Re: [stack] Properties of Concatenative langauges and Forth
John Nowak <[email protected]>
| Newsgroups | gmane.comp.lang.concatenative |
|---|---|
| Message-ID | <[email protected]> |
On Jan 2, 2009, at 11:57 PM, Christopher Diggins wrote: > On Fri, Jan 2, 2009 at 10:20 PM, John Cowan <[email protected]> wrote: > >> Christopher Diggins scripsit: >> >>> Talking about data-flow in the context of Joy is incorrect. A Joy >>> program has no data, only functions. You'll see what I mean below. >> >> Well, sort of. 5 is a number in Joy, even if it's a function too. >> As a function, it can be applied to the stack; but if it's on the >> stack, > > As a syntactic phrase in the Joy language, the symbol "5" has one > meaning: it is a function that takes a stack as input and returns a > copy of the input stack, with a value "5" on top. I agree. > Dually we can explain it is an instruction that pushes a value "5" > on a shared stack. Not necessarily in Joy, unless you also describe 'infra' as something which changes which stack is the "shared" stack until some particular quotation in finished being evaluated. I think that's pretty clumsy compared to '{S} [F] infra => {S F}'. - John