Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!rutgers!uwvax!tank!mimsy!cvl!haven!umbc3!mbph!hybl
From: hybl@mbph.UUCP (Albert Hybl  Dept of Biophysics  SM)
Newsgroups: comp.lang.fortran
Subject: Character aliases are Satanic extensions
Keywords: Exorcist needed
Message-ID: <592@mbph.UUCP>
Date: 9 May 89 22:28:50 GMT
Organization: University of Maryland, School of Medicine, Baltimore, MD 21201
Lines: 54


        I am converting a set of programs containing a total of about
60,000 line of "standard" fortran code written for a VAX computer.  The
following is typical of several hundred diagnostics I have encountered:

      DOUBLE PRECISION   NAME,NAMA,JTYPM,ISPEC
      DATA   IDNA,IRNA,ISPEC/4HD   ,4HR   ,8H$SPECIAL /

   98. *********** DATA IDNA,IRNA,ISPEC/4HD   ,4HR   ,8H$SPECIAL / <=== 
       ***** Error number 78 in line 98 of file nucgen.for *****
       ***** Type conflict in DATA statement *****

VMS fortran allows a user to enter character data typed as logical,
byte, integer, real, double precision, dimension, probably complex and
the proper character type "character."  VMS fortran allows character
data to be assigned to these alias types by arithmetic assignment or by
a data statement or non character functions or by using the read
statement.

The use of these Satanic extensions by the VMS implementation of Fortran
scores a 9.73 in the Fortran demolition derby; it is a robust attempt to
demolish the concept of typing!  My compiler quite logically expects
character data to be typed "character."  It is real shame that FORTRAN
is not a standardized language!

Being philosophical about this, I am reminded of the opening words in
"The Tale of Two Cities" by Charles Dickens:  "It was the best of times,
it was the worst of times, ..."   VMS fortran is the best of
compilers, it is the worst of compilers; a language standard is
intended to promote portability, it is intended to promote
profitability, ...

The VAX implementation gives new meaning to the term garbage collection.
Mixing good standards with bad and ugly non standard statements
scrounged from old compilers is an example of misoneism.  It will
compiles everybodies old code.  The basic idea is valid; however,
the incorporation of the garbage collector in a standards conforming
compiler is not.  What is needed is an Exorcist section appended to
the standard.  For example, I could have used an exorcism that
retyped the logical, real, double precision, and byte aliases for
character variables as truly character--not an easy task.  The
Exorcist should produce a new source deck.  

I think that it would be easier to depreciate old features from
a language if an Exorcist existed to do the job; especially a
public domain Exorcist.

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Albert Hybl, PhD.              Office UUCP: uunet!mimsy!mbph!hybl
Department of Biophysics       Home   UUCP: uunet!mimsy!mbph!hybl!ah
University of Maryland                CoSy: ahybl
School of Medicine
Baltimore, MD  21201                 Phone: (301) 328-7940 (Office)
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