Scala

Mappings from Scala's Either type to kotlin-result.

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Either.fold

<V, E, U, F> Result<V, E>.mapEither(success: (V) -> U, failure: (E) -> F): Result<U, F>

Applies success if this is Ok or failure if this is an Err.

val result = possiblyFailingOperation()
logger.info(result.mapEither(
    success = { "Operation produced value: ${it.value}" },
    failure = { "Operation failed with ${it.reason}" }
))

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Either.getOrElse

<V, E> Result<V, E>.getOr(default: V): V

Returns the value from this Ok or the given argument if this is an Err.

Ok(12).getOr(17) // 12
Err(12).getOr(17)  // 17

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Either.map

<V, E, U> Result<V, E>.andThen(transform: (V) -> Result<U, E>): Result<U, E>

The given function is applied if this is Ok.

Ok(12).andThen { "flower" } // Result: Ok("flower")
Err(12).andThen { "flower" }  // Result: Err(12)

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Either.toOption

<V, E> Result<V, E>.get(): V?

Returns the value if it exists or null if this is an Err.

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MergeableEither.merge

<V : U, E : U, U> Result<V, E>.merge(): U

Allows use of a merge method to extract values from Result instances regardless of whether they are Ok or Err.