Since @_ aliases the argument list, the following two lines are equivalent: 
my $r1 = sub { \@_ }->(@array);
my $r2 = \@array;

[download]

No they're not :-)

The first is a reference to an array that has every element aliased to every element of @array.

The second is a reference to @array.

The "trick" wouldn't work otherwise, since changing $r2 will change @array. For example.

my @array = (1..10);
my $r1 = sub { \@_ }->(@array);
pop @$r1;
print "unchanged @array\n";
my $r2 = \@array;
pop @$r2;
print "changed @array\n";

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gives us

unchanged 1 2 3 4 5 6 7 8 9 10
changed 1 2 3 4 5 6 7 8 9

[download]

In reply to Re^3: Non-destructive array processing by adrianh
in thread Non-destructive array processing by Juerd

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