Enables an _xWILD element to have exceptions to a match or fail list.
except can be used with _xWILD rule elements on the right-hand side of a rule. It must be accompanied by a single match or fail list.
Match and fail cannot occur in the same rule element, or the logic would become murky. With the except modifier, match and fail are dominant, and except provides a list of exceptions.
# The rule below enables looking "inside" or "underneath"
a node (with the s singlet modifier)
for _noun, but prevents an _np from being reduced to
# an _np.
@RULES
_np <- _xWILD
[s one match=(_noun) except=(_np)] @@