Perl module for multi-key sort using function results

 Data::Sorting provides functions to sort the contents of arrays based
 on a collection of extraction and comparison rules. Extraction rules
 are used to identify the attributes of array elements on which the
 ordering is based; comparison rules specify how those values should be
 ordered.
 .
 Index strings may be used to retrieve values from array elements, or
 function references may be passed in to call on each element.
 Comparison rules are provided for numeric, bytewise, and
 case-insensitive orders, as well as a 'natural' comparison that places
 numbers first, in numeric order, followed by the remaining items in
 case-insensitive textual order.