(tye)Re3: The Definitive Unit Conversion Script

[tye]

This doesn't have to be complicated. Split on * and before /, then check for /\^\d+$/:

    my @units= split m#(?<=.)(?:(?=/)|\*)#, $units, -1;
    my %power;
    for my $unit (  @units  ) {
        my $power= 1;
        if(  $unit =~ s#\^(\d+)$##  ) {
            $power= $1;
        }
        if(  $unit =~ s#^/##  ) {
            $power= -$power;
        }
        $power{$unit} += $power;
    }
    # ...

then you have to find units that you can convert to with matching powers. So, if you start with kg/cm/sec [ which becomes (kg=>1,cm=>-1,sec=>-1) ] and are asked to return lb/ft/hr (lb=>1,ft=>-1,hr=>-1), then you have to convert from kg to lb, then convert cm to either ft or hr (there will be no cm-to-hr path so you'll do cm-to-ft), then convert the left-overs, sec-to-hr. And you're done.

(Updated and tested.)

        - tye