Feature-based matching. Match if the given nodes have a variable called varName with non-zero value.
<fromRuleEltNumber,toRuleEltNumber>var(varName);
fromRuleEltNumber - type: int
toRuleEltNumber - type: int
varName - type: string
# The example counts nouns that have a non-zero feature (i.e., node
variable) called "mass".
@PRE
<1,1> var("mass");
@POST
++G("count mass nouns");
@RULES
_xNIL <-
_noun
@@
varz, vareq, varne, PRE Actions