Add some FlatMap loops useful for State and Effects #2249
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| * for polling type operations on State (or RNG) Monads, or in effect | ||
| * monads. | ||
| */ | ||
| def untilDefined(implicit F: FlatMap[F]): F[A] = |
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I didn't name this the same as untilDefinedM because it is slightly different. OptionT[F, Option[A]] should still have access to untilDefinedM. This can possibly be removed since it adds little over optt.value.untilDefinedM
Codecov Report
@@ Coverage Diff @@
## master #2249 +/- ##
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+ Coverage 94.95% 94.96% +<.01%
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Files 333 333
Lines 5788 5797 +9
Branches 221 221
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+ Hits 5496 5505 +9
Misses 292 292
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| case Left(big) => big should === (1001) | ||
| case Right((_, _)) => fail("unreachable code due to Nothing, but scalac won't let us match on it") | ||
| } | ||
| } |
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nitpick. The current implementation looks stack safe, but shall we still add a stack safety test for future guard rail?
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@kailuowang look good now? |
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Thanks for adding the test. @johnynek |
Three cases I have wanted:
Gen[Option[A]] => Gen[A]IO[Unit]then repeating that forever.S => IO[S]that each call updates the state and repeat forever.This has to be done with syntax backwards compatibility hacks, but we can repair that at cats 2.0