This module provides a number of list utility functions, all of which take
an initial code block to control their behaviour. They are variations on
similar core perl or 'List::Util' functions of similar names, but which use
the block to control their behaviour. For example, the core Perl function
'sort' takes a list of values and returns them, sorted into order by their
string value. The 'sort_by' function sorts them according to the string
value returned by the extra function, when given each value.

my @names_sorted = sort @names;

my @people_sorted = sort_by { $_->name } @people;