The API can later be expanded, in two ways:
gawkpasses an “extension id” into the extension when it first loads the extension. The extension then passes this id back to
gawkwith each function call. This mechanism allows
gawkto identify the extension calling into it, should it need to know.
gawkwhen it registers each extension function. This accommodates a possible future mechanism for grouping extension functions and possibly avoiding name conflicts.
Of course, as of this writing, no decisions have been made with respect to any of the above.