I'm not sure why you're using a hash there when this should do the trick: 
sub safeswitch
{
        no strict 'refs';
        my @P = map { $$_ } 0..@+;
        $_[0] =~ s/\$(\d+)/$P[$1]/g;
        $_[0];
}

[download]
As far as I can tell, you're only using %seen to count?

In reply to Re: $1 in variable regex replacement string by tadman
in thread $1 in variable regex replacement string by dvergin

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