Re: Ada exceptions. unchecked?

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

Hyman Rosen wrote:
> 
> Darren New wrote:
> > 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.
> 
> Are we talking about the same thing here? The whole point
> of exceptions is exactly to call malloc without checking
> the result. 

I guess it depends on your philosophy. If the creators of Java were looking
at C and saying "what are common errors that people make" I can see this
being the idea.

> With exception-based error handling, code is
> written as if errors never happen, and resource allocation
> is done with objects which release the resource when their
> lifetime ends.

Well, yes, in languages where objects have a definite lifetime, this is
true. Java isn't like that. Java, instead, has garbage collection. Look at
Eiffel for yet another take on exception-based error handling.

I'm not saying Java's take on this is right, and I'm not saying it's the
best way to handle it. I'm just saying that's how it is. I am explicitly
*not* trying to convince you it's good. I don't even think it's good myself.

> Then if an error does happen, the exception
> propogates out to a handler which usually deals with the
> situation in a high-level fashion, and allocated resources
> between the point of the exception and the handler are
> cleaned up.

Yes, and by declaring what exceptions get thrown, you're telling people who
are calling your library "hey, here's the exceptions you have to handle in a
high-level fashion." Works great, until someone else writes part of the
code, and then they call one of your routines.

-- 
Darren New 
San Diego, CA, USA (PST). Cryptokeys on demand.
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     My brain needs a "back" button so I can
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