Clarity vs. code reuse/generality

[Tim Rowe]

2009/7/9 kj <no.email at please.post>:

> Thanks for the encouragement.

[snip]

> into code.  And by this I mean not only assumptions about the
> correctness of their code (the typical scope of assertions), but
> also, more broadly, assumptions about the data that they are dealing
> with (which often comes from external sources with abysmal quality
> control).

There we diverge. A lot. If "correctness of the code trumps everything
else" (in fact, if it matters at all) and the external data has
"abysmal quality control" then it *must* be checked for correctness
before it is used. If it is not, you have no idea whether your output
is correct or not. And assertions *will* *not* reliably provide that
checking (because they may not be executed). You *must* actively check
the data, using good old-fasioned "if" statements and so on, because
not to do so is to declare that you *don't* care about correctness.
You *know* the input is often wrong, but you're not bothering to check
it?

-- 
Tim Rowe