Method is

basex-core/src/main/java/org/basex/query/func/AFunction.java:35–35

Checks if the specified expression is an instance of this function. @param ex expression @return result of check

(final Expr ex)

   * @return result of check
   */
  default boolean is(final Expr ex) {
    return ex instanceof final StandardFunc sf && sf.definition == definition();
  }