[REBOL] Re: Words escaping from context! help needed!
From: ammon:johnson::gmail at: 11-Feb-2005 12:08
Gabrielle is right, COMPOSE will do what you want but it gets slightly
more complex if it want to really work dynamically...
example: make object! [
variables: [a b]
data: [1 2]
executor: func [program] [
use variables compose/deep [
set [(variables)] data
do bind load [(program)] (to lit-word! first variables)
]
]
]
example/executor [print a + b]
This is a subject (context and binding) I've been meaning to write an
article on but there just aren't enough hours in a day...
HTH
~~Ammon ;~>
On Fri, 11 Feb 2005 18:02:05 +0100, Volker Nitsch
<[volker--nitsch--gmail--com]> wrote:
> On Fri, 11 Feb 2005 13:58:14 +0100, Karol Go=C5=BAli=C5=84ski
> <[kgozlin--neokartgis--com--pl]> wrote:
> >
> >
> > I set them to none, but it does not help, see
> >
> > unset 'a
> > unset 'b
> > object: make object! [
> > variables: [ a b]
> > data: [1 2]
> > executor: func [ program] [
> > use variables [
> > a: b: none
> > set variables data
> > do program
> > ]
> > ]
> > ]
>
> when i wrote: "make object!" detects only set-word in top-level"
> i meant the top-level block. "make object!" does not look inside inner
> blocks. so this:
> make object![ inner-block: [ a: b: none ] ]
> would not work. and you do similar with executor. but this:
> make object![ a: b: none ]
> works. "make object!" sees the set-words and makes them local for
> everything inside the block. so the 'a 'executor will be bound to the
> object and no longer be global.
>
> its also not required to set them to none, only that they appear as
> set-words in the top-level block. so 'executor is local too, because
> the appears "executor:".
>
> >
> > >>
> > >> object/executor [ print a + b]
> > 3
> > >> print [a b]
> > 1 2
> > >>
> > still 'a and 'b are in global context
> >
> > but I want also do such things :
> >
> > object/valiables: [ x y]
> > object/data: [3 4]
> > object/executor [ print x * y]
> >
> > 12
> >
> > so I can not rely on constatnt variables
> > function foreach does similar thing
> > but i have no idea how
> >
> > thanks for reply
> >
> > Karol
> >
> > --
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> >
> >
>
> --
> -Volker
>
> "Any problem in computer science can be solved with another layer of
> indirection. But that usually will create another problem." David
> Wheeler
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--
Enjoy!!
~~~ Ammon ~~~
~ Sui Generis ~
~~~~ ;~> ~~~~
