Re: [stack] So what is a concatenative language?

Christopher Diggins <[email protected]> wrote:
> Hi William,

> I have responded inline below, but as a result of your suggestions I
> have revised the definition:
> http://cdiggins.com/2007/04/28/a-definition-of-concatenative-languages-refined/

Ah! That seems plausible. It seems intuitively right (not an indicator
of truth, but certainly a good thing for a definition). It's
definitely simple and complete, and clearly distinguishes flat from
non-flat.

There's a pernacious typo in your definition, though. You say that "x
represents one or more non-terminals". Of course, you mean that it
represents one or more _terminals_. :-)

Also, rather than "no other production rules are allowed", I would
suspect that "no other forms of production rules are allowed."

> > > "Flat concatenative languages are simply the set of all strings over a
> > > given alphabet".
> > Gut feeling: I think you're right (of course, ignoring semantics such
> > as typechecking).

Clearly, your new definition is better for flat concatenative
languages, since it implies that they are clearly a subset of all
concatenative languages.

> Thanks for your feedback!

You're quite welcome -- thank you for the formal definition.

I would like to explore the formal semantics a little, though. I don't
know what exactly a "state function" is, for example.

Out of curiosity, and as a first attempt at applying this definition,
is a regular expression specification language concatenative?

> - Christopher

-Billy