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Date: Tue, 14 Jan 2003 12:04:28 +0100
Subject: PEM | 16.01.03 | M280

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   Dear colleagues,

   You are invited to attend the following talk on grammar engineering by
   Steven Klusener (VU/SIG).

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

        Tolerant parsing of Cobol systems for efficiently organizing
                          transformation projects

   Date:    16.01.03
   Time:    10:00
   Venue:   M280
   Speaker: Steven Klusener
   Title:   Tolerant parsing of Cobol systems for efficiently organizing transf
ormation projects

   In  this talk I discuss the work I've been doing at VU, in cooperation
   with  Ernst-Jan  Verhoeven,  Niels Veerman, Ralf Laemmel and Jan Kort.
   First  I  recall how the Grammar Development Kit (GDK) of Jan Kort and
   Ralf  Laemmel  can be used to obtain an SDF grammar from the Cobol IBM
   VS  Reference  Manual  grammar which can be used for parsing IBM Cobol
   sources.  The  Reference  Manual  grammar  as  such is not appropriate
   because  many  aspects,  such  as  nested  statements and preprocessor
   statements,  are  not  covered by the grammar but are described in the
   text that explains the grammar.

   A  typical  transformation  project involves only a selected number of
   syntax  constructs  (sorts  and  productions  of  the grammar). I will
   discuss  an  approach in which a "subgrammar" is derived from the full
   IBM  Cobol  grammar which is sufficient for the actual transformation.
   For  example  for Cobol restructuring and GOTO elimination we need all
   structured  statements,  the GOTO statement and some other statements,
   but  we  can  still skip most of the Cobol grammar. The advantages are
   obvious;  the subgrammar is not only a subgrammar IBM Cobol, but it is
   also a subgrammar of most other dialects like Microfocus Cobol. Hence,
   the  Cobol  restructuring algorithm can be applied to Microfocus Cobol
   as well without any further fine-tuning of its grammar.

   The  motivation  of  tolerant  parsing is similar to the motivation of
   Island grammars. The difference with Island grammars is that we have a
   structured  approach to derive the subgrammar from a reference grammar
   like   IBM  Cobol.  Each  ASF-specification  has  a  "contract"  which
   specifies  the  sorts  and  productions  it  needs  from the reference
   grammar.  Hence,  an ASF-specification can be used in every subgrammar
   that covers at least this "contract"

   Have a nice day.
     _________________________________________________________________

   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
     _________________________________________________________________