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Comment by sam0x17 | Hacker News Reader

Another big area that is lacking is Go makes it so hard if you want to use something other than a primitive as a hash key (Rust is guilty of this as well, mind you). This is something that should come out of the box in any modern language in my opinion.

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> Rust is guilty of this as well, mind you

#[derive(Hash)] struct X{ ... }

Seems easy enough to me? The only annoyance is if a third party type didn't implement Hash, but you can solve that with a manual implementation instead of a derive.

> you can solve that with a manual implementation instead of a derive.

How? I thought the orphan rule said you can only define trait implantations at struct definition or trait definition

ding ding ding! This has been a problem for me a number of times. The quick workaround is pray that it implements Debug and in a reasonable way and take the hash of the string instead

Yeah, for foreign types you will have to use the "newtype" pattern, aka: define your own wrapper struct.

Maybe I misunderstood you, but you can use structs as keys of a map.

not if it doesn't have equailty defined. Then you have to define it. Oh, and it's an AST node someone at X company wrote and there are 100+ node types. Have fun!

In crystal there is a reasonable data-based default hash implementation that you can just rely on.

The map key type can be anything for which `==` is defined. This includes structs for which `==` is defined for every field. Composite keys etc are trivial.

https://go.dev/ref/spec#Map_types

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