[Info-vax] puzzled by DCL symbol substitution

[AEF]

On Jan 8, 5:07 am, hel... at astro.multiCLOTHESvax.de (Phillip Helbig---
undress to reply) wrote:
> In article
> <6ae68ad7-98f2-4935-9eaa-dd35266f7... at n6g2000vbg.googlegroups.com>, AEF
>
> <spamsink2... at yahoo.com> writes:
> > > I once read about a contest to create the smallest self-reproducing
> > > program.  Someone submitted an empty file.  They subsequently amended
> > > the rules to disallow this.
>
> > Huh? I'm missing something here. Please explain.
>
> Depending on whether an empty file is the same as no file, an empty file
> is a self-reproducing program since when run it produces nothing.

But when you run a empty file you don't get another empty file.
Actually, to be self-reproducing the file would have to run itself!
Nobody runs a cell, for example. The cell runs itself.

OK, let's assume you allow that another entity runs the file in some
manner without breaking the rules. (You'd need different rules, of
course.)

An empty file is not the same as no file. Just like zero is not the
same as the empty set. Just like the empty set contains exactly zero
elements, the empty file contains exactly zero data, or zero bytes, or
zero records -- the idea being that either contains exactly zero of
any kind of items you choose. Therefore it is not self-reproducing.

Ah, but there is a difference. You can have multiple empty files, but
you cannot have multiple empty sets.

Also, if you make enough empty files you will fill the disk. No matter
how many "non-files" you have, you won't fill the disk.

An empty file is referenced by a header, which itself is something.
The entity called "no file" does not require a header and in fact has
no such entity associated to itself.

AEF