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A comment on Grain: A strongly-typed functional programming language for the modern web. Parent comment

Re:Grain: A strongly-typed functional programming language f... by masklinn on Tuesday July 31, 2018 @05:54AM (#17651831)
> Obviously it'd be nice if that didn't happen, but I can't think of any alternative that would make sense.

Returning a sum of success + error, as e.g. Rust's Serde[0] or Elm's Json.Decode[1] do.

The developer gets the feedback that the operation has failed at runtime, but they also get the feedback that the operation can fail and they must handle it somehow at compile-time, even ignoring the issue is an explicit decision.

[0] https://docs.serde.rs/serde_json/de/fn.from_str.html

[1] http://package.elm-lang.org/packages/elm-lang/core/latest/Js...

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Re:Grain: A strongly-typed functional programming language f... by bad_user on Tuesday July 31, 2018 @08:41AM (#17652661)
In Scala too well grown libraries return errors via sum types, e.g. Either.

In Play this is actually something like JsSuccess/JsError, not an exception, although Play is pragmatic (aka dirty) at times, so it's possible that it has functions throwing exceptions.

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