I'd never create a sub for that.

%h = (
 pizza   => { foo => 14, bar => 29 },
 shoarma => { foo =>  2, bar => 53 },
 gyros   => { foo => 10, bar => 35 },
);

@keys_sorted_foo_ascn = sort { $h{$a}{foo} <=> $h{$b}{foo} } keys %h;
@keys_sorted_foo_desc = sort { $h{$b}{foo} <=> $h{$a}{foo} } keys %h;
@keys_sorted_bar_ascn = sort { $h{$a}{bar} <=> $h{$b}{bar} } keys %h;
@keys_sorted_bar_desc = sort { $h{$b}{bar} <=> $h{$a}{bar} } keys %h;
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I find this a LOT easier than using a sub.

2;0 juerd@ouranos:~$ perl -e'undef christmas'
Segmentation fault
2;139 juerd@ouranos:~$
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