The postProcess<!B> function sets a process to be run before the key entered
is processed. If this function returns a value of 0, then the key injected
into the widget will not be processed; otherwise the character will be
processed as normal.  The following example demonstrates how to call the
postProcess method.
<C>$alphalistObject->postProcess ( options );

The options are defined in the following table.

Option      Default Value       Type       Purpose<!U>
Function    Required            Scalar     This is the name of the
                                           callback function.

To create a post-process callback the following code segment demonstrates
how to do it properly.

<C>$widget->postProcess ('Function' => sub { callback (@_); });

Notice that the array @_<!B> is passed into the function called
callback<!B>. This is done because when the callback process is 
called the key which was pressed is passed into the perl subroutine.
Since we nest the call-back function inside an anonymous subroutine,
we need to pass the array @_<!B> to the call-back function. If
the key given to the call-back function is a non alphanumeric key
then a predefined value will be given to the function. The following
table describes the values passed into the function.

<C><#UL><#HL(12)><#TT><#HL(15)><#UR>
<C><#VL>Key         <#VL>Key Value      <!U><#VL>
<C><#VL>Left Arrow  <#VL>KEY_LEFT       <#VL>
<C><#VL>Right Arrow <#VL>KEY_RIGHT      <#VL>
<C><#VL>Up Arrow    <#VL>KEY_UP         <#VL>
<C><#VL>Down Arrow  <#VL>KEY_DOWN       <#VL>
<C><#VL>Delete      <#VL>KEY_DELETE     <#VL>
<C><#VL>Backspace   <#VL>KEY_BACKSPACE  <#VL>
<C><#VL>Page Up     <#VL>KEY_PPAGE      <#VL>
<C><#VL>Page Down   <#VL>KEY_NPAGE      <#VL>
<C><#VL>Home        <#VL>KEY_HOME       <#VL>
<C><#VL>End         <#VL>KEY_END        <#VL>
<C><#VL>Escape      <#VL>KEY_ESC        <#VL>
<C><#LL><#HL(12)><#BT><#HL(15)><#LR>

The following code segment demonstrates how to use the post-process
method.

<F=../examples/postProcess>

<C><#HL(70)>
<C>Document Created: July,     1996
<C>Document Revised: March,    2012
