Miscellany

#!/usr/bin/perl

sub cr{substr(shift, 0, -1-(shift))}
sub cl{substr(shift, (shift)+1)}
sub ip{$n=shift;$r=`factor $n`;chomp $r;$r=~s/$n: //;int($r == $n)}
sub variations{
        local $n = shift;
        local $i = 0;
        @res = ($n);
        for($i=0;$i<=(length $n)-2;$i++) {
                push @res, cr $n, $i;
                push @res, cl $n, $i;
        }
        return @res;
}
for($i=100000;$i>8;$i--) {
        @vars = variations $i;
        $error = 0;
        for($j=0;$j<=$#vars;$j++) {
                if(ip($vars[$j]) == 0) {
                        $error = 1;
                }
                last if $error;
        }
        if($error == 0) {
                print "Correct: $i\n";
                $sum += $i;
        }
}

print $sum.$/;