📄 classes, objects, and ties.mht

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color=3D#00ffff>;</FONT>                   <FONT color=3D#bebebe># And =
give it back
</FONT><FONT color=3D#00ffff>}</FONT><FONT color=3D#43cd80> </FONT>
<FONT color=3D#bebebe>#-----------------------------
</FONT><FONT color=3D#ffa500>sub</FONT> <FONT color=3D#b2dfee>new</FONT> =
<FONT color=3D#00ffff>{</FONT>
    <FONT color=3D#ffa500>my</FONT> <FONT =
color=3D#9ac0cd>$classname</FONT>  =3D <FONT =
color=3D#ff7f50>shift</FONT><FONT color=3D#00ffff>;</FONT>         <FONT =
color=3D#bebebe># What class are we constructing?
</FONT>    <FONT color=3D#ffa500>my</FONT> <FONT =
color=3D#9ac0cd>$self</FONT>      =3D <FONT color=3D#00ffff>{};</FONT>   =
          <FONT color=3D#bebebe># Allocate new memory
</FONT>    <FONT color=3D#98fb98>bless</FONT><FONT =
color=3D#00ffff>(</FONT>$self, $classname<FONT color=3D#00ffff>);</FONT> =
      <FONT color=3D#bebebe># Mark it of the right type
</FONT>    $self-&gt;_init<FONT color=3D#00ffff>(</FONT><FONT =
color=3D#cdad00>@_</FONT><FONT color=3D#00ffff>);</FONT>               =
<FONT color=3D#bebebe># Call _init with remaining args
</FONT>    <FONT color=3D#ffa500>return</FONT> $self<FONT =
color=3D#00ffff>;</FONT>
<FONT color=3D#00ffff>}</FONT><FONT color=3D#43cd80> </FONT>

<FONT color=3D#bebebe># "private" method to initialize fields.  It =
always sets START to
# the current time, and AGE to 0.  If called with arguments, _init
# interprets them as key+value pairs to initialize the object with.
</FONT><FONT color=3D#ffa500>sub</FONT> <FONT =
color=3D#b2dfee>_init</FONT> <FONT color=3D#00ffff>{</FONT>
    <FONT color=3D#ffa500>my</FONT> <FONT color=3D#9ac0cd>$self</FONT> =
=3D <FONT color=3D#ff7f50>shift</FONT><FONT color=3D#00ffff>;</FONT>
    $self-&gt;<FONT color=3D#00ffff>{</FONT><FONT =
color=3D#00cd00>START</FONT><FONT color=3D#00ffff>}</FONT> =3D<FONT =
color=3D#43cd80> </FONT>
<FONT color=3D#98fb98>time</FONT><FONT color=3D#00ffff>();</FONT>

