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Iterate a list of functions A => Option[B] returning the first Some
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| object play { | |
| import scalaz._ | |
| import Scalaz._ | |
| def foo(i: Int) = if (i > 0) Some(i) else None | |
| def boo(i: Int) = if (i <= 0) Some(0) else None | |
| val l = foo _ :: boo _ :: Nil | |
| l.foldMap(_.map(_.first)) apply -1 | |
| //> res0: scalaz.@@[Option[Int],scalaz.Tags.First] = Some(0) | |
| } |
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Nicely done. Purely to demonstrate that a new function is being produced (using the derived monoid as explained by Rahul), I might assign the result of the
foldMapto a value and then apply it with normal parens syntax.