Re: [stack] Type systems and Joy
David R W Denny — 2000-05-22 06:07:41
On Mon, 22 May 2000, you wrote:
> Is Joy an elephant? Are we the blind men?
>
> "[foo]" does not mean "push 'foo' onto the stack". It means "push
> '[foo]' onto the stack." '[1]' already means something: to suggest
> that it should mean what '1' means now, and that we shouldn't use the
> latter, is so wrong.
>
> The difficulty may be this: [x] always means "push [x] onto the
> stack", but x means "push x onto the stack" if x is an integer, but
> not if x is 'dup'.
>
> sr
My one cent::
you are going to distinguish, in general terms, between an instance of an
object named in your code, and an instance of a named object whose name
is itself known to be an instance of an object named in the code ??
could be put more simply (fx value of data item 1 , versus value of (local)
data item pointed to by data item 1) - but not sure of local terminology - no
intention to offend ;-)>
*grin* from the same body of stories comes the one where the king has I think a
dry throat, and each successive doctor (by appointment or otherwise) gives a
remedy whose intention is to counteract the preceding remedy.... as can be
imagined, the poor king is in a bit of a mess at the end of it all ;-)>
Best Wishes
David
--
Take Care, Take It Easy
Dave Denny:r2d2:Croydon, UK
ama sua, ama qhella, ama llulla <Quechua>
srenner@mail.ru — 2000-05-22 15:06:04
> you are going to distinguish, in general terms, between an instance
of an
> object named in your code, and an instance of a named object whose
name
> is itself known to be an instance of an object named in the code ??
>
> could be put more simply (fx value of data item 1 , versus value of
(local)
> data item pointed to by data item 1) - but not sure of local
terminology - no
> intention to offend ;-)>
>
> Dave Denny:r2d2:Croydon, UK
I don't understand. Instance? Named object? Object? Code? Instance of
a named object whose name is itself known to be an instance of object
named in the code? Joy is linear, has no names, and can be implemented
without using a dictionary.
sr
sr
wtanksley@bigfoot.com — 2000-05-22 17:25:45
From:
srenner@... [mailto:
srenner@...]
>Is Joy an elephant? Are we the blind men?
It would seem that way :-).
>The difficulty may be this: [x] always means "push [x] onto the
>stack", but x means "push x onto the stack" if x is an integer, but
>not if x is 'dup'.
You state the problem well. Literals are a special case, and this fact
makes many things more complicated in Forth.
>sr
-Billy
wtanksley@bigfoot.com — 2000-05-22 17:37:03
From: David R W Denny [mailto:
david@...]
>you are going to distinguish, in general terms, between an
>instance of an
>object named in your code, and an instance of a named object
>whose name
>is itself known to be an instance of an object named in the code ??
Could you repost this, in different words? I don't understand this
paragraph, although I can completely parse it. The paragraph after it I
can't even parse.
>David
-Billy
Massimo Dentico — 2000-05-22 19:20:34
wtanksley@... wrote:
>
> From: srenner@... [mailto:srenner@...]
>
> >Is Joy an elephant? Are we the blind men?
>
> It would seem that way :-).
>
> >The difficulty may be this: [x] always means "push [x] onto the
> >stack", but x means "push x onto the stack" if x is an integer, but
> >not if x is 'dup'.
>
> You state the problem well. Literals are a special case, and this fact
> makes many things more complicated in Forth.
>
> >sr
>
> -Billy
A proposal without much thought (perhaps wrong).
If X is not an integer could be "push X onto the stack,
remove from the stack and evaluate it":
(*1*) X == X i (* "i" means evaluate *)
(*2*) joy == i (* in
http://www.latrobe.edu.au/www/philosophy/phimvt/j10int.html *)
(*3*) X == X joy (* from 1 and 2 *)
mmm .. if X is an integer is probably the same (depending on the
semantics of "joy").
I don't have a strong mathematical background but this seems
to mean that a Joy program is the fixed point of the equation 3
or that the meaning of X is the evaluation of X under the "joy"
combinator (the interpreter of Joy).
Is it useful and correct this point of view?
--
Massimo Dentico