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Reminder: the way to remember the difference between sum and product types is to count the number of possible values. enum { A(int), B(int) } is a sum type because there are INT_MAX+INT_MAX possible values. (int, int) is a product type because there are INT_MAX*INT_MAX values.

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Patrick Walton

@pcwalton

Nov 16, 2021

(I don't love the theoretical PL terminology because "tagged union" and "tuple" are much clearer, but there you go.) (Also yes, I'm aware that INT_MAX doesn't take the negative integers into account, but you get the idea)

Brendan Zabarauskas

@brendanzab

Replying to

@pcwalton

Yeah I'm not the biggest fan of the type theory terminology too. It gets even more confusing with pi types and sigma types - there are good reasons for these names, but I prefer ‘dependent function type’ and ‘dependent pair type’ respectively.

4:14 AM · Nov 16, 2021Twitter Web App