#! /usr/bin/perl
use strict;
use warnings;
use Benchmark qw( cmpthese );
use List::Util qw( shuffle );

my @unsorted = 
  shuffle
    map { { $_ => [] }  }
    'aaa' .. 'bbb';

warn "Testing with ", scalar(@unsorted), " values.\n";


cmpthese( -1, {

    direct => \&direct_sort,
    ST     => \&schwartzian,
    
});


sub direct_sort {
    
    return sort {
        (keys %$a)[0] cmp (keys %$b)[0]
    } @unsorted;
}

sub schwartzian {
    return map { $_->[0] }
      sort { $a->[1] cmp $b->[1] }
        map { [ $_, keys %$_ ] }
          @unsorted;    
}