Clarity vs. code reuse/generality

[Tim Rowe]

2009/7/4 kj <no.email at please.post>:

> Precisely.  As I've stated elsewhere, this is an internal helper
> function, to be called only a few times under very well-specified
> conditions.  The assert statements checks that these conditions
> are as intended.  I.e. they are checks against the module writer's
> programming errors.

Good for you. I'm convinced that you have used the assertion
appropriately, and the fact that so many here are unable to see that
looks to me like a good case for teaching the right use of assertions.
For what it's worth, I read assertions at the beginning of a procedure
as part of the specification of the procedure, and I use them there in
order to document the procedure. An assertion in that position is for
me a statement to the user of the procedure "it's your responsibility
to make sure that you never call this procedure in such a way as to
violate these conditions". They're part of a contract, as somebody
(maybe you) pointed out.

As somebody who works in the safety-critical domain, it's refreshing
to see somebody teaching students to think about the circumstances in
which a procedure can legitimately be called. The hostility you've
received to that idea is saddening, and indicative of why there's so
much buggy software out there.
-- 
Tim Rowe