Regular Match Marker

     (preprocessor) A match marker indicating a position that will
     successfully match an arbitrarily complex expression in the source text.
     A regular match marker generally marks a part of a command that is
     expected to consist of arbitrary programmer-supplied text, as opposed to
     a keyword or other restrictive component.  In order for the source text
     to match, it must constitute a properly formed expression.  A regular
     match marker has the form <id>.  id associates a name with the match
     marker.  The name can be used in a result marker to specify how the
     matching source text is to be handled.