You don't need to predefine your datastructure as it will be created as you insert the data, which you could do like so 
my %tagstack;
# ... parsing code here
push @{$tagstack{requirements}}, {
    # $tag = wherever the data is coming from
    text       => $tag{cdata},
    attributes => $tag{attribs}
};

[download]
If you're just using simple nested hashes then XML::Simple may be just the module for you, and if you continue to get muddled by references and reference syntax check out the perlreftut and perlref manpages.
HTH

_________
broquaint

In reply to Re: Predefining complex data structures? by broquaint
in thread Predefining complex data structures? by Ionizor

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