[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: openr and /get_lun

In article <8dfqbo$ep1$2@hammer.msfc.nasa.gov>, 
mallors@ips1.msfc.nasa.gov (Robert S. Mallozzi) wrote:

> In article <38FB4B75.936477C5@astro.cornell.edu>,
> 	"J.D. Smith" <jdsmith@astro.cornell.edu> writes:
> > "Robert S. Mallozzi" wrote:
> >> 
> >> I sure wish we had a boolean datatype - the mistake of
> >> using something like "IF (NOT error) THEN" is one that
> >> is really a pain to find, although it certainly makes
> >> your code much more readable.
> > 
> > We don't need a boolean data type... we need IF to examine not just the 
> > first
> > bit of the value, but the whole thing, and use C's 0=false, anything 
> > else =true
> > paradigm.  Here's hoping.
> > 
> > if NOT 2 then print,"this isn't right!"
> This would certainly break backward compatibility - there 
> has to be someone, somewhere that relies on the fact that in
> IDL, odd = true and even = false !  I feel as you do that this 
> was a design mistake made a long time ago, in a programmer's
> mind far, far away...
> Regards,
> -bob

    One man's mistake is another's feature (or something like that).

    The "low bit 0 = false, low bit = 1 true" convention is from VMS 
(way back in the pre-Alpha days, even.... what did they call those 
things, VAXen? VAXes?), with the more significant bits yielding addition 
information on the specific error or (in the case of oddness) warning, 

    No doubt due to operant conditioning programming VAX system 
services, I find this convention more useful than C's convention.

    Chacun a son error convention....

                  Joe Gurman

Joseph B. Gurman / NASA Goddard Space Flight Center / Solar Physics Branch /
Greenbelt MD 20771 / work: gurman@gsfc.nasa.gov /other: gurman@ari.net

Government employees are still not allowed to hold opinions while at work,
so any opinions expressed herein must be someone else's.