:

   This announcement can be found with links at
   <http://www.cwi.nl/htbin/jurgenv/pem/pem.cgi?1005822000>

                        Action Semantics and ASF+SDF

   Date:    15.11.01
   Time:    11:00
   Venue:   M280
   Speaker: Peter D. Mosses
   Title:   Action Semantics and ASF+SDF

   Action   Semantics   is  a  hybrid  of  denotational  and  operational
   semantics,  developed  mainly  during the late 1980's and early 1990's
   and  revised  and simplified in 2000. The semantic functions in Action
   Semantics map program syntax (compositionally) to actions expressed in
   Action   Notation,   the   semantics   of   which  is  itself  defined
   operationally.   The   main   advantage   of   Action  Semantics  over
   conventional denotational semantics is that the actions specifying the
   semantics of programming constructs can be given once and for all.

   As  reported  at  LDTA'01,  the  modular  structure of descriptions in
   Action  Semantics has recently been reconsidered. The main idea is for
   the  description  of  the  syntax and (one possible) semantics of each
   construct  to  be  specified  as a separate module, so that a complete
   language can be specified simply by importing the desired modules.

   The  ASD  Tools  by A. van Deursen implemented the original version of
   Action  Semantics  in  ASF+SDF. However, the ASD Tools rely heavily on
   the  original  modular  structure  of Action Semantics, and it appears
   that  it  would be difficult to update the implementation to cope with
   the  new  modular  structure. At Aarhus we are therefore experimenting
   with writing Action Semantics directly in ASF+SDF.

   The talk gives an overview of the revised version of Action Semantics,
   and  illustrates how Action Semantics is written in ASF+SDF, using the
   new  modular  structure.  The  audience is assumed to be familiar with
   ASF+SDF.

   Have a nice day.
     _________________________________________________________________

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