mingw/html/lib/Tie/RefHash.html

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  13 <big><strong><span class="block">&nbsp;Tie::RefHash - use references as hash keys</span></strong></big>
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  20 <ul>
  21
  22         <li><a href="#name">NAME</a></li>
  23         <li><a href="#synopsis">SYNOPSIS</a></li>
  24         <li><a href="#description">DESCRIPTION</a></li>
  25         <li><a href="#example">EXAMPLE</a></li>
  26         <li><a href="#author">AUTHOR</a></li>
  27         <li><a href="#version">VERSION</a></li>
  28         <li><a href="#see_also">SEE ALSO</a></li>
  29 </ul>
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  31
  32 <hr />
  33 <p>
  34 </p>
  35 <h1><a name="name">NAME</a></h1>
  36 <p>Tie::RefHash - use references as hash keys</p>
  37 <p>
  38 </p>
  39 <hr />
  40 <h1><a name="synopsis">SYNOPSIS</a></h1>
  41 <pre>
  42     require 5.004;
  43     use Tie::RefHash;
  44     tie HASHVARIABLE, 'Tie::RefHash', LIST;
  45     tie HASHVARIABLE, 'Tie::RefHash::Nestable', LIST;</pre>
  46 <pre>
  47     untie HASHVARIABLE;</pre>
  48 <p>
  49 </p>
  50 <hr />
  51 <h1><a name="description">DESCRIPTION</a></h1>
  52 <p>This module provides the ability to use references as hash keys if you
  53 first <code>tie</code> the hash variable to this module.  Normally, only the
  54 keys of the tied hash itself are preserved as references; to use
  55 references as keys in hashes-of-hashes, use Tie::RefHash::Nestable,
  56 included as part of Tie::RefHash.</p>
  57 <p>It is implemented using the standard perl TIEHASH interface.  Please
  58 see the <code>tie</code> entry in <code>perlfunc(1)</code> and <code>perltie(1)</code> for more information.</p>
  59 <p>The Nestable version works by looking for hash references being stored
  60 and converting them to tied hashes so that they too can have
  61 references as keys.  This will happen without warning whenever you
  62 store a reference to one of your own hashes in the tied hash.</p>
  63 <p>
  64 </p>
  65 <hr />
  66 <h1><a name="example">EXAMPLE</a></h1>
  67 <pre>
  68     use Tie::RefHash;
  69     tie %h, 'Tie::RefHash';
  70     $a = [];
  71     $b = {};
  72     $c = \*main;
  73     $d = \&quot;gunk&quot;;
  74     $e = sub { 'foo' };
  75     %h = ($a =&gt; 1, $b =&gt; 2, $c =&gt; 3, $d =&gt; 4, $e =&gt; 5);
  76     $a-&gt;[0] = 'foo';
  77     $b-&gt;{foo} = 'bar';
  78     for (keys %h) {
  79        print ref($_), &quot;\n&quot;;
  80     }</pre>
  81 <pre>
  82     tie %h, 'Tie::RefHash::Nestable';
  83     $h{$a}-&gt;{$b} = 1;
  84     for (keys %h, keys %{$h{$a}}) {
  85        print ref($_), &quot;\n&quot;;
  86     }</pre>
  87 <p>
  88 </p>
  89 <hr />
  90 <h1><a name="author">AUTHOR</a></h1>
  91 <p>Gurusamy Sarathy        <a href="mailto:gsar@activestate.com">gsar@activestate.com</a></p>
  92 <p>'Nestable' by Ed Avis   <a href="mailto:ed@membled.com">ed@membled.com</a></p>
  93 <p>
  94 </p>
  95 <hr />
  96 <h1><a name="version">VERSION</a></h1>
  97 <p>Version 1.32</p>
  98 <p>
  99 </p>
 100 <hr />
 101 <h1><a name="see_also">SEE ALSO</a></h1>
 102 <p>perl(1), perlfunc(1), <code>perltie(1)</code></p>
 103 <table border="0" width="100%" cellspacing="0" cellpadding="3">
 104 <tr><td class="block" style="background-color: #cccccc" valign="middle">
 105 <big><strong><span class="block">&nbsp;Tie::RefHash - use references as hash keys</span></strong></big>
 106 </td></tr>
 107 </table>
 108
 109 </body>
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