Path: utzoo!utgpu!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!rutgers!uwvax!tank!mimsy!eneevax!haven!umbc3!mbph!hybl
From: hybl@mbph.UUCP (Albert Hybl  Dept of Biophysics  SM)
Newsgroups: comp.lang.fortran
Subject: An exercise in futility (was Results of the UGLY code)
Keywords: Cumulative_Annual_Pocket_Part
Message-ID: <583@mbph.UUCP>
Date: 30 Dec 88 19:22:54 GMT
Organization: University of Maryland, School of Medicine, Baltimore, MD 21201
Lines: 54


In message-ID: <1750@devsys.oakhill.UUCP>, Steven R Weintraub, 
Motorola Inc. Austin, Texas--cs.utexas.edu!oakhill!devsys!steve,
summarized the results of his "UGLY" code problem run on about 24
different compilers.  The test problem was:

>      K = 0
>      DO 10 I = 1,10
>        IF (I.EQ.1.OR.I.EQ.5) GOTO 10
>        DO 10 J = 1,10
>          IF (J.EQ.3) GOTO 10
>   10 K = K + 1
>      PRINT *,K
>      END

Half of the fortran implementations produced an ERROR diagnostic;
the other half gave numeric answers having the disparate values 80,
82 or 92.

Steve has shown that the USENET can be used to rapidly discover
ambiguities in a language standard.  Discussions in this newsgroup  
can propose corrective language to eliminate ambiguities from
the standard.  The real problem is how to incorporate the new
language in a standard that has been chiseled in stone?  Must
we wait for FORTRAN8x? :-(

After our law makers write and pass laws, the laws appear in a
publication of state or federal statutes.  The legislature
will try to correct a discovered flaw or ambiguity in a law
during their next session.  In rare cases, a special
session may be called to tackle the problem.  Ambiguities in
the law can also be resolved by the courts.  All new laws,
recently revised laws and notes of court cases are placed in
the "Cumulative Annual Pocket Part" which is placed in the
back of the appropriate volume of the statutes.

The purpose of the Fortran ANSI X3.9 1978 standard "is to
promote portability of FORTRAN programs for use on a variety
of data processing systems."  The result of Steve's survey
shows that not even a simple double do loop is immune to
ambiguity when tested for horizontal portability.  His example
and others (see Fortech Forum, Vol 2 pages 5-6; Fortran
Forum, Vol 4 pages 19-20 and Fortran Forum Vol 6 pages 10-11)
proves that computer language standards need a "Cumulative
Annual Pocket Part."  Without it, the hope for a horizontally
portable standard is an exercise in futility.

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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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