use strict;
use warnings;
use Data::Rmap qw(:all);

my @AoH = (
	{'name' => 'Barney', 'age' => '34'},
	{'name' => 'Fred', 'age' => '36'},
	{'name' => { first => 'John', last => 'Doe' }, age => '40' }
);

rmap_hash {
	print join "\n" => keys %$_;
	print "\n";
} @AoH;