[EMAIL PROTECTED] wrote:
>
> Hi, Joel,
>
> although not been asked, trying to answer some questions.
>
> 1) The model of binding Gabriele (not Gabrielle)
[sigh...] It seems I am unable to type these days without making a
typo! [My apollogies, Gabriele!]
>
> proposed was proposed as a
> hypothesis, that could explain the Rebol behaviour. Since then it has
> succeeded to explain every situation encountered and to make valid
> predictions, so it's validity is much less questionable than validity of any
> other binding model proposed.
>
Gabriele's email to which I was responding certainly expressed some
ideas that were helpful to me. My questions were intended to help me
understand it better. I appreciate your assistance in that regard.
So, let me do a sanity check by attempting to answer the questions I
raised, based on my understanding of what you and Gabriele have said.
> > You've persuaded me that one part of that concept does NOT apply to
> > REBOL -- that of searching a chain of environments...
There is no "chain of environments". Each word directly refers to its
own context.
> > >> e
> > == [a b c]
> > >> print e
> > 1 2 12
> > >> c
> > ** Script Error: c has no value.
> > ** Where: c
> > >> same? 'c third e
> > == false
The 'c at the third element of 'e ['s value] had been bound to the
local context of a function (value of 'f), and was therefore a
different word from a global 'c (although spelled the same).
> > >> h: func [][bind e third e print e]
> > >> h
> > 20 21 12
> >
> > Hmmmm. Within 'f (where we've bound 'c) the words 'a and 'b would
> > have evaluated globally. However, attempting to bind 'e back to
> > that context doesn't restore 'a and 'b (in e!) to refer to the
> > global 'a and 'b.
Precisely because global 'a and 'b aren't in the context to which the
third element of 'e ['s value] is bound, and therefore aren't changed
by the 'bind within 'h ['s value].
> > >> bind e 'f
> > == [a b c]
> > >> print e
> > ** Script Error: c has no value.
> > ** Where: c
> > >> a
> > == 1
> > >> print first e
> > a
> > >> print get first e
> > 1
The last one is the only one I'm still trying to understand. Running
the following (in a fresh REBOL console) highlights my question.
>> a: 1
== 1
>> b: 2
== 2
>> e: [a b c]
== [a b c]
>> print e
** Script Error: c has no value.
** Where: c
>> f: func [n /local c][c: n bind e 'c print e]
>> f
** Script Error: f is missing its n argument.
** Where: f
>> f 99
1 2 99
>> print e
1 2 99
>> bind e 'e
== [a b c]
>> print e
** Script Error: c has no value.
** Where: c
What I think you've said is that the bind in f affects only the
third element of e because the other elements refer to words not
in the context used for the bind. c is bound, but a and b are
left alone.
OTOH, the last bind above affects all of a, b, and c, because it
the target context is the global context. Therefore, a and b
get bound back to a context where they already have values, but
c gets bound to a context where it does NOT have a value.
Did I interpret your description correctly?
Thanks for your feedback (and patience) !
-jn-
