As a "i just now made this up rule of thumb", use braces when parens won't do. Parens are just a fragile container for lists, they will flatten by default: 

my @one_d = ( (1,2,3), (4,5,6), (7,8,9) );

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is really just a single list. You have to use braces: 
my @two_d = ( [1,2,3], [4,5,6], [7,8,9] );

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I prefer to use a reference to an anonymous array for the outside container, maily because there is no mixing of parens and braces, square or curly: 
my $two_d = [ [1,2,3], [4,5,6], [7,8,9] ];

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When in doubt, always consult Data::Dumper. Always! If you had used Data::Dumper on your data structure, you would have seen that the problem was within it: 
print Dumper \@AoH;

__END__
(it's an AoHoH ... not an AoHoAoH)
$VAR1 = [
          {
            'page' => {
                        'paragraph' => 'lesson1'
                      },
            'chapter' => 'Basic',
            'HASH(0x8638dec)' => undef
          },
          {
            'HASH(0x86fee04)' => undef,
            'page' => {
                        'paragraph' => 'lesson3'
                      },
            'chapter' => 'Advanced'
          }
        ];

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Finally, print out a copy of References quick reference. And don't forget about Data::Dumper! :)

jeffa

L-LL-L--L-LL-L--L-LL-L--
-R--R-RR-R--R-RR-R--R-RR
B--B--B--B--B--B--B--B--
H---H---H---H---H---H---
(the triplet paradiddle with high-hat)

In reply to Re^3: Accessing an AoHoAoH by jeffa
in thread Accessing an AoHoAoH by bradcathey

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