#figure this out later#my $separator_characters=" _-\\\\\\\.";      # these are the separator characters ready for use in a regex
sub __natural_split_item($)
{
    my @out_array;
    #
    # by brute force we will separate a string into the output array
    # by these cases as they are found:
    #
    # separator characters
    # numerics
    # alpha/non numeric
    #
    # we may need to add other stuff in the future...
    #
    # when we change to a different type we will push the previous data into
    # the output array.
    #
    my $last_type=0;      # set to no previous
    my $last_split="";
    if(defined $_[0])        # we may get an undefined item....
    {
        for(my $i=0;$i<length $_[0];$i++)
        {
            my $thischar=substr $_[0],$i,1;         # will need to do something for unicode if we need it....
            my $thistype;    # just do not use zero and do not duplicate values.
            #
            # separator characters may need to be handled a little differently.
            # first, we need to change them into spaces and second we need to
            # push them on the output array as single characters.  this may fix
            # the __ versus _ sort cases where __ shows up first but we do the _
            # first.
            #
            # note that the number selected for $thistype does not matter - we are
            # only looking for a change in separator type.
            #
            #figure this out later#if($thischar =~ /[$separator_characters]/)                      # this character is a separator character
            if($thischar =~ /[ _\\\.]/)                      # this character is a separator character
            {
                $thistype=100;
                $thistype++ if($last_type == $thistype);                  # repeated separators of any sort must be treated a bit differently
                $thischar=" ";
            }
            elsif($thischar =~ /^\d$/) { $thistype=200; }                 # this character is a numeric character
            else { $thistype=300; }                                       # this character is a non numeric

            if($last_type!=0         # if we have a previous type (0 means no previous)
            && $last_type!=$thistype #    and we have changed type
            && $last_split ne ""     #    and we have something to push (we should if we get to this test)
              )
            {
                push @out_array,$last_split;
                $last_split="";
            }
            $last_type=$thistype;
            $last_split .= $thischar;    # add this character to the current
        }
        push @out_array,$last_split;      # add the last component
    }
    return @out_array;
}

sub my_custom_natural_sort
{
    my @a_list=__natural_split_item $a;
    my @b_list=__natural_split_item $b;
    for (my $i=0;defined $a_list[$i] && defined $b_list[$i];$i++)
    {
        next if $a_list[$i] eq $b_list[$i];      # move on to next item if this split component is the same
        if(($a_list[$i]=~ /\d\d*/) && ($b_list[$i]=~ /\d\d*/))   # if both numeric to a numeric test first
        {
            return $a_list[$i] <=> $b_list[$i] if $a_list[$i] != $b_list[$i];    # simple numeric compare if not same value
            return $a_list[$i] cmp $b_list[$i] if $a_list[$i] ne $b_list[$i];    # ascii compare so we can handle leading zero variationsif not same value
        }
        return (lc $a_list[$i]) cmp (lc $b_list[$i]) if (lc $a_list[$i]) ne (lc $b_list[$i]);    # compare as same case first
        #return ($a_list[$i]) cmp ($b_list[$i]) if ($a_list[$i]) ne ($b_list[$i]);                # then compare as case sensitive (maybe)
    }
    return (length @a_list) <=> (length @b_list);    # just do list length - longer list should be later.  if items the same then it does not matter....
}