[REBOL] Re: Nested objects
From: joel:neely:fedex at: 27-Jun-2001 3:31
Hi, Gavin,
Gavin F. McKenzie
wrote:
> Say, I've got a bunch of nested objects that I setup
> conveniently using syntax like:
>
> obj: make object! [
> foo: 1
> bar: 2
> nested-object:
> make object! [
> abc: 3
> xyz: 4
> ]
> ]
>
Flo: "Doctor, it hurts when I do this!"
Moe: "Well, then don't do that!"
Seriously, we had a long thread several weeks back on the
topic of "nested objects". This quickly gets into some VERY
subtle (IMHO) aspects of REBOL behavior.
> Now, I want all of my inner objects to have a property that
> ties them to their parent objects...
>
The only way I know how to make sense of the terms "parent
object" and "child object" for code like your sample is the
issue of which context(s) was/were used to resolve words that
were evaluated during the construction of NESTED-OBJECT.
> Maybe I'm missing something rather straightforward.
>
Not to my knowledge. Given
>> obj1: make object! [foo: 1 child: none]
>> obj2: make obj1 [foo: 2]
>> obj3: make object! [baz: 42 parent: none]
>> obj1/child: obj3
>> obj2/child: obj3
>> obj3/baz: 17
== 17
>> source obj1
obj1:
make object! [
foo: 1
child:
make object! [
baz: 17
parent: none
]
]
>> source obj2
obj2:
make object! [
foo: 2
child:
make object! [
baz: 17
parent: none
]
]
I think that tree-walking (or other relationship-management
at run time) is the best way to determine whether
obj3/parent: obj1
or
obj3/parent: obj2
is what you need at any given point.
-jn-
------------------------------------------------------------
Programming languages: compact, powerful, simple ...
Pick any two!
joel'dot'neely'at'fedex'dot'com
