Re: Ada exceptions. unchecked?

[Darren New <dnew@san.rr.com>]

Hyman Rosen wrote:
> But why does every intervening function in the
> call tree have to state for the record that it knows that
> something it calls may throw such an exception, if it is
> not the place where the exception is handled?

Because it prevents the programmer from ignoring the problem. Note, I didn't
say it prevents the *program* from ignoring it, but the *programmer*.

That is, with checked exceptions, you can't call malloc() without checking
the result, even if every single time you test the program, you manage to
allocate enough memory. 
In other words, it's much the same way that Java refuses to compile somthing
like

int x;
if (y) {x = 5;}
blah(x); /* because x *might* be uninitialized, even if the programmer
            knows that Y will always be true at this point. */

The problem with checked exceptions is that when you're using a lot of
libraries with callbacks and such, the checked exceptions require you to
handle the exception in the *wrong* place. It's difficult to get around in
any clean way, unlike the uninitialized-variable problem.

-- 
Darren New 
San Diego, CA, USA (PST). Cryptokeys on demand.
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