use strict;
use warnings;

my @list = qw( R1-U10 R1-U1 R10-U11
R10-U1
R2-U2
R3-U13
R10-U5
R2
);

@list = sort special_compare @list;

print "$_\n" for @list;

sub special_compare
{
    my (@myA) = $a =~ /([a-zA-z_]+|\d+)/g;
    my (@myB) = $b =~ /([a-zA-z_]+|\d+)/g;
    
    my $result=0;
    
    my $Atoken;
    my $Btoken;
    
    while ( defined ($Atoken = shift @myA) and defined ($Btoken = shift @myB)
           and $result == 0)
    {
        my $numeric = 0;
        $numeric = 1 if ($Atoken =~ /\d/ and $Btoken =~ /\d/);
        
        if ($numeric)
        {
            $result = ($Atoken <=> $Btoken);
        }
        else
        {
            $result = ($Atoken cmp $Btoken);
        }
    }
    
    if ($result ==0) #if one array "runs out", longest is "greater"
    {
        return -1 if (@myA < @myB);
        return 1  if (@myA > @myB);
    }
    return $result;    
}

__END__
R1-U1
R1-U10
R2
R2-U2
R3-U13
R10-U1
R10-U5
R10-U11

##</code><code>##

Prototype: R10-U1
Fields: A1 N2 A3 N4
Sort Order: A3 N4 A1 N2

##</code><code>##

use strict;
use warnings;

my @list = qw( R1U1
R2U3
R10U1
R10-U1
R2-U2
R3-U13
R10-U5
R2
);

@list = sort special_compare @list;

print "$_\n" for @list;

sub special_compare
{
    my (@myA) = $a =~ /([a-zA-z_]+|\d+)/g;
    my (@myB) = $b =~ /([a-zA-z_]+|\d+)/g;
    
    my $result=0;
    
    my $Atoken;
    my $Btoken;
    
    while ( defined ($Atoken = shift @myA) and defined ($Btoken = shift @myB)
           and $result == 0)
    {   
       $result = ($Atoken cmp $Btoken);     
    }
    
    if ($result ==0) #if one array "runs out", longest is "greater"
    {
        return -1 if (@myA < @myB);
        return 1  if (@myA > @myB);
    }
    return $result;    
}

__END__
R1U1
R10U1
R10-U1
R10-U5
R2
R2-U2
R2U3
R3-U13