Add fixes to Monads found by new Law checks #120
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pakoito
requested review from
raulraja,
ffgiraldez,
jrgonzalezg and
JorgeCastilloPrz
…g with default and named parameters.
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## master #120 +/- ##
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Coverage ? 55.46%
Complexity ? 199
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Files ? 80
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Branches ? 165
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Hits ? 644
Misses ? 449
Partials ? 68
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Note that the Eq instance in the laws cannot be a default value because of this bug: https://youtrack.jetbrains.com/issue/KT-18660 |
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| package kategory | |||
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| interface Eq<in F> : Typeclass { | |||
| !eqv(a, b) | ||
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| companion object { | ||
| operator fun <F> invoke() = object : Eq<F> { |
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I think this should be a default instance of Eq[Any] outside of this object.
| @@ -10,7 +10,7 @@ import org.junit.runner.RunWith | |||
| class EitherTTest : UnitSpec() { | |||
| init { | |||
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| testLaws(MonadLaws.laws(EitherTMonad<Id.F, Int>())) | |||
| testLaws(MonadLaws.laws(EitherTMonad<Id.F, Int>(), Eq())) | |||
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Probably better named as EqAny
| @@ -8,7 +8,10 @@ import org.junit.runner.RunWith | |||
| class EvalTest : UnitSpec() { | |||
| init { | |||
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| testLaws(MonadLaws.laws(Eval)) | |||
| testLaws(MonadLaws.laws(Eval, object : Eq<HK<Eval.F, Int>> { | |||
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We should have this instance in the core not just in tests and there should be an instance for each one of the datatypes we implement.
| @@ -8,7 +8,10 @@ import org.junit.runner.RunWith | |||
| class Function0Test : UnitSpec() { | |||
| init { | |||
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| testLaws(MonadLaws.laws(Function0)) | |||
| testLaws(MonadLaws.laws(Function0, object : Eq<HK<Function0.F, Int>> { | |||
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We should have this instance in the core not just in tests.
| @@ -2,3 +2,5 @@ package kategory | |||
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| data class Law(val name: String, val test: () -> Unit) | |||
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| inline fun <reified A> A.equalUnderTheLaw(b: A, eq: Eq<A> = Eq()): Boolean = | |||
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Can we have extension functions that are inline reify... <F, ..> Once we have instances for the datatypes as part of our effort to provide syntax all datatypes will include syntax for eqv and neqv which can be used directly here provided thre is a registeres Eq instance for the datatype being compared.
| Law("Monad Laws: kleisli left identity", { kleisliLeftIdentity(M) }), | ||
| Law("Monad Laws: kleisli right identity", { kleisliRightIdentity(M) }), | ||
| Law("Monad Laws: map / flatMap coherence", { mapFlatMapCoherence(M) }), | ||
| Law("Monad / JVM: stack safe", { mapFlatMapCoherence(M) }) |
This PR adds some missing functions and equality check required for some monads to be lawful.