On 8/17/06, Jonathan Scott Duff <[EMAIL PROTECTED]> wrote:
Depends on when it fires I guess. Your example might be equivalent to
this perl5ish:

    while (1) {
        $num = rand;
        print $num;
        last if $num < 0.9;
        print ",";              # NEXT
    print "\n";                 # LAST

Which, incidentally, relates back to the discussion at hand.  If this
were the case, though, the state of the variables (in three-arg for
loops and side-effecty while loops) would seem to reflect the state of
the next iteration from the rest of the code.  It would also
(obviously) fire after user input for eg. a for =<> loop.

So, unless the next paragraph is feasible, I think NEXT ought to be
equivalent to LEAVE, perhaps with the exception of exceptional

But I was talking about hypotheticalization.  That is, unless I am
mistaken we have temp {} and let {} using UNDO blocks (which are given
default definitions where possible).  So perhaps we could use that
feature to provide a NEXT trait which actually executes only if there
is a next iteration, while giving the block the impression that it is
executing in the previous iteration.  This, of course, would not work
for loops whose conditions have irreversible side-effects.

Overall, it might be feasible in some circumstances, but it may not be
worth it.  Its implementation (and usage caveats) are quite complex
for a relatively minor convenience feature.  For a user to implement
its effect by himself, using the extended knowledge he has of the loop
semantics, would probably not take more than four extra lines in the
worst case.


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