Re: How to tie multilevel (multidimensional) hash?

[mikezone]

Well, merlyn, I guess my lifetime's over. Regexp::Common didn't have the answer in itself, but it did provide me the clue I needed. I'm sorry to have doubted it (well, to be honest, I just didn't see it until that flash of inspiration hit me, which is to say that the FETCH() must perform a nested tie as well as the STORE()). Here's my solution (some cleanup is still to be done as testing continues, but it works!):

test.pl

#! /users/michwong/perl/bin/perl #! /users/michwong/perl/bin/perl -d:ptkdb use lib qw( . ); use MultiHash; tie %$hash, "MultiHash"; $hash->{ x }{ y } = 10; print $hash->{ x }{ y }, "\n"; $hash->{ x }{ z } = 20; print $hash->{ x }{ z }, "\n"; </code>

MultiHash.pm

package MultiHash;

sub TIEHASH {
    my ($class) = map { ref || $_ } shift;
    my $level = shift || 0;

    return bless {
        level    => $level,
        data    => {},
    }, $class;
}

sub FETCH {
    my $self = shift;
    my $key = shift;

    if( exists( $self->{ data }{ $key } )) {
        return $self->{ data }{ $key };
    } else {
        my $node = {};
        tie %$node, "MultiHash";
        $self->{ data }{ $key } = $node;
        return;
    }
}

sub STORE {
    my $self = shift;
    my $key = shift;
    my $value = shift;

    RECURSE_CASE: {
        # ===== MULTIDIMENSIONAL HASH
        if( UNIVERSAL::isa( $value, 'HASH' )) {
            if( exists $self->{ data }{ $key } ) {
                $self->{ data }{ $key } = $value;
            } else {
                my $node = {};
                tie %$node, "MultiHash";
                $self->{ data }{ $key } = $node;
            }
            last RECURSE_CASE;
        }

        if( UNIVERSAL::isa( $value, 'MultiHash' )) {
            if( exists $self->{ data }{ $key } ) {
                $self->{ data }{ $key } = $value;
            } else {
                my $node = {};
                tie %$node, "MultiHash";
                $self->{ data }{ $key } = $node;
            }
            last RECURSE_CASE;
        } 

        if( UNIVERSAL::isa( $value, 'SCALAR' )) {
            $self->{ data };
            last RECURSE_CASE;
        }
    }
    
    return $value;
}

sub DELETE {
    my $self = shift;
    my $key = shift

}

sub FIRSTKEY {
    my $self = shift;
    my $temp = keys %{ $self->{ data }};
    return scalar each %{ $self->{ data }};
}

sub NEXTKEY {
    my $self = shift;
    return scalar each %{ $self->{ data }};
}

1;