The problem is that the words in variables is not
bound to your object.
When objects are made, the spec block is first scanned
for set-words. In your example, there are three set-words
in the spec block, [variables: data: executor:]
These are now the only words which can exist directly in the
object, and they are bound to the object.
Objects can't be arbitrarily expanded or shrunk; you can't add
or remove words. (This is a pity, but I believe it speeds
things up the way it is.)
Anyway, as sad as that sounds, there is a way of wrapping things
up safely in a context. Here is a possible solution:
my-ctx: context [
make-object-spec: func ["Prepare an object spec block from words and
data."
words [block!]
data [block!]
/local result
][
result: copy []
repeat n length? words [append result reduce [to-set-word
words/:n
data/:n]]
result
]
executor: func [variables data program /local object][
object: context make-object-spec variables data
do bind/copy program in object 'self
]
]
; Test
my-ctx/executor [a b] [1 2] [print a + b]
;>> a
;** Script Error: a has no value
;** Near: a
I should also like to know the reason why you
wanted this.
Regards,
Anton.
> Hi list!
> I think I need some "binding" :-)
> this script does not work as I want.
> look :
>
> unset 'a ; just for testing
> unset 'b ;
>
> object: make object! [
> variables: [ a b] ; this block may change during object
> lifetime
> ; so should be always referenced
> data: [1 2] ; data to set, may change too
>
> ; it has to be that way
> ; below is what i want repair
>
> executor: func [ program] [
> use variables [ ; <-- i want to variables to
> be defined
> only here -->
> set variables data ; setting variables
> do program ; executing
> ]
> ]
> ]
>
> testing :
>
> >> object/executor [ print a + b]
> 3
> >>
>
> looks fine, but :
>
> >> print [a b]
> 1 2
> >>
>
> ups! variables are in global context
> please help how to keep them in USE block
> thanks in advance
>
> Karol
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