//
   // Description
   //    Perform substitution on the template.  We do not really recurse
   //    downward in the sense that we do not do subsitutions on inferior
   //    templates.  For each inferior template which is a part of this
   //    template, we insert the current value of their results.
   //
   // Notes
   //    Do I want to make this return a reference?
   function subst ($handle, $tag, $autoload = true) {
      $append = false;
      $debug = $this->DEBUGALL || $this->DEBUG['subst'];
      $this->LAST = $handle;

      if ($debug)
         $this->logwrite ("subst (handle=$handle, tag=$tag, autoload=$autoload)");

      // For compatibility with FastTemplate, the results need to overwrite
      // for an array.  This really only seems to be useful in the case of
      // something like
      //     $t->parse ('MAIN', array ('array', 'main'));
      // Where the 'main' template has a variable named MAIN which will be
      // set on the first pass (i.e., when parasing 'array') and used on the
      // second pass (i.e., when parsing 'main').
      if (gettype($tag) == 'array') {
         foreach (array_values($tag) as $t) {
            if ($debug)
               $this->logwrite ("subst: calling subst($handle,$t,$autoload)");
            $this->subst ($handle, $t, $autoload);
         }
         return $this->HANDLE[$handle];
      }

      // Period prefix means append result to pre-existing value.
      if (substr($tag,0,1) == '.') {
         $append = true;
         $tag = substr ($tag, 1);
         if ($debug)
            $this->logwrite ("subst (handle=$handle, tag=$tag, autoload=$autoload) in append mode");
      }
      // $this->TEMPLATE[$tag] will only be set if it was explicitly
      // declared via define(); i.e., inferior templates will not have an
      // entry.
      if (isset($this->TEMPLATE[$tag])) {
         if (!isset($this->TEMPLATE[$tag]['parsed'])
             || !$this->TEMPLATE[$tag]['parsed'])
            $this->parse_internal ($tag);
      } else {
    &