    $self-&gt;<FONT color=3D#00ffff>{</FONT><FONT =
color=3D#00cd00>AGE</FONT><FONT color=3D#00ffff>}</FONT>   =3D <FONT =
color=3D#cdcd00>0</FONT><FONT color=3D#00ffff>;</FONT>
    <FONT color=3D#ffa500>if</FONT> <FONT color=3D#00ffff>(</FONT><FONT =
color=3D#cdad00>@_</FONT><FONT color=3D#00ffff>)</FONT> <FONT =
color=3D#00ffff>{</FONT>
        <FONT color=3D#ffa500>my</FONT> <FONT =
color=3D#cdcd00>%extra</FONT> =3D <FONT color=3D#cdad00>@_</FONT><FONT =
color=3D#00ffff>;</FONT>
        <FONT color=3D#9ac0cd>@$self</FONT><FONT =
color=3D#00ffff>{</FONT><FONT color=3D#ff7f50>keys</FONT> <FONT =
color=3D#cdcd00>%extra</FONT><FONT color=3D#00ffff>}</FONT> =3D <FONT =
color=3D#98fb98>values</FONT> <FONT color=3D#cdcd00>%extra</FONT><FONT =
color=3D#00ffff>;</FONT>
    <FONT color=3D#00ffff>}</FONT><FONT color=3D#43cd80> </FONT>
<FONT color=3D#00ffff>}</FONT><FONT color=3D#43cd80> </FONT>
<FONT color=3D#bebebe>#-----------------------------
</FONT></PRE></FONT></TD></TR></TBODY></TABLE></DIV>
<DIV class=3DSECT2>
<H2 class=3DSECT2><A name=3DAEN710>Destroying an Object</A></H2>
<TABLE width=3D"100%" bgColor=3D#2f4f4f border=3D0>
  <TBODY>
  <TR>
    <TD><PRE class=3DSCREEN><FONT color=3D#f5deb3 size=3D+1><FONT =
color=3D#bebebe>#-----------------------------
</FONT><FONT color=3D#ffa500>sub</FONT> <FONT =
color=3D#ff7f50>DESTROY</FONT> <FONT color=3D#00ffff>{</FONT>
    <FONT color=3D#ffa500>my</FONT> <FONT color=3D#9ac0cd>$self</FONT> =
=3D <FONT color=3D#ff7f50>shift</FONT><FONT color=3D#00ffff>;</FONT>
    <FONT color=3D#ff7f50>printf</FONT><FONT =
color=3D#00ffff>(</FONT><FONT color=3D#00cd00>"$self dying at =
</FONT><FONT color=3D#cdcd00>%s</FONT><FONT color=3D#00cd00>\n"</FONT>, =
<FONT color=3D#ff7f50>scalar</FONT> <FONT =
color=3D#98fb98>localtime</FONT><FONT color=3D#00ffff>);</FONT>
<FONT color=3D#00ffff>}</FONT><FONT color=3D#43cd80> </FONT>
<FONT color=3D#bebebe>#-----------------------------
</FONT>$self-&gt;<FONT color=3D#00ffff>{</FONT><FONT =
color=3D#00cd00>WHATEVER</FONT><FONT color=3D#00ffff>}</FONT> =3D =
$self<FONT color=3D#00ffff>;</FONT>
<FONT color=3D#bebebe>#-----------------------------
</FONT></PRE></FONT></TD></TR></TBODY></TABLE></DIV>
<DIV class=3DSECT2>
<H2 class=3DSECT2><A name=3DAEN713>Managing Instance Data</A></H2>
<TABLE width=3D"100%" bgColor=3D#2f4f4f border=3D0>
  <TBODY>
  <TR>
    <TD><PRE class=3DSCREEN><FONT color=3D#f5deb3 size=3D+1><FONT =
color=3D#bebebe>#-----------------------------
</FONT><FONT color=3D#ffa500>sub</FONT> <FONT =
color=3D#b2dfee>get_name</FONT> <FONT color=3D#00ffff>{</FONT>
    <FONT color=3D#ffa500>my</FONT> <FONT color=3D#9ac0cd>$self</FONT> =
=3D <FONT color=3D#ff7f50>shift</FONT><FONT color=3D#00ffff>;</FONT>
    <FONT color=3D#ffa500>return</FONT> $self-&gt;<FONT =
color=3D#00ffff>{</FONT><FONT color=3D#00cd00>NAME</FONT><FONT =
color=3D#00ffff>};</FONT>
<FONT color=3D#00ffff>}</FONT><FONT color=3D#43cd80> </FONT>

