perl 6 variable same name different sigils inconsistent behavior

Question

There seems to be some inconsistent behavior when variables of the same letter-name but different sigils are used:

> my $a="foo";
foo
> my @a=1,2
[1 2]
> say $a
foo               # this is what I have expected
> my $b = 1,2,3
(1 2 3)
> my @b = (0, $b.Slip)
[0 1]             # I expect to get [0 1 2 3]; (0, |$b) not work either
> say $b
1                 # I expect $b to be unchanged, (1,2,3), but it is now 1;
> say @a
[1 2]
> say @b
[0 1]
>

I am not sure why @a does not affect $a , whereas @b affects $b . Can someone please elucidate?

Thanks !!!

lisprog

Answer 1

In Rakudo Perl 6 there is actually no relationship at all between $b and @b .

$b didn't change. It simply didn't get assigned what you thought it had been assigned. Looking at the documentation on Operator Precedence , you'll see that = (assignment) has a tighter precedence than the comma , .

Also, you are using the REPL, which automatically prints out the return value of each statement. That return value may or may not be the same as the value assigned to a variable.

my $b = 1,2,3 actually is the same as
(my $b = 1),2,3 because = has tighter precedence than , , meaning that effectively all but the first value is ignored

> (my $b = 1),2,3
(1 2 3)
> $b
1

If you want to assign a list to $b , then put parentheses around the list:

> my $b = (1,2,3)
(1 2 3)
> $b
(1 2 3)