On IRC I said this was a bug, because the behaviour seemed so surprising, but
now that I made a fix for it (diff attached), I find breakage in
t/spec/S03-metaops/zip.t and t/spec/S32-container/roundrobin.t that test for
what I see is a contradictory (to this ticket) behaviour for RT#126522.
Basically roundrobin, zip, and a few others aren't meant to treat itemized
lists as lists and instead treat them as a single item. This is why the
behaviour in this ticket is observed: array's elements are itemized and so get
treated differently.
So.... this is just a pitfall of sorts and isn't a bug?
diff --git a/src/core/List.pm b/src/core/List.pm
index 4edd254..172009b 100644
--- a/src/core/List.pm
+++ b/src/core/List.pm
@@ -1593,14 +1593,14 @@ multi sub infix:<Z>(+lol) {
return Seq.new(Rakudo::Internals.EmptyIterator) if $arity == 0;
eager my @l = (^$arity).map: -> $i {
my \elem = lol[$i];
- if nqp::iscont(elem) {
- $laze = False;
- Rakudo::Internals.WhateverIterator((elem,))
- }
- else {
+ if nqp::istype(elem, Iterable) {
$laze = False unless elem.is-lazy;
Rakudo::Internals.WhateverIterator(elem)
}
+ else {
+ $laze = False;
+ Rakudo::Internals.WhateverIterator((elem,))
+ }
}
gather {
@@ -1622,13 +1622,13 @@ my &zip := &infix:<Z>;
sub roundrobin(**@lol is raw) {
my $laze = False;
my @iters = do for @lol -> \elem {
- if nqp::iscont(elem) {
- (elem,).iterator
- }
- else {
+ if nqp::istype(elem, Iterable) {
$laze = True if elem.is-lazy;
elem.iterator
}
+ else {
+ (elem,).iterator
+ }
}
gather {
while @iters {
