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[REBOL] Rolling your own ideal looper: does Repeat still have a bug? Re:(6)

From: lmecir:geocities at: 31-Aug-2000 8:35

> Ladislav, > > That is an impressive For function! > your example of using > >a: [1 2] > >for s a tail a 1 [print s] > as a test is very amusing bug, looks > like an infinite loop on windows, just > keeps printing newlines without ever ending. > > Just for kicks, I just tried this: > >> for s a back tail a 1 [print s] > 1 2 > 2 > > so that it stops at the last real position, > and that seemed to work, althout the expression > is more awkward and wordy! > > Your other example is this: > >> for s a next a -1 [print s] > 1 2 > > which I am not sure I get. > This would never get to next a by skipping -1. > Either you have a typo here, or I missed the point. >
Simple, For should stop immediately as for integers, because it is already behind the limit.
> If this were integers, it would look like > for x = 1 30 step -1 > > >> for s a next a 1 [print s] > 1 2 > 2 > > What is the proper behavior of > >> for s a next a -1 [print s] > ??? > > -Galt > > p.s. As far as the second-class vs. first-class values > goes, I am inclined to agree with you. There are some > fishy issues that don't seem entirely cooked. You are > right to bring them up for discussion. So far, however, > in the programs that have come up naturally in my > use of Rebol, I haven't been banging into these issues > alot. I have seen the errorhandling stuff e.g. try, disarm > seems like it's more awkward than it should be. > I could run smack into more of them at any moment, > though! > > p.p.s. I think the desire to share Rebol data and > objects across the net between two instances of rebol.exe, > or storing them and retrieving them later in native Rebol
> will come up strongly in the near future. > Even the RebMail program might be a lot simpler if > you could just save your mail objects and reload later. > Having to create extra functions for converting from > Rebol to some other disk structure and then back > again is a pain. I think Rebol can do better. > It just needs to make a few new tricks available... >
You are right with data saving - even data copying in Rebol may be an unsolvable problem.