Path: utzoo!attcan!uunet!mcvax!cernvax!hjm
From: hjm@cernvax.UUCP (Hubert Matthews)
Newsgroups: comp.lang.forth
Subject: Re: Extensible or Preprocessor
Message-ID: <837@cernvax.UUCP>
Date: 26 Sep 88 17:00:44 GMT
References: <1593@crete.cs.glasgow.ac.uk> <810002@hpmtlx.HP.COM> <1650@crete.cs.glasgow.ac.uk>
Reply-To: hjm@cernvax.UUCP (Hubert Matthews)
Organization: CERN European Laboratory for Particle Physics, CH-1211 Geneva, Switzerland
Lines: 16


One problem with pre-processors is error handling.  Consider a PP that 
translates Ratfor into FORTRAN IV.  Whilst the program is running, a division
by zero occurs and an error is reported.  The line number returned is the 
number of the line that caused this exception, but in the FORTRAN program and
not the Ratfor program.  The user then has to examine the PP output in order
to determine the correspondance between his view (the Ratfor) and the PP's
view of his code.  In an extensible language, the error line number refers
directly to the user's code and not to an intermediate representation.  Do
you prefer an error message that says "div by zero in line 364" or "div by
zero at PC=00247AFC"?

	Hubert Matthews
-- 

	Hubert Matthews