Re: [stack] Flat sublanguages of concatenative languages

Manfred Von Thun <[email protected]> wrote:
> Suppose X, Y, Z are languages, X is a sublanguage of Y, and Y is a
> sublanguage of Z. One might write this as X <= Y <= Z.

> Now let X, Y, Z be concatenative languages. Let P be ³is flat².
> Given the flatness of Y, can we infer anything about the flatness
> of X or of Z? My immediate reaction would be ³of course X will be
> flat² and ³we can¹t say anything about the flatness of Z². But
> I have learnt to mistrust my immediate reactions. Any views?

This depends on our definitions. If I read things correctly, a
sublanguage of a flat language _must_ be flat. Of course, a
superlanguage of a flat language need not be flat (and may not be
concatenative).

For example, Joy is a concatenative language, but the entire thing
(considered with all its definition syntax) is not purely
concatenative. (There's nothing wrong with that!) So in that sense,
the concatenative language we refer to as Joy has a non-concatenative
superlanguage that we use every time we program in it.

>   - Manfred

-Billy