LT abstract method
Get the Token instance associated with the value returned by
LA. This method has the same pre- and post-conditions as
IntStream.LA. In addition, when the preconditions of this method
are met, the return value is non-null and the value of
LT(k).getType()==LA(k)
.
TODO: in this doc it says that is non-null, but the implementation says otherwise
Se also: ntStream.LA
Implementation
Token? LT(int k);