In essence, all you need is a custom string comparison routine. And the easiest, most efficient way to do that in Perl is to use the tr/// operator to 'encode' the strings and then use the standard cmp operator.

Say your custom sort rules call for 0-4 to be sorted before alphas, and 5-9 after. And within the alphas, you want upper and lower case of any given character to be sorted together. Then you set up a mapping that maps the original strings to characters that will sort in the required order.

For the given example: 

tr[0-4AaBbCcDdEeFfGgHhIiJjKkLlMmNnOoPpQqRrSsTtUuVvWwXxYyZz5-9][\x00-\x
+ff];

[download]
will do the trick. Now, you just transliterate your string and sort in the normal way:
#! perl -slw
use strict;

sub trans {
    my $in = shift;
    $in =~ tr[0-4AaBbCcDdEeFfGgHhIiJjKkLlMmNnOoPpQqRrSsTtUuVvWwXxYyZz5
+-9]
             [\x00-\xff];
    return $in;
}

chomp( my @data = <DATA> );

my @sorted = sort{
    trans( $a ) cmp trans( $b )
} @data;

print for @sorted;

__DATA__
cdef
0123456
abcd
50011
ABCD
4999
Zxyw
CDEF
zxyw
9999

[download]

Produces:

c:\test>junk78
0123456
4999
ABCD
abcd
CDEF
cdef
Zxyw
zxyw
50011
9999

[download]

Of course, you can now apply all the usual forms of sort optimisations--ST, GRT etc.--to that, but the mechanism remains the same.

The ugly head of UTF will probably complicate things a little, but, at least in the eyes of my non-UTF aware brain, it should be possible to apply the same mechanism.

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.

In reply to Re: New Alphabet Sort Order by BrowserUk
in thread New Alphabet Sort Order by Polyglot

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