public static function isFunction($function_name) {
    $function_names = func_get_args();

    return function ($node) use ($function_names) {
      if ($node instanceof FunctionDeclarationNode) {
        return in_array($node->getName()->getText(), $function_names, TRUE);
      }
      return FALSE;
    };
  }
public static function isFunction($function_name) {
    $function_names = func_get_args();

    return function ($node) use ($function_names) {
      if ($node instanceof FunctionDeclarationNode) {
        return in_array($node->getName()->getText(), $function_names, TRUE);
      }
      return FALSE;
    };
  }
public static function isFunction ( $ function_name ) { $ function_names = func_get_args ( ) ; return function ( $ node ) use ( $ function_names ) { if ( $ node instanceof FunctionDeclarationNode ) { return in_array ( $ node -> getName ( ) -> getText ( ) , $ function_names , TRUE ) ; } return FALSE ; } ; }
Callback to filter for specific function declaration.

@param string $function_name ...
At least one function name to search for.

@return callable
Callback to filter for specific function declaration .