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ghostpepper on Feb 18, 2023 | parent | context | favorite | on: John Carmack on Functional Programming in C++ (201...

Can you explain the term 'cartesian product' in this context? I'm familiar with the cross product from undergrad linear algebra but I haven't applied algebra to types before, and I don't understand what two sets would produce a single Int as their product.

I haven't studied much theoretical computer science so I'd love to hear some good beginner resources on this stuff.

thesz on Feb 18, 2023 | [–]

Cartesian product: https://en.wikipedia.org/wiki/Cartesian_product

The number of variants of the AnIntPair construction is the number of distinct elements in the Int type, squared.

I used definition of algebraic data type in Haskell: http://wiki.haskell.org/Algebraic_data_type

justinpombrio on Feb 18, 2023 | [–]

"Cartesian product" is a fancy word for "pair". Or more generally "tuple".

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