First of all, what's with all the useless parens? 

my @numbers = (2);  =>  my @numbers = 2;
my @other = (2);    =>  my @other = 2;
@numbers ~~ (2)     =>  @numbers ~~ 2
my @empty = ();     =>  my @empty;

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my @numbers = 2; @numbers ~~ 2 being false is to be expected. It was necessary to make ~~ non-commutative to fix bugs. In this case, since you're comparing against a simple scalar, a scalar comparison is made. You want 2 ~~ @numbers.

As for when (()), it should give an error if it doesn't do anything useful. I'll see about reporting a bug. ( On second thought, empty list in scalar context returns undef. I don't think anything can be done about that. )

Finally, keep in mind that when you specify an array, it's a reference to the array that's provided to the match operator. 

>perl -E"@a = qw(a b); say @a ~~ 2 ? 'match' : 'no match'"
no match

>perl -E"@a = qw(a b); say @a ~~ (0+\@a) ? 'match' : 'no match'"
match

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The idea might be to allow the following 

>perl -E"@a = qw(a b); say \@a ~~ \@a ? 'match' : 'no match'"
match

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but it actually uses a different rule. 

>perl -E"@a = qw(a b); @b = qw(a b); say \@a ~~ \@b ? 'match' : 'no ma
+tch'"
match

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This might be improvable. I'll see about bringing this up too.

In reply to Re: smart match operator should be smarter! by ikegami
in thread smart match operator should be smarter! by 7stud

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