From: rodgers@engcon.marshall.ltv.com (KMRODGERS)
Newsgroups: comp.edu,comp.lang.fortran
Subject: Case Sensitivity (was Re: Small Language Wanted)
Date: 8 Sep 92 14:57:00 GMT
Reply-To: rodgers@engcon.UUCP (KMRODGERS)
Organization: LTV MEG, Dallas, TX

In article <1992Aug25.104211.1@vxdesy.desy.de> pawlak@vxdesy.desy.de writes:
[much quote and reply on the neverending Fortran vs C rwar deleted]
> . . .  And about 70% of the C code I had to work with was 
>badly written because of:
[deleted]
>- making use of case sensitivity (i.e. symbols 'value' and 'Value' in the
>  same program)


I hate contributing to this particular religious warfare (hence the changed
Subject: line), but I think that case sensitivity, WHEN PROPERLY USED, is
(IMHO) a Good Thing.  The simple case cited above shows the bad features of
case sensitivity, but sometimes case is relevant to the problem domain.
Example: most of my work involves air vehicle stability and control
(Advertisement!), and I find myself constantly having to write equations of
motion routines for various analysis tools.  For s&c, several quantities
known as aerodynamic stability derivatives are used.  These are represented
in handwritten or typeset form as as capital "C" followed by various upper
and lowercase subscripts. The case of the subscript is important!  E.g.,
cap "C" sub "L" is lift coefficient, while cap "C" sub "l" is rolling moment
coefficient -- two drastically different quantities.  It is most convenient
and readable (at least to an s&c engineer, and nobody else could/would have
an interest in these particular codes) to directly translate these in my
code(s) as CL and Cl, respectively.  In the absence of case sensitivity,
I must make do with CLIFT and CRM, or something similar.  Sometimes, even the
case of the initial "C" is important.  If I am, say, predicting lift on a
wing, it is even worse, for then I have a quantity known as section lift
coefficient, represented by (lowercase) "c" sub "l"; representing this in 
non-case-sensitive systems (and, as I must often do, staying strictly F77 
with 6-char variable names) would lead to something like CSECTL.  For me
(and, I would venture, most other aerodynamicists and s&c engineers), writing
the three above quantities in our computer codes as CL, Cl, and cl is much more
readable (and a direct translation of the mathematical symbolism) than the
case-insensitive alternative, especially when working in the strict confines
of F77.  (yes, I know that any Fortran which was case-sensitive would almost
certaintly have long variable names, but IMHO it's still more readable mixed
case.)

If one of the goals of a computer language, especially one for scientific
and engineering computation, is to try to preserve as much as possible
and reasonable the natural notations of these fields (a claim that I have
heard Jim Giles make before, and one with which I agree), then I think that
case sensitivity is important, and this is _one_ area where C is superior to
Fortran. (Note the emphasis; I make no other claims in this rwar.)

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Kevin Rodgers  Loral Vought System Co.  rodgers%engcon@uunet.uu.net
Since LTV no longer has Ling, Temco, or Vought, I suggest they change
their name to MBSC (Mostly Bankrupt Steel Company).
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