Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!gatech!purdue!haven!umbc3!mbph!hybl
From: hybl@mbph.UUCP (Albert Hybl  Dept of Biophysics  SM)
Newsgroups: comp.lang.fortran
Subject: Re: Character aliases are Satanic exten
Summary: Do ANSI committees communicate with each other?
Message-ID: <596@mbph.UUCP>
Date: 19 May 89 23:05:57 GMT
References: <592@mbph.UUCP> <50500128@uxe.cso.uiuc.edu> <105003@sun.Eng.Sun.COM> <1515@hudson.acc.virginia.edu>
Organization: University of Maryland, School of Medicine, Baltimore, MD 21201
Lines: 66

In article <1515@hudson.acc.virginia.edu> from
gl8f@bessel.acc.Virginia.EDU (Greg Lindahl), Greg protests:

>Thank you for posting my mail verbatim without asking first.
Greg, to you, I extend my most sincere apology.

>I often write mail off the top of my head; before I post I
>double-check my information.
Thank you for the flummery :-(

I hope the dialogue that flows from my unintentional breach of
etiquette will help identify the reasons why "Fortran 77 is weaker
than other modern languages in its handling of character strings, ..."

>...                checking my _Aipsletter_ vol 8 # 3, a magazine
>published by the AIPS people, I find that they recently did convert
>their Satanic characters into a different form.

That is good news.  How does one subscribe to _Aipsletter_?

>...                         just because all the computers you use
>have the non-standard extension that character and other types can
>coexist doesn't mean that the Standard says so.

Sigh, the SVS-fortran compiler I am using doesn't allow character
arrays or strings to exist in the same labeled common with integers
and reals; this rates a 6.31 in the demolition derby.  I would like
to be able to do something like the following:
      PARAMETER (KMAX=a_big_number)
      PARAMETER (JMAX=4*KMAX)
      COMMON /ARCHIV/ ARRAY
        INTEGER*4 IARRAY(KMAX)
        REAL*4 ARRAY(KMAX)
        CHARACTER*(JMAX) DNA
        CHARACTER*1 AND(JMAX)
        EQUIVALENCE (IARRAY,ARRAY,DNA,AND)
By using integer pointers, one could store or retrieve information
from a large archival record containing mixed types.  A simple
WRITE N, ARRAY should copy the whole record to an I/O device.
This allows a hacked dynamic storage scheme.   The only problem
is that it is not portable for many disparate reasons.

First, as the _Aipsletter_ points out, the standard doesn't allow
>"... character strings [... to] occur with other data types in,
>for example, commons and I/O records ... "
I have not encountered a computer that requires this separation
because of any hardware limitation.  Second, most implementations
severely limit the length of a character string.  Third, some
implementations limit the number of bytes that can be written to
a binary I/O record.

RM-fortran on an IBM PC/AT limits a binary write to 1032 bytes;
the XLA+ compiler on our AT&T 3B2 limits the length to 256 bytes.
This renders the binary write statement impotent and hence gets
rated at 3.87 in the demolition derby.  I think it was short
sighted of the X3J3 committee not to require implementors to
use spanned records as defined in ANSI X3.27-1978 (pages 24-26).
Don't the various ANSI committees communicate with each other?

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Albert Hybl, PhD.              Office UUCP: uunet!mimsy!mbph!hybl
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