presto-spi/src/main/java/io/prestosql/spi/type/TypeSignature.java/TypeSignature/formatValue
class TypeSignature:    private String formatValue(boolean json)
    {
        if (parameters.isEmpty()) {
            return base;
        }

        if (base.equalsIgnoreCase(StandardTypes.VARCHAR) &&
                (parameters.size() == 1) &&
                parameters.get(0).isLongLiteral() &&
                parameters.get(0).getLongLiteral() == VarcharType.UNBOUNDED_LENGTH) {
            return base;
        }

        StringBuilder typeName = new StringBuilder(base);
        typeName.append("(").append(json ? parameters.get(0).jsonValue() : parameters.get(0).toString());
        for (int i = 1; i < parameters.size(); i++) {
            typeName.append(",").append(json ? parameters.get(i).jsonValue() : parameters.get(i).toString());
        }
        typeName.append(")");
        return typeName.toString();
    }