presto-parser/src/main/java/io/prestosql/sql/parser/AstBuilder.java/AstBuilder/getComparisonOperator
class AstBuilder:    private static ComparisonExpression.Operator getComparisonOperator(Token symbol)
    {
        switch (symbol.getType()) {
            case SqlBaseLexer.EQ:
                return ComparisonExpression.Operator.EQUAL;
            case SqlBaseLexer.NEQ:
                return ComparisonExpression.Operator.NOT_EQUAL;
            case SqlBaseLexer.LT:
                return ComparisonExpression.Operator.LESS_THAN;
            case SqlBaseLexer.LTE:
                return ComparisonExpression.Operator.LESS_THAN_OR_EQUAL;
            case SqlBaseLexer.GT:
                return ComparisonExpression.Operator.GREATER_THAN;
            case SqlBaseLexer.GTE:
                return ComparisonExpression.Operator.GREATER_THAN_OR_EQUAL;
        }

        throw new IllegalArgumentException("Unsupported operator: " + symbol.getText());
    }