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0 pointspharmakom4y ago0 comments

> Java’s exceptions are pretty much the exact same sum type as in Rust, just with added syntactic sugar.

Except Java doesn’t actually return a result object that can be assigned to a variable by default.

0 comments

And in case of exceptions, why would that be useful?

(For other things, I agree that sum types are cool, and fortunately are supported in Java through sealed classes)

I don’t think sealed classes offer exhaustive pattern matching. Instead you have an if-else ladder of instanceof checks. This is not the same as most union type implementations.

kaba04y ago

They do with switch expressions. It is only type based for now, but deconstructs are coming with full blown pattern matching a la Haskell.

j / k navigate · click thread line to collapse

0 pointspharmakom4y ago0 comments

> Java’s exceptions are pretty much the exact same sum type as in Rust, just with added syntactic sugar.

Except Java doesn’t actually return a result object that can be assigned to a variable by default.

0 comments

kaba04y ago

And in case of exceptions, why would that be useful?

(For other things, I agree that sum types are cool, and fortunately are supported in Java through sealed classes)

pharmakomOP4y ago

I don’t think sealed classes offer exhaustive pattern matching. Instead you have an if-else ladder of instanceof checks. This is not the same as most union type implementations.

kaba04y ago

They do with switch expressions. It is only type based for now, but deconstructs are coming with full blown pattern matching a la Haskell.

j / k navigate · click thread line to collapse