[fpc-pascal] Re: using exceptions

[Marcos Douglas]

On Wed, Jan 4, 2012 at 8:35 AM, Lukasz Sokol <el.es.cr at gmail.com> wrote:
>
> On 04/01/2012 00:31, Marcos Douglas wrote:
> [...]
> >> Another interesting article is:
> >> http://www.joelonsoftware.com/items/2003/10/13.html
> >
> > Very interesting and I agree when he say:
> > "I think the reason programmers in C/C++/Java style languages have
> > been attracted to exceptions is simply because the syntax does not
> > have a concise way to call a function that returns multiple values, so
> > it's hard to write a function that either produces a return value or
> > returns an error."
> >
> > If we could return more than one value, ok we (maybe) do not need Exceptions.
> >
> > Marcos Douglas
>
> I find myself often doing either:
>
> function Bla(parameters): integer;
>  - > returns => 0 for success/value returned, < 0 for error and upper layers recognize the error codes
> (this is pretty much like c common usage you can find in c programs)
> or
> function Bla(some_params; out ErrorMessage: string):boolean;
> or
> function Bla(some_params; out ErrorCode: integer): some_type_other_than_integer;
>
> so it's not like you /can't/ return more than one value...
> but you need to prepare yourself for it ;)

Ok, I expressed myself poorly.
When I said: "If we could return more than one value, ok we (maybe) do
not need Exceptions."
I mean: "If we could return more than one value, using a better way
than 'out arguments' or 'array of const', ok we (maybe) do not need
Exceptions in many times".

I know we can use 'out args', 'array' or a object (this provides many
results) but this is not beautiful.
1- out args: we always have a local variable ErrorCode/ErrorMsg (like
your example) and this is boring.
2- array of const: we need 'unpack' the array; memleak could happen; etc;
3- object: we have a local variabel or use 'with' but memleak could
happen any way;

Marcos Douglas