PHP/Reflection/interface exists

_exists function

   <source lang="html4strict">

bool function_exists (string function_name) bool method_exists (object object, string method_name) bool class_exists (string class_name [, bool autoload]) bool interface_exists (string interface_name [, bool autoload]) <?php

 if (function_exists($isemail)){
   if (isemail($email)){
   } else {
     echo "Not a valid e-mail address.";
   }
 } else {
   echo "Function does not exist.
";
 }
 
 if (class_exists (myparent)){
   class anyclass extends myparent {
     public $somemember;
     public function dosomething (){
       if (method_exists (parent,"parentmethod")){
       } else {
       }
     }
   }
 } else {
   echo "Class does not exist.
";
 }
 if (isset ($_POST["searchterm"])){
 } else {
   echo "You must submit a search term.  Please press the Back button.";
 }

?>

 </source>