Section 10.5.5, A.8.2
Subroutine calls without parens

In 10.5.5, REPLACE

When a task or function specifies no arguments, the empty parenthesis, (), following the task/function name shall be optional. This is also true for tasks or functions that require arguments, when all arguments have defaults specified.

WITH

When a task or method specifies no arguments, the empty parenthesis, (), following the subroutine name shall be optional. This is also true for tasks or methods that require arguments, when all arguments have defaults specified.

In A.8.2, REPLACE

function_call ::=

hierarchical_function_identifier { attribute_instance } [ ( list_of_arguments ) ]

WITH

function_call ::=

hierarchical_function_identifier { attribute_instance } ( list_of_arguments )