On Fri, Aug 15, 2008 at 11:15:46PM -0700, Carl Mäsak wrote:
> r30258:
> $ ./perl6 -e '.say for [1,2,3]' # as expected
> 1
> 2
> 3
This one is actually incorrect in Rakudo -- at least according to
Pugs (and I agree with Pugs here). The correct output is "1 2 3\n".
Rakudo's output is likely incorrect for one or two reasons:
(1) Rakudo doesn't yet properly parse statement modifiers after
listops (RT #57352), and (2) I think that the C<for> statement
modifier in Rakudo is not properly placing its argument into
list context.
Until #57352 is resolved, the better test (which Rakudo also
fails at the moment, because of (2) above) is:
$ ./perl6 -e '.say() for [1,2,3]'
> $ ./perl6 -e 'for [1,2,3] { .say }' # shouldn't that be the same?
> 1 2 3
This one is correct (both Rakudo and Pugs).
> $ ./perl6 -e 'for [1,2,3] -> $a { say $a }' # or this?
> 1 2 3
This one is also correct (Rakudo and Pugs).
> $ ./perl6 -e 'for [1,2,3].list { .say }' # how do I make it...
> 1 2 3
> $ ./perl6 -e 'for @([1,2,3]) { .say }' # ...loop over the elements?
> 1 2 3
The reason that the output is "1 2 3\n" and not "1\n2\n3\n"
is that an array in list context remains a (scalar) array.
Thus the for loop is still iterating over a list of one element.
To loop over the elements it ought to be
for [1,2,3].values { .say }
Rakudo currently has this wrong also -- I suspect that it's
having trouble with the .values method on arrays.
> All in all, it's difficult to actually loop on the contents of an
> array at present. The semantics are not very consistent. I'm hoping
> this is a bug.
Yes, there are some bugs here -- several of the List methods
(.values, .keys, etc.) need some refactoring in Rakudo since it's
been decided that they're available for Any objects as well.
Pm
