In perl, a tie on arrays works by creating a temporary proxy object when you do an array subscript. When you later try to read or write to this object, it triggers the call to FETCH or STORE as appropriate. It is necessary to do it like that to allow code like this to Do The Right Thing: 
sub p1 { print $_[0]} p1($tied_array[0]); # calls FETCH
sub p2 { $_[0] = 0 }  p2($tied_array[0]); # calls STORE

[download]
The net affect of this is that weaken($b[0]) is actually trying to weaken the temporary proxy object rather then the stored reference. (At least that's what I'm speculating; I've got a cold and it's too much effort to check right now)

Dave.

In reply to Re: Bug with weaken vs tie ??? by dave_the_m
in thread Bug with weaken vs tie ??? by nothing94

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.