Re: RPG IV program - comments requested

[Jim Langston <jlangston@xxxxxxxxxxxxxxxx>]

Okay, now it makes sense.  It is the same way languages such as
Pascal do it.

The prototype at the top just tells the compiler - Hey compiler,
I have this procedure in my program, set aside some memory for
it's location.  That way when the compiler runs across a call to
the procedure before it sees the actual procedure code it knows
what to do, it points the call to the memory location it had set
aside to it, something like a pointer.

In Pascal Prototyping was not required, but I found that I would
start juggling around my subroutines and functions every time I
modified them to make sure that the functions that called other
functions were found in the code first.  A big pain, then I started
prototyping all of them.

Regards,

Jim Langston

Scott Klement wrote:

> Jim Langston <jlangston@conexfreight.com> wrote:
> >
> > The Prototype is only needed for the compiler, if you had many
> >  callable subroutines in your source code, you would put all the
> >  Prototypes at the top, but but each program interface by each
> >  subroutine?  Wait, that doesn't make since, since all D specs have
> >  to be declared at the opt of code anyway!
> >
>
> Actually, you have seperate D-specs for every procedure.
>
> The procedure interface should always be declared (IMHO) in the first
> D-specs of your procedure definition.
>
> Furthermore, if your procedure depends on another procedure thats not
> in the same module, the prototype for THAT procedure should be
> /COPY-ed into the D-specs for the procedure that needs it.  The
> variables that are needed within a procedure should also be defined
> as local to that procedure...
>
> This way, you can easily copy that procedure, make small changes, and
> have a working routine...   The code is reusable!   Global definitions
> ruin this.  Plus, the fewer inputs and outputs to the procedure make
> it easier to debug and maintain... (again, thats IMHO)
>
> Very powerful concepts, here, but they take a little bit of working
> with to get used to :)
>
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