sub rekey {
	my $h = shift;
	KEY: for my $k (keys %$h) {
		if (ref $$h{$k} eq 'ARRAY') {
			rekey($_) for @{$$h{$k}};
			my %n;
			for my $e (@{$$h{$k}}) {
				next KEY unless exists $$e{name};
				die "duplicate key '$$e{name}'"
					if exists $n{$$e{name}};
				$n{$$e{name}} = $e;
			}
			$$h{$k} = \%n;
		}
		elsif (ref $$h{$k} eq 'HASH')
			{ rekey($$h{$k}) }
	}
}
rekey( $foo );