VMS Help DECset, Context File, SET_MMS, Parameters, MACRO  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  This option has the same semantics as the MMS /MACRO qualifier.

  Format:

       SET_MMS MACRO=(macro[,...])
       SET_MMS MACRO="macroname=expansion"

  The macro argument in the MACRO=(macro[,...]) form can be in
  either of the following forms:

       "macroname=expansion"
       macro-filespec