$_ = "#x";
my @a = qw/b c/;

foo /#(\w+)/, @a;
bar /#(\w+)/, @a;
quz /#(\w+)/, @a;
baz /#(\w+)/, @a;

##</code><code>##

sub foo       { print Dumper(\@_) }
sub bar ()    { print Dumper(\@_) }
sub quz ($)   { print Dumper(\@_) }
sub baz ($\@) { print Dumper(\@_) }

##</code><code>##

foo( /#(\w+)/, @a );
(  bar() /  # division; "#(\w+)/, @a;" is a comment
   quz( /#(\w+)/ )
), @a;  # void context
&baz( scalar(/#(\w+)/), \@a );

##</code><code>##

$VAR1 = ['x','b','c'];   # sub foo
$VAR1 = [];              # sub bar ()
$VAR1 = [1];             # sub quz ($)
$VAR1 = [1, ['b','c']];  # sub baz ($\@)