I'm working on a parser for a grammar in ANTLR. I'm currently working on expressions where () has the highest order precedence, then Unary Minus, etc.
When I add the line ANTLR gives the error: The following sets of rules are mutually left-recursive [add, mul, unary, not, and, expr, paren, accessMem, relation, or, assign, equal] How can I go about solving this issue? Thanks in advance.
Easiest answer is to use antlr4 not 3, which has no problem with immediate left recursion. It automatically rewrites the grammar underneath the covers to do the right thing. There are plenty of examples. one could for example examine the Java grammar or my little blog entry on left recursive rules. If you are stuck with v3, then there are earlier versions of the Java grammar and also plenty of material on how to build arithmetic expression rules in the documentation and book.