That looks like a lot like the implementation of NestedLoop. Might as well use it. 

use Algorithm::Loops qw( NestedLoops );
my @digits = (1..3);
NestedLoops(
    [ (\@digits) x 4 ],
    sub { print( @_, "\n" ); },
);

[download]

Update: In addition to the above, this node originally said that BrowerUk's output was wrong and had code to fix the problem, but I was looking at a reply that produced incorrect output, not the OP. The incorrect version was removed.

In reply to Re^2: Generating lists of strings by ikegami
in thread Generating lists of strings by Anonymous Monk

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