event-handling approach to errors

[John Wenn]

>I have read both general descriptions of Mesa and the Mesa manual itself.
>I also read an interesting retrospective on the language, which among
>other things said (roughly), "the exception mechanism is too complex
>and gives far too much freedom; it is terribly easy to hang yourself
>(or the next guy who maintains your code) with it, and this happens
>too often for comfort".  I confess it didn't sound that bad to me, but
>they're the ones with Mesa experience.

You're right, it isn't quite that bad.  The entire signal mechanism is very
powerful and general, too much so for most applications.  As with any
powerful feature you can hang yourself if you misuse it, or don't fully
understand it.  On the otherhand, it's nice to have the power when you need
it.  I never used anywhere near the full generality of Mesa signals, but I
did use things that aren't available anywhere else (CLU, Ada, C, etc.).  The
entire subject of how you handle exceptional conditions is not understood.
Mesa provides one extreme.  The right answer probably is a bit more moderate.

/John