Add successOrNothing and exceptionOrNull extensions #70
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Couple more useful extensions for gracefully escaping or capturing underlying throwables. `exceptionOrNull()` is borrowed from the analogous function for `kotlin.Result`.
| * failure. | ||
| */ | ||
| public inline fun <T : Any, E : Any> ApiResult<T, E>.successOrNothing( | ||
| body: (ApiResult.Failure<E>) -> Nothing |
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The use of Nothing here implies that body will never return (ie. it will throw) but there's no way to ensure that happens. Returning Unit would seem appropriate, but renaming the method to successOrUnit doesn't have the same ring
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The use of Nothing ensures that the body either throws or returns: https://www.zacsweers.dev/its-nothing/
Using Unit would actually not accomplish the goal of this function :)
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Combining Nothing with an inline function and non-local returns is a cool pattern 👍 .
I wonder if we should document this somehow. Like me, I expect many/most will probably have to refresh their memory about what exactly Nothing is for and come away with only half the story
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Does the type system not help make that clear here? If you tried to just use Unit or anything other than throw/return, this would fail to compile.
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Sorry, I wasn't clear. I'm not arguing for using Unit or any other return type. I'm suggesting that someone unfamiliar with Nothing will read the docs and see that they are expected to throw and stop all investigation there. They are likely to overlook the fact that a non-local return (made possible by the use of an inline function) is also a valid option.
I was trying to suggest that we document this a bit better to expose that supported usage.
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do you have a suggestion? Nothing is a pretty standard language feature of Kotlin so I'm not sure what exactly to say other than refer to its doc
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If it's not clear we could expand the doc to be along the line of;
Otherwise, calls [body] with the failure, which should throw or return.
Couple more useful extensions for gracefully escaping or capturing underlying throwables.
exceptionOrNull()is borrowed from the analogous function forkotlin.Result.