72 lines
2.8 KiB
Markdown
72 lines
2.8 KiB
Markdown
# kotlin-result
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[`Result<V, E>`][Result] is a monad for modelling success ([`Ok`][Result.Ok]) or
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failure ([`Error`][Result.Error]) operations.
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## Inspiration
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Inspiration for this library has been drawn from other languages in which the
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Result monad is present, including:
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- [Elm](http://package.elm-lang.org/packages/elm-lang/core/latest/Result)
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- [Haskell](https://hackage.haskell.org/package/base-4.10.0.0/docs/Data-Either.html)
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- [Rust](https://doc.rust-lang.org/std/result/)
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It also iterates on other Result libraries written in Kotlin, namely:
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- [danneu/kotlin-result](https://github.com/danneu/kotlin-result)
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- [kittinunf/Result](https://github.com/kittinunf/Result)
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Improvements on the existing solutions include:
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- Complete feature parity with Result types from other languages including Elm,
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Haskell, & Rust
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- Lax constraints on `value`/`error` nullability
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- Lax constraints on the `error` type's (does not inherit from `Exception`)
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- Top level `Ok` and `Error` classes avoids qualifying usages with
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`Result.Ok`/`Result.Error` respectively
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- Higher-order functions marked with the `inline` keyword for reduced runtime
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overhead
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- Extension functions on `Iterable` & `List` for folding, combining, partitioning
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- Consistent naming with existing Result libraries from other languages (e.g.
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`map`, `mapError`, `mapBoth`, `mapEither`, `and`, `andThen`, `or`, `orElse`,
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`unwrap`)
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- Extensive test suite with over 50 unit tests and every library method covered
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## Installation
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This project is available in the [Maven Central Repository][maven-central]
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repository. The artifacts are signed with my personal [GPG key][gpg].
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```groovy
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repositories {
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mavenCentral()
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}
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dependencies {
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compile 'com.mikebull94.kotlin-result:kotlin-result:1.0.0'
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}
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```
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## Getting Started
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The [unit tests][unit-tests] are a good source of examples for using the library
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as they cover every avaiable method.
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Mappings from common Result libraries are available on the [wiki][wiki]:
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- [Elm][wiki-elm]
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- [Haskell][wiki-haskell]
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- [Rust][wiki-rust]
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[Result]: https://github.com/michaelbull/kotlin-result/blob/master/src/main/kotlin/com/mikebull94/result/Result.kt#L8
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[Result.Ok]: https://github.com/michaelbull/kotlin-result/blob/master/src/main/kotlin/com/mikebull94/result/Result.kt#L13
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[Result.Error]: https://github.com/michaelbull/kotlin-result/blob/master/src/main/kotlin/com/mikebull94/result/Result.kt#L29a
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[maven-central]: http://search.maven.org/
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[gpg]:https://www.michael-bull.com/gpg.asc
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[unit-tests]: https://github.com/michaelbull/kotlin-result/tree/master/src/test/kotlin/com/mikebull94/result
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[wiki]: https://github.com/michaelbull/kotlin-result/wiki
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[wiki-elm]: https://github.com/michaelbull/kotlin-result/wiki/Elm
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[wiki-haskell]: https://github.com/michaelbull/kotlin-result/wiki/Haskell
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[wiki-rust]: https://github.com/michaelbull/kotlin-result/wiki/Rust
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