use strict;
use warnings;

sub analyse_user_inputs {
	my $hash_ref = shift @_;
	my @the_inputs;

	foreach ( keys %{$hash_ref} ) {
		push @the_inputs, $_;
		if (ref $hash_ref->{$_} eq 'HASH') {
			push @the_inputs, @{ analyse_user_inputs($hash_ref->{$_}) };
		}
		elsif (ref $hash_ref->{$_} eq 'ARRAY') {
			foreach my $array_element (@{$hash_ref->{$_}}){
				push @the_inputs, @{ analyse_user_inputs($array_element) };
			}
		}
	}
	
	return(\@the_inputs);
}

my $data = {
	foo => 1,
	bar => [
		{
			xyzzy => 'magic',
		}
	],
	baz => {
		quux => 123,
	}
};

use Data::Dumper;
print Dumper(analyse_user_inputs($data));