Re: compilation time [was Re: Magnavox consultant]

[eachus@spectre.mitre.org (Robert I. Eachus)]

In article <38afut$8m9@news.delphi.com> tmoran@bix.com writes:

 > I can't imagine attempting to maintain a package with more than 500
 > 'with's, so perhaps compilation time has an exponent significantly
 > greater than one initially, but decreasing to one at 1,000
 > packages.  Who has statistics?  (And does C, what with 'include's,
 > scale similarly?)

   Not statistics, but a rule of thumb.  If package specifications
average more than six withs, or if there are more than about ten on
the package bodies, or if more than 16 total apply to a particular
subunit, your coupling and cohesion are out of control, and a project
wide design review is in order.

   Again the above is not a set of magic numbers, and in any case they
are averages, not per unit limits, but these values seem to be around
the knee of the (Ada 83) curve.  I have no idea yet what the numbers
are for 9X.  Child units both make counting more difficult, and mean
that there may be significantly more with clauses in the same (Ada 83)
design, because massive packages have been decomposed into subsystems
with many child packages.  Should you count an entire subsystem as one
"with"?  I don't know, I have trouble enough in Ada 83 eliminating
double counting.

--

					Robert I. Eachus

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