<FONT color=3D#ffa500>sub</FONT> <FONT color=3D#b2dfee>set_name</FONT> =
<FONT color=3D#00ffff>{</FONT>
    <FONT color=3D#ffa500>my</FONT> <FONT color=3D#9ac0cd>$self</FONT>   =
   =3D <FONT color=3D#ff7f50>shift</FONT><FONT color=3D#00ffff>;</FONT>
    $self-&gt;<FONT color=3D#00ffff>{</FONT><FONT =
color=3D#00cd00>NAME</FONT><FONT color=3D#00ffff>}</FONT> =3D <FONT =
color=3D#ff7f50>shift</FONT><FONT color=3D#00ffff>;</FONT>
<FONT color=3D#00ffff>}</FONT><FONT color=3D#43cd80> </FONT>
<FONT color=3D#bebebe>#-----------------------------
</FONT><FONT color=3D#ffa500>sub</FONT> <FONT =
color=3D#b2dfee>name</FONT> <FONT color=3D#00ffff>{</FONT>
    <FONT color=3D#ffa500>my</FONT> <FONT color=3D#9ac0cd>$self</FONT> =
=3D <FONT color=3D#ff7f50>shift</FONT><FONT color=3D#00ffff>;</FONT>
    <FONT color=3D#ffa500>if</FONT> <FONT color=3D#00ffff>(</FONT><FONT =
color=3D#cdad00>@_</FONT><FONT color=3D#00ffff>)</FONT> <FONT =
color=3D#00ffff>{</FONT> $self-&gt;<FONT color=3D#00ffff>{</FONT><FONT =
color=3D#00cd00>NAME</FONT><FONT color=3D#00ffff>}</FONT> =3D <FONT =
color=3D#ff7f50>shift</FONT> <FONT color=3D#00ffff>}</FONT><FONT =
color=3D#43cd80> </FONT>
    <FONT color=3D#ffa500>return</FONT> $self-&gt;<FONT =
color=3D#00ffff>{</FONT><FONT color=3D#00cd00>NAME</FONT><FONT =
color=3D#00ffff>};</FONT>
<FONT color=3D#00ffff>}</FONT><FONT color=3D#43cd80> </FONT>
<FONT color=3D#bebebe>#-----------------------------
</FONT><FONT color=3D#ffa500>sub</FONT> <FONT color=3D#b2dfee>age</FONT> =
<FONT color=3D#00ffff>{</FONT>
    <FONT color=3D#ffa500>my</FONT> <FONT color=3D#9ac0cd>$self</FONT> =
=3D <FONT color=3D#ff7f50>shift</FONT><FONT color=3D#00ffff>;</FONT>
    <FONT color=3D#ffa500>my</FONT> <FONT color=3D#9ac0cd>$prev</FONT> =
=3D $self-&gt;<FONT color=3D#00ffff>{</FONT><FONT =
color=3D#00cd00>AGE</FONT><FONT color=3D#00ffff>};</FONT>
    <FONT color=3D#ffa500>if</FONT> <FONT color=3D#00ffff>(</FONT><FONT =
color=3D#cdad00>@_</FONT><FONT color=3D#00ffff>)</FONT> <FONT =
color=3D#00ffff>{</FONT> $self-&gt;<FONT color=3D#00ffff>{</FONT><FONT =
color=3D#00cd00>AGE</FONT><FONT color=3D#00ffff>}</FONT> =3D <FONT =
color=3D#ff7f50>shift</FONT> <FONT color=3D#00ffff>}</FONT><FONT =
color=3D#43cd80> </FONT>
    <FONT color=3D#ffa500>return</FONT> $prev<FONT =
color=3D#00ffff>;</FONT>
<FONT color=3D#00ffff>}</FONT><FONT color=3D#43cd80> </FONT>
<FONT color=3D#bebebe># sample call of get and set: happy birthday!
</FONT>$obj-&gt;age<FONT color=3D#00ffff>(</FONT> <FONT =
color=3D#cdcd00>1</FONT> + $obj-&gt;age <FONT color=3D#00ffff>);</FONT>
<FONT color=3D#bebebe>#-----------------------------
</FONT>$him =3D Person-&gt;
new<FONT color=3D#00ffff>()</FONT>
<FONT color=3D#00ffff>;</FONT>
$him-&gt;<FONT color=3D#00ffff>{</FONT><FONT =
color=3D#00cd00>NAME</FONT><FONT color=3D#00ffff>}</FONT> =3D <FONT =
color=3D#00cd00>"Sylvester"</FONT><FONT color=3D#00ffff>;</FONT>
$him-&gt;<FONT color=3D#00ffff>{</FONT><FONT =
color=3D#00cd00>AGE</FONT><FONT color=3D#00ffff>}</FONT>  =3D <FONT =
color=3D#cdcd00>23</FONT><FONT color=3D#00ffff>;</FONT>
<FONT color=3D#bebebe>#-----------------------------
</FONT><FONT color=3D#ffa500>use</FONT> <FONT =
color=3D#b2dfee>Carp</FONT><FONT color=3D#00ffff>;</FONT>
<FONT color=3D#ffa500>sub</FONT> <FONT color=3D#b2dfee>name</FONT> <FONT =
color=3D#00ffff>{</FONT>
    <FONT color=3D#ffa500>my</FONT> <FONT color=3D#9ac0cd>$self</FONT> =
=3D <FONT color=3D#ff7f50>shift</FONT><FONT color=3D#00ffff>;</FONT>
    <FONT color=3D#ffa500>return</FONT> $self-&gt;<FONT =
color=3D#00ffff>{</FONT><FONT color=3D#00cd00>NAME</FONT><FONT =
color=3D#00ffff>}</FONT> <FONT color=3D#ffa500>unless</FONT> <FONT =
color=3D#cdad00>@_</FONT><FONT color=3D#00ffff>;</FONT>
    <FONT color=3D#ffa500>local</FONT> <FONT color=3D#9ac0cd>$_</FONT> =
=3D <FONT color=3D#ff7f50>shift</FONT><FONT color=3D#00ffff>;</FONT>
    croak <FONT color=3D#00cd00>"too many arguments"</FONT> <FONT =
color=3D#ffa500>if</FONT> <FONT color=3D#cdad00>@_</FONT><FONT =
color=3D#00ffff>;</FONT>
    <FONT color=3D#ffa500>if</FONT> <FONT =
color=3D#00ffff>(</FONT>$^W<FONT color=3D#00ffff>)</FONT> <FONT =
color=3D#00ffff>{</FONT>
        /<FONT color=3D#00ffff>[</FONT>^\s\w<FONT color=3D#00cd00>'-]/   =
      &amp;&amp; carp "funny characters in name"; #'</FONT>
        /\d/                &amp;&amp; carp <FONT =
color=3D#00cd00>"numbers in name"</FONT><FONT color=3D#00ffff>;</FONT>
        /\S+<FONT color=3D#00ffff>(</FONT>\s+\S+<FONT =
color=3D#00ffff>)</FONT>+/      || carp <FONT color=3D#00cd00>"prefer =
multiword name"</FONT><FONT color=3D#00ffff>;</FONT>
        /\S/                || carp <FONT color=3D#00cd00>"name is =
blank"</FONT><FONT color=3D#00ffff>;</FONT>
    <FONT color=3D#00ffff>}</FONT><FONT color=3D#43cd80> </FONT>
    <FONT color=3D#ff7f50>s</FONT>/<FONT =
color=3D#00ffff>(</FONT>\w+<FONT color=3D#00ffff>)</FONT>/\u\L$<FONT =
color=3D#cdcd00>1</FONT>/g<FONT color=3D#00ffff>;</FONT>       <FONT =
color=3D#bebebe># enforce capitalization
</FONT>    $self-&gt;<FONT color=3D#00ffff>{</FONT><FONT =
color=3D#00cd00>NAME</FONT><FONT color=3D#00ffff>}</FONT> =3D $_<FONT =
color=3D#00ffff>;</FONT>
<FONT color=3D#00ffff>}</FONT><FONT color=3D#43cd80> </FONT>
<FONT color=3D#bebebe>#-----------------------------
</FONT><FONT color=3D#ffa500>package</FONT> <FONT =
color=3D#b2dfee>Person</FONT><FONT color=3D#00ffff>;</FONT>

