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RBS, Ruby’s new type signature language

(developer.squareup.com)
511 points mootrichard | 1 comments | 29 Jul 20 18:04 UTC | HN request time: 0s | source
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setpatchaddress ◴[29 Jul 20 20:01 UTC] No.23990944[source]▶
I'm really puzzled by the decision to use a separate file for this. The stated justification ("it doesn't require changing Ruby code") doesn't make sense, and my personal experience with languages with external type specifications is strongly negative. It's an unbelievable pain to keep multiple interface files in sync over time.

`.h` files are not something to emulate! External interfaces should be generated by tools where needed.

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heavenlyblue ◴[29 Jul 20 20:08 UTC] No.23991013[source]▶
How do you even type local variables?
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RangerScience ◴[29 Jul 20 20:34 UTC] No.23991291[source]▶
Why would you need to?

Edit: Like, seriously. Either the local var is populated by something coming in externally (which is then typable) or, unless your code is too complex / large, it should be easy to see everywhere it's used, and then why would you need that additional typing info?

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1. frewsxcv ◴[29 Jul 20 21:33 UTC] No.23991831{3}[source]▶
If something is untyped in Sorbet, you can give it a type with `T.let`. So if the return value of function `foo` is untyped, but you have a high degree of confidence that it will return a `String`, you can do `ret = T.let(foo, String)`