Re: Questions on implementations and specs

["chris.danx" <chris.danx@ntlworld.com>]

"Aidan Skinner" <aidan@velvet.net> wrote in message
news:slrn9sdhka.hnq.aidan@crushed.velvet.net...
> On Thu, 11 Oct 2001 18:03:41 +0100, chris.danx <chris.danx@ntlworld.com>
> wrote in <Ahkx7.4857$i14.643289@news2-win.server.ntlworld.com>:
>
> >  documented).  I was under the impression that the programmer should not
need
> >  to look at the implementation *in most cases* (of course there are
cases
> >  when we do need to look at the implementation).
>
> This is one of the areas where I like Java over Ada. The raises statement
> and it's enforcement by the compiler are, IMO, very very useful.

It might be nice to see some optional method of specifying exceptions that a
routine may generate (need not specify them all), like

name_error : exception;

procedure open (file : file_type)
   with exception (name_error, blah_blah);

but I think the Java 'must specify exceptions' is a pain mostly (even though
it helps with documenting exceptions).

> Being able to see clearly what each method/function/procedure can generate
> is a great help, although they should be documented by the package spec,
> it's not always...

There are a lot of implied exceptions (like constraint_error) which don't
need documentation but in some cases where a condition could arise that is
important and there is no alternative method to detect the condition, the
exception signalling the condition should be documented, IMO.



Chris