Created
December 14, 2011 11:59
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Either[L,Either[L,R]]のように多段になる場合にRだけを取得する
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| def eith[R](arg: Either[Throwable, Any] ) : R = { | |
| arg match { | |
| case Left(e) => throw e | |
| case Right(o:Either[Throwable, Any]) => eith(o) | |
| case Right(o:R) => o | |
| } | |
| } |
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この定義だと、eith Stringのようにして呼び出すか、
val x: Int = eith(eitherObj)
のように、R の型をうまく推論できるパターンでないと、R = Nothingとして推論されてしまい不便なので、ちょっと改良版？を作ってみました。
https://gist.github.com/1476542