Re: incomplete languages

["Alexandre E. Kopilovitch" <aek@vib.usr.pu.ru>]

"Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> wrote:
> > every language that is rich enough is necessarily incomplete.
>
>Incomplete for what?

Precisely that. I mean that this is the point: if, say, some generic construct
corresponds to a general notion that belongs entirely to the problem area (but
has various specialization or flavors) then there is no reason to climb into
meta-language. But if a generic construct is designed specifically for reuse,
then turning to meta-language may be essential for adequate description, because
"reuse" itself is surely a meta-notion. 

> > If a language should be complete for everything, then
> > meta language is also no answer, because it in turn will be also
> > incomplete.

Certainly yes, meta-language will be also incomplete "for everything".
But with it the base language may appear complete. For example, the base
language may be complete for any particular programming case; assistance
of suitable meta-language makes it complete for more general issues (design
considerations, program comparison etc.); but further generalizations (well,
investigation of methodologies of program comparsion -:) may reveal cases that
can't be adequately described with our meta-language.


Alexander Kopilovitch                      aek@vib.usr.pu.ru
Saint-Petersburg
Russia