When resp-main contains the value 13, buffer must contain either spaces or the name of a specific directive setting that is required. When the processor is next called, buffer contains the value of a directive setting. When the value 13 is first returned, the Compiler builds up a list of all of its directive settings and returns one value from it. Subsequent returns of this value return further values from this list. If a value other than 13 is returned at any point, further returns of value 13 cause the list to be generated again. The list of directives is generated in alphabetical order; once all directive settings have been returned, further calls yield spaces. If buffer contains spaces the first, or next, directive setting is returned; if buffer contains the name of a directive, the Compiler skips forward through its list to the specified directive. Only syntax-check phase directives are returned in this way.