Re: Ada cost breakpoints (was Re: Air Force helping to undermine Ada)

[mfeldman@seas.gwu.edu (Michael Feldman)]

In article <65260@mimsy.umd.edu> alex@cs.umd.edu (Alex Blakemore) writes:
>In article <9303151702.AA01402@manta.nosc.mil> mshapiro@MANTA.NOSC.MIL (Michael D Shapiro) writes:
>> for smaller programs with shorter life
>> cycles, Ada might cost more to use over the full life cycle.
>> Has anyone done a study to find these breakpoints?  One pair I've
>> heard mentioned as the appropriate minima for Ada are 500K
>> source lines of delivered code and/or seven years life cycle.
>
>I have no study to point to, but from experience 500K SLOC is way too high
>for a minimum breakpoint to Ada.  The breakpoint depends on the complexity
>and number of people involved.  I dont know about you, but things start
>to seem complex to me much closer to 30K than 500K lines.
>Even 30K lines of C is a pretty frightening thought.

As a 20-year Snobol4 nut (Snobol4 is one of the languages Shapiro mentioned
as good for quickies), I feel qualified to describe something I did yesterday.
I needed to generate a file of calendar data to use in a little system I'm
developing for the department. Basically I needed a set of lines of
form <day of week> <month name> <day in month>, for several years.

I briefly considered doing it manually, or generating the file from a
Snobol4, C, or Ada program. As it turned out, I was able to use package
Calendar, along with a little student-written package that finds the
day of the week a given date falls on, and generate this file with a
1-shot Ada program in about 30 minutes. 

The program compiled and ran the first time; refining the output took 
a couple of change cycles.

Mostly, the changes were required to display the days and months
with initial caps. My first cut was to use Enumeration_IO, but
enum literals can be written only in full upper or full lower case,
and I thought this was unesthetic after seeing it "in print."

So I gave up on Enumeration_IO and used strings instead. Yes,
I know there are tricks one can use to get initial caps, but I
didn't want to spend the time - after all, it was a one-shot.

Given my two reusable components - Calendar and my own package -
I found Ada to be a very productive way to write a quickie.

No doubt someone will claim that it would have been just as fast with 
C or maybe PERL. Sure - no problem there. But the point of this post
is to emphasize that with a good personal collection of Ada components,
together with the "free" stuff like Calendar, Ada does NOT (read my
lips: NOT) require a big human-time overhead to write a 1-shot. Don't
believe all this trash you hear. What counts is how much reusable
functionality you have lying around. 

No doubt you will find better ways of doing this program - so would I 
if I wished to spend the time. But I had 30 minutes to do it, and I 
was done on time. So don't flame me - I brought the sucker in under
budget :-)

BTW - I used Ada/Ed. And the program was so simple - given the packages -
that I will now assign it to my freshmen as a 1-week-turnaround project.

Mike Feldman
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Michael B. Feldman
co-chair, SIGAda Education Committee

Professor, Dept. of Electrical Engineering and Computer Science
School of Engineering and Applied Science
The George Washington University
Washington, DC 20052 USA
(202) 994-5253 (voice)
(202) 994-5296 (fax)
mfeldman@seas.gwu.edu (Internet)

"The most important thing is to be sincere, 
and once you've learned how to fake that, you've got it made." 
-- old show-business adage
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