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POScalaz Validation, validate inner value
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  1. POScalaz Validation, validate inner value
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    copied!<p>I have a Validation object</p> <pre><code>val v = Validation[String, Option[Int]] </code></pre> <p>I need to make a second validation, to check if actual Integer value is equals to 100 for example. If I do </p> <pre><code>val vv = v.map(_.map(intValue =&gt; if (intValue == 100) intValue.success[String] else "Bad value found".fail[Integer])) </code></pre> <p>I get:</p> <pre><code>Validation[String, Option[Validation[String, Int]]] </code></pre> <p>How is it possible to get vv also as Validation[String, Option[Int]] in most concise way</p> <p>=========</p> <p>Found possible solution from my own:</p> <pre><code>val validation: Validation[String, Option[Int]] = Some(100).success[String] val validatedTwice: Validation[String, Option[Int]] = validation.fold( _ =&gt; validation, // if Failure then return it _.map(validateValue _) getOrElse validation // validate Successful result ) def validateValue(value: Int): Validation[String, Option[Int]] = { if (value == 100) Some(value).success[String] else "Bad value".fail[Option[Int]] } </code></pre> <p>Looks not concise and elegant although it works</p> <p>==============</p> <p>Second solution from my own, but also looks over-compicated:</p> <pre><code>val validatedTwice2: Validation[String, Option[Int]] = validation.flatMap( _.map(validateValue _).map(_.map(Some(_))) getOrElse validation) def validateValue(value: Int): Validation[String, Int] = { if (value == 100) value.success[String] else "Bad value".fail[Int] } </code></pre>
 

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