<BinAndExpr> ::= <CompareExpr> ['&&' <BinAndExpr>]
<CompareExpr> ::= <PlusMinExpr> [('==' | '<' | '>' | '<=' | '>=' | '!=') <CompareExpr>]
<PlusMinExpr> ::= <TimesDivExpr> (('+' | '-') <TimesDivExpr>)*
-<TimesDivExpr> ::= <BasicExpr> ('*' | '/' | '%'] <BasicExpr>)*
+<TimesDivExpr> ::= <BasicExpr> (['*' | '/' | '%'] <BasicExpr>)*
<BasicExpr> ::= <id> <FieldSels>
| <Op1> <Expr>
| <int>