Sounds like a bad idea to me. Even though Num doesn't have an explicit contract,... | Hacker News

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nandemo on April 20, 2013 | parent | context | favorite | on: Why Maybe Is Better Than Null

Sounds like a bad idea to me. Even though Num doesn't have an explicit contract, we sort of expect it to behave "nicely".

But here we start with a nice ring like Integer and end up with a type that has this weird, extra element that has no inverse with respect to addition, etc.

danbruc on April 20, 2013 [–]

For all fixed length two's complement integer types the smallest representable number has no additive inverse, too.

dllthomas on April 20, 2013 | [–]

Prelude Data.Int> minBound + minBound :: Int16

0

danbruc on April 20, 2013 | | [–]

Ohhh yes, of course, it is still a abelian group.

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