[REBOL] Re: Objects, references & values
From: robert:muench:robertmuench at: 19-Dec-2001 13:55
> -----Original Message-----
> From: [rebol-bounce--rebol--com] [mailto:[rebol-bounce--rebol--com]]On Behalf Of
> Romano Paolo Tenca
> Sent: Tuesday, December 18, 2001 7:41 PM
> To: [rebol-list--rebol--com]
> Subject: [REBOL] Re: Objects, references & values
> nameref: in obj1 'name
>
> Now 'nameref is a pointer to a word which is linked to the field called "name"
> in the object 'obj1.
Hi, yeah that's right but how do you search for the value of nameref? With this
you can't use the hash! datatype because you don't have a value hash! can use.
That's why I would like to have a value which I can add to a hash! that's
updated when the referenced value changes.
I know that's not easy to achieve. Even with C++ and the STL container you have
the same problem. You can either use the pointer address to your value as
hash-key, or you can use the value as hash-key. What to do if a key-value
changes? Well, search it, remove it and add the new key-value.
The problem to solve is that you have to be sure to keep everything in sync. In
C++ you can do this by using member-functions and makeing the data-members
private to the object. This ensures that none will be accessed/changed directly
without executing the house-keeping code.
> Another method:
> x: bind [name] in obj1 'self
>
> Now x is a block which contains as the first item the word 'name linked to the
> object obj1:
>
> x: bind [name] in obj1 'self
> == [name]
> >> get first x
> == "robert4"
Ok. BTW: I just had an idea. When using 'bind you can't see from the word, to
which it is bound. Howabout having "bind [name] in obj1 'self" return obj1/name?
This would be very logical IMO.
As said, the biggest problem I currently have is that I would like to have a
simple way to use the well known datastructures for managing objects, values
etc. and being able to search, store etc. those datastructures.
BTW: What happens if those structures are stored? Will Rebol be able to resolve
the linking again? I don't think so... this implies that a datastructure loader
is needed to setup all those references again. Robert
