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Postings from September 2005
On 9/29/05, Austin Hastings <Austin_Hastings@yahoo.com> wrote:
> Luke Palmer wrote:
> >>This is an interesting idea. Perhaps "for" (and "map") shift the
> >>minimum arity of the block from the given list and bind the maximum
> >>arity. Of course, the minimum arity has to be >= 1 lest an infinite
> >>loop occur.
> Or not. We've already seen idioms like
>>
> for (;;) ...
>
> If you specify your minimum arity as 0, then you're obviously planning to deal with it. This presumes that iterators can handle behind-the-scenes updating, of course.
Well, I see two reasons for not allowing arity zero. First, I think
it's too easy to come up with a function with minimum arity zero:
my @lengths = @list.map:&length # oops, infinite loop
Second, you don't get anything by doing this:
for @list -> *@items {
...
}
As it's equivalent to:
loop {
...
}
Where you use @list instead of @items.
Luke
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