[REBOL] Re: Newbie Q: Cropping text
From: chalz:earthlink at: 7-Jul-2002 23:56
> To Charles:
>
> > Personally, I have a hard time working with
> > series! with next and skip and tail and so forth.
> > A pointer to a list element which I cannot see irritates me.
>
> I don't understand what you mean. That is, what do mean by see?
For instance, in C, I would have something like int idx; wherein I could use
array[idx]; and move around by increasing and decreasing the index marker. How
can I optically see where 'next will put me without evaluating it? How can I
find out where REBOL believes itself to be in a series! ? Does REBOL think
it's at the first value, the second, the third, etc? How can I find out?
> I suppose you could say that REBOL does not make pointers an explicit
> datatype, and I reckon that is a good thing. It is good because
> pointers are often easily mishandled and cause nasty memory errors. Not
> only that but they are a difficult concept to learn in the first place.
Oddly enough, my first encounter with C was at WPI in Worcester, MA, in a
programming class in which we were taught C. Once I got used to * and &, I
honestly had no trouble with pointers. Well, understanding them. Zipping
along and hitting '&' by accident when I wanted '*' occurred and such, but
still...
> However, pointers are a useful concept with great flexibility. REBOL
> maintains that flexibility in the series! datatype while at the same
> time avoiding the problems that pointers have. It does it by
> abstracting the pointer concept through providing a reference and
> operations on the reference. This frees us as REBOL users from having
> to know about the underlying physical storage - a wonderful thing. We
> can forget about pointers too (unless you have to talk to a C DLL).
Well, since I don't have /Command, that is a moot point ;)
Still, I like to know where REBOL is, or thinks it is. I like to be able to
have some sort of index instantly available to me like that. Yes, I know, I
can use pick series 3, but when I use 'next and 'skip and whatnot.... I get
lost. And when REBOL modifies the source data when I really only wanted to
look, that irritates me to death, especially when I'm still learning such
manipulations.
> I admit that my learning about REBOL series was intially a bit hard
> too. After a while it became more natural to me. One issue for me was
> the two aspects of series: (a) they store a sequence of items (b) they
> have a current index. These two aspects allow you to think of series
> in two ways (a) the whole of a sequence (b) a position within a
> sequence. Now I find I think in terms of (a) or (b) according to what
> is more appropriate for my task. Much better than being limited to one
> way of thinking. Sometimes the words I use reflect which of the two
> aspect I'm thinking in E.g (a) Accounts, site-list (b) current-position.
I'm still going to have to work on this more. I can see very often where
REBOL is easier, particularly for new coders to learn. But it strikes me that
people who've been coding for a while in languages like C run up against brick
walls. ;) And I never ever liked using <> to mean "not equal". :P Thanks for
your help, Brett.
--Charles
