Registers a PHP file containing OPT instruction sources. They will be loaded only, if the compiler needs it. Use this method in connection with optClass::registerInstruction():

<?php
  $tpl -> registerInstructionFile('myInstructions.php');
  // Register instructions located in the file above
  $tpl -> registerInstruction('optInstruction1');
  $tpl -> registerInstruction('optInstruction2');
?>

Note: this method is not available, if the Register method family was removed from the source with OPT Configurator.