to recommend using the LAST recognized part.
Means keeping a stack or backtracking, or something, and would be a
major annoyance. But clearly a big win for the user of an old reader
who reads what can be read and then executes the local "discard the rest
of the output" command.
I think it is probably worth it.
On the other hand, at the cost of slight additional complexity, one
might figure out a way to make a list of the types that would be
encountered when /alternate is defined. Then one could go hunting for
the last one that made sense without needing stacking or backtracking
mechanisms.
--john