Actually modules on CPAN that work with PDF are able to parse deeper than just document info.

PDF GetInfo( has discussion that may be of interest to you.

Also, answer to your question depends on whether you want just parse PDF using pure perl, or may be use Adobe Acrobat via Win32::OLE and then sending miscellaneous commands to it.

And finally, two words from my own experience on this:
all those streams inside PDF file could be easily extracted and converted into text via Compress::Zlib perl module without problems. I am not sure it is helpfull, but 100% possible.

Courage, the Cowardly Dog.