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Postings from October 2016
Since 5.22.0 with the refaliasing feature, you can do, e.g.
use feature 'refaliasing';
my @a;
my ($a, $b) = 1..2;
\(@a) = \($a, $b);
print "a=(@a)\n"; # prints (1 2)
($a, $b) = 11..12;
print "a=(@a)\n"; # prints (11 12)
where the elements of @a become aliases of $a, $b. All good so far.
However, the docs don't seem to cover what happens when such an assign
expression is used in a non-void context. Also, nothing in the test
suite uses such an expression in a non-void context.
So my specific question is what should these do?
@b = (\(@a) = \($a, $b));
\(@b) = (\(@a) = \($a, $b));
(\(@a) = \($a, $b)) = \($c, $d);
my gut feeling is that they should be equivalent to
\(@a) = \($a, $b); @b = \(@a);
\(@a) = \($a, $b); \(@b) = \(@a);
\(@a) = \($a, $b); \(@a) = \($c, $d);
In the current implementation the first two cases are equivalent;
however, in the last (lval) case they differ; with this:
\(@a) = \($a, $b); \(@a) = \($c, $d);
@a[0,1] are left aliased to $c and $d, as you'd expect; with this:
(\(@a) = \($a, $b)) = \($c, $d);
@a[0,1] are left aliased to $a and $b.
--
"I do not resent criticism, even when, for the sake of emphasis,
it parts for the time with reality".
-- Winston Churchill, House of Commons, 22nd Jan 1941.
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