<FONT color=3D#bebebe># this is the same as before...
</FONT><FONT color=3D#ffa500>sub</FONT> <FONT color=3D#b2dfee>new</FONT> =
<FONT color=3D#00ffff>{</FONT>
     <FONT color=3D#ffa500>my</FONT> <FONT color=3D#9ac0cd>$that</FONT>  =
=3D <FONT color=3D#ff7f50>shift</FONT><FONT color=3D#00ffff>;</FONT>
     <FONT color=3D#ffa500>my</FONT> <FONT color=3D#9ac0cd>$class</FONT> =
=3D <FONT color=3D#98fb98>ref</FONT><FONT =
color=3D#00ffff>(</FONT>$that<FONT color=3D#00ffff>)</FONT> || =
$that<FONT color=3D#00ffff>;</FONT>
     <FONT color=3D#ffa500>my</FONT> <FONT color=3D#9ac0cd>$self</FONT> =
=3D <FONT color=3D#00ffff>{</FONT>
           <FONT color=3D#00cd00>NAME</FONT>  =3D&gt; <FONT =
color=3D#ff7f50>undef</FONT>,
           <FONT color=3D#00cd00>AGE</FONT>   =3D&gt; <FONT =
color=3D#ff7f50>undef</FONT>,
           <FONT color=3D#00cd00>PEERS</FONT> =3D&gt; <FONT =
color=3D#00ffff>[]</FONT>,
    <FONT color=3D#00ffff>};</FONT>
    <FONT color=3D#98fb98>bless</FONT><FONT =
color=3D#00ffff>(</FONT>$self, $class<FONT color=3D#00ffff>);</FONT>
    <FONT color=3D#ffa500>return</FONT> $self<FONT =
color=3D#00ffff>;</FONT>
<FONT color=3D#00ffff>}</FONT>

