Feature/arrowcontracts

[sksamuel]

I've added contracts for Validated, Either and Option.
These contracts allow us to extract the field from these datatypes, but because of the issue with contracts not supporting generics yet, the extracted field will be Any?.
This is still a big improvement I think, and also means when contracts support generics (1.4?) we can easily update these matchers.

Current example:

val either = "foo".right()
either.shouldBeRight()
(either as Either.Right<String>).b shouldBe "foo"
(either as Either.Right<String>).b.length shouldBe 3

Example with this PR:

val either = "foo".right()
either.shouldBeRight()
either.b shouldBe "foo"
(either.b as String).length shouldBe 3

Example in the future:

val either = "foo".right()
either.shouldBeRight()
either.b shouldBe "foo"
either.b.length shouldBe 3

This partially addresses the feature request of #612

[LeoColman]

Is this actually necessary?

I remember adding a experimental contract somewhere else in our code, and I don't think I needed to add this.

[sksamuel]

Yeah you need it where the contract is defined, but not where it is used.

[LeoColman]

We wanted this to be the generic type, but it's not possible due to contracts not supporting it yet, right?

[sksamuel]

Yes, so once contracts support generics we can just change Either.Right<*> to Either.Right<T> and it will be generic.

[LeoColman]

Great. Let's merge this!

…

On Mon., Jun. 17, 2019, 12:16 Stephen Samuel, ***@***.***> wrote: ***@***.**** commented on this pull request. ------------------------------ In kotlintest-assertions/kotlintest-assertions-arrow/src/main/kotlin/io/kotlintest/assertions/arrow/either/matchers.kt <#834 (comment)>: > @@ -6,14 +6,20 @@ import io.kotlintest.Result import io.kotlintest.matchers.beInstanceOf2 import io.kotlintest.should import io.kotlintest.shouldNot +import kotlin.contracts.ExperimentalContracts +import kotlin.contracts.contract + ***@***.***(ExperimentalContracts::class) +fun <T> Either<*, T>.shouldBeRight() { + contract { + returns() implies ***@***.*** is Either.Right<*>) Yes, so once contracts support generics we can just change Either.Right<*> to Either.Right<T> and it will be generic. — You are receiving this because your review was requested. Reply to this email directly, view it on GitHub <#834>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAMBCI4HDMG7P4DQMNTN3PLP26TDPANCNFSM4HYOI2NA> .

[sksamuel]

Please do if you're happy. We can apply this strategy to other parts too. On Mon, 17 Jun 2019, 10:18 Leonardo Colman Lopes, <notifications@github.com> wrote:

…

Great. Let's merge this! On Mon., Jun. 17, 2019, 12:16 Stephen Samuel, ***@***.***> wrote: > ***@***.**** commented on this pull request. > ------------------------------ > > In > kotlintest-assertions/kotlintest-assertions-arrow/src/main/kotlin/io/kotlintest/assertions/arrow/either/matchers.kt > <#834 (comment) >: > > > @@ -6,14 +6,20 @@ import io.kotlintest.Result > import io.kotlintest.matchers.beInstanceOf2 > import io.kotlintest.should > import io.kotlintest.shouldNot > +import kotlin.contracts.ExperimentalContracts > +import kotlin.contracts.contract > + > ***@***.***(ExperimentalContracts::class) > +fun <T> Either<*, T>.shouldBeRight() { > + contract { > + returns() implies ***@***.*** is Either.Right<*>) > > Yes, so once contracts support generics we can just change Either.Right<*> > to Either.Right<T> and it will be generic. > > — > You are receiving this because your review was requested. > Reply to this email directly, view it on GitHub > < #834 >, > or mute the thread > < https://github.com/notifications/unsubscribe-auth/AAMBCI4HDMG7P4DQMNTN3PLP26TDPANCNFSM4HYOI2NA > > . > — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#834>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAFVSGQDIECOHK6Z6NSKKVDP26TMVANCNFSM4HYOI2NA> .