[namelosw]

I tend to agree. Algebraic data types (product and sum types) is essential for modeling. Missing sum type would be incomplete in terms of modeling.

A lot of obscure OO code I have seen is related to modeling sum types of products (or parameterized enumerated in some language), or the lack of it in mainstream languages.

The problem applies to SQL as well. If I make everything into the same table and leave many columns empty I’m not modeling at all. But if I split them into tables it defeat most basic SQL functionalities like SELECT * FROM my_sum_type.