private OperatorNode<ExpressionOperator> readBinOp(ExpressionOperator op, ParseTree operand1, ParseTree operand2, Scope scope) {
        return OperatorNode.create(op, convertExpr(operand1, scope), convertExpr(operand2, scope));
    }
Translate the ANTLR grammar into the logical representation.
container-search/src/main/java/com/yahoo/search/yql/ProgramParser.java