[REBOL] Fwd: Re: Why should I copy ?
From: moliad:g:mail at: 5-Oct-2009 16:10
I had replied 2 weeks ago, but it seems my post never got to the mailing list,
here it is... again.
On Thu, Sep 24, 2009 at 12:22 PM, Sunanda <dhsunanda-gmail.com> wrote:
> Lesson: use COPY. it associates the word 'b with a fresh [] each time
>
> =====
......
> >
> This behaviour can take a while to get used to ;)
>
I just want to point out that this isn't' a bug, its a feature by
design. =A0All rebol series are mutable, so they aren't copied each time
they are assigned to a variable, like in most other languages, python
for example.
this means a big boost in assignment speed and it also means that series
can be shared amongst many references by default, another thing which
allows many optimizations. =A0Most other languages will create
independent versions of series every time they are assigned, and
sharing them becomes difficult.
remember my function hack example, it doesn't copy the block created
as storage for the function value... this is an example of how this
can be used as the feature it is.
this being said, there are some variants of function! creation code
out there which creates a new independent context each time the
function is called, but that is slow and may cause memory leaks in
some use cases...
better just to use copy all the time, this way its explicit and you
realize you have full control.
-MAx
