From: Jurgen Vinju
To:
Date: Fri, 5 Nov 2004 13:10:04 +0100
Subject: PEM: Hedzer Westra | CobolX |  7.02.02

 
From: pem (PEM moderator)
To: pem-noreply
Subject: PEM meeting |  7.02.02 | C001 
Precedence: bulk
X-url: http://www.cwi.nl/~pem
Mime-Version: 1.0
Content-Type: text/plain;
        charset="iso-8859-1"

   Dear colleagues,

   Next  thursday  we welcome Hedzer Westra, who will bring us up-to-date
   with his work on COBOL transformations using XT.

   This announcement can be found at <http://www.cwi.nl/~pem>

                                   CobolX

   Date:     7.02.02
   Time:    10:00
   Venue:   C001
   Speaker: Hedzer Westra
   Title:   CobolX

   Many  legacy  computer  programs  are still being used today, e.g., at
   bank  computer  systems.  Manual  maintenance  of  these  programs  is
   becoming  too  expensive.  Therefore,  it is desirable to automate all
   kinds of routine modifications.

   An  important requirement in such modifications is the preservation of
   comments  and  the original layout of the programs. Furthermore, since
   there  are  many,  more  or less closely related, computer programming
   languages,  a  system  designed  for  this  purpose should be flexible
   towards the language being used.

   Another  requirement  is  the ability to easily plug in transformation
   steps with the least technical problems possible.

   CobolX  is  an  environment  for implementing transformations on COBOL
   programs  that fulfills these requirements. It uses the Transformation
   Tools  (XT)  package,  which  provides  tools  for parsing (SDF/SGLR),
   transformation  (Stratego) and pretty printing (GPP). The Grammar Base
   (GB)  consists  of  a  large  set of grammar definitions, usable by XT
   tools.

   Since  COBOL is a complex language with many dialects, it is necessary
   to  automatically generate signatures and pretty-print tables from the
   syntax  definition,  since hand coding is not feasible. The XT package
   provides  grammar  tools  for this purpose. These tools are adapted to
   support the layout preservation requirement.

   The  Stratego standard library (SSL) is extended to provide the plugin
   facility that is needed for CobolX.

   As  case studies, two transformations are implemented using the CobolX
   system: picture scaling and GOTO elimination. Picture scaling involves
   propagating  information  about  affected  variables  and then scaling
   pictures  of  variable  declarations  and  scaling constants. The GOTO
   elimination  transformation  removes as many GO statements as possible
   from a program by using a systolic transformation algorithm.
     _________________________________________________________________

   The  programming environment meetings are a forum for the presentation
   and  discussion  of  new  ideas,  ongoing and finished work. A typical
   meeting  addresses  a subject in the area of programming environments,
   program  generation, algebraic specification, term rewriting, parsing,
   etc.  A presentation ideally takes between 45 and 90 minutes. Meetings
   taking  longer  than 45 minutes are interrupted by a coffeebreak. Most
   Thursdays,  a  meeting is held which starts at 10:00 am. in one of the
   rooms at CWI/WINS. Exceptionally, dates or times may change.

   The    program    of    the    meetings    is    available   on   WWW:
   http://www.cwi.nl/~pem
     _________________________________________________________________