I understand exactly what you're talking about - the CPAN client does something like this when installing modules and dependencies are discovered.

I did something similar when coding a simulation where mobile nodes could talk to each other either directly or by relaying through adjacent nodes if the endpoints were too far way. Essentially, if node1 could talk to node2 but not directly to node3 *AND* node2 could talk to node3, then node1 could in fact talk to node3 (by relaying through node2). If that sounds to you (like it does to me) similar to your problem, have a look at Union/Intersection of Multiple Arrays where JavaFan gave me the idea of "transitive closure" that solved my problem.

In reply to Re: Multi level dependency structure by VinsWorldcom
in thread Multi level dependency structure by MH1

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.