<FONT color=3D#ffa500>use</FONT> <FONT color=3D#b2dfee>Alias</FONT> =
<FONT color=3D#ff7f50>qw</FONT><FONT color=3D#00ffff>(</FONT>attr<FONT =
color=3D#00ffff>);</FONT>
<FONT color=3D#ffa500>use</FONT> <FONT color=3D#b2dfee>vars</FONT> <FONT =
color=3D#ff7f50>qw</FONT><FONT color=3D#00ffff>(</FONT>$NAME $AGE <FONT =
color=3D#cdad00>@PEERS</FONT><FONT color=3D#00ffff>);</FONT>

<FONT color=3D#ffa500>sub</FONT> <FONT color=3D#b2dfee>name</FONT> <FONT =
color=3D#00ffff>{</FONT>
    <FONT color=3D#ffa500>my</FONT> <FONT color=3D#9ac0cd>$self</FONT> =
=3D attr <FONT color=3D#ff7f50>shift</FONT><FONT =
color=3D#00ffff>;</FONT>
    <FONT color=3D#ffa500>if</FONT> <FONT color=3D#00ffff>(</FONT><FONT =
color=3D#cdad00>@_</FONT><FONT color=3D#00ffff>)</FONT> <FONT =
color=3D#00ffff>{</FONT> $NAME =3D <FONT =
color=3D#ff7f50>shift</FONT><FONT color=3D#00ffff>;</FONT> <FONT =
color=3D#00ffff>}</FONT>
    <FONT color=3D#ffa500>return</FONT>    $NAME<FONT =
color=3D#00ffff>;</FONT>
<FONT color=3D#00ffff>};</FONT>

<FONT color=3D#ffa500>sub</FONT> <FONT color=3D#b2dfee>age</FONT> <FONT =
color=3D#00ffff>{</FONT>
    <FONT color=3D#ffa500>my</FONT> <FONT color=3D#9ac0cd>$self</FONT> =
=3D attr <FONT color=3D#ff7f50>shift</FONT><FONT =
color=3D#00ffff>;</FONT>
    <FONT color=3D#ffa500>if</FONT> <FONT color=3D#00ffff>(</FONT><FONT =
color=3D#cdad00>@_</FONT><FONT color=3D#00ffff>)</FONT> <FONT =
color=3D#00ffff>{</FONT> $AGE =3D <FONT =
color=3D#ff7f50>shift</FONT><FONT color=3D#00ffff>;</FONT> <FONT =
color=3D#00ffff>}</FONT>
    <FONT color=3D#ffa500>return</FONT>    $AGE<FONT =
color=3D#00ffff>;</FONT>
<FONT color=3D#00ffff>}</FONT>

<FONT color=3D#ffa500>sub</FONT> <FONT color=3D#b2dfee>peers</FONT> =
<FONT color=3D#00ffff>{</FONT>
    <FONT color=3D#ffa500>my</FONT> <FONT color=3D#9ac0cd>$self</FONT> =
=3D attr <FONT color=3D#ff7f50>shift</FONT><FONT =
color=3D#00ffff>;</FONT>
    <FONT color=3D#ffa500>if</FONT> <FONT color=3D#00ffff>(</FONT><FONT =
color=3D#cdad00>@_</FONT><FONT color=3D#00ffff>)</FONT> <FONT =
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