这个Bool-producer对Maybe-producer函数是否出现在任何公共库中？ [英] Does this Bool-producer to Maybe-producer function appear in any common library?

问题描述

我发现自己想要这个小小的函数，但它似乎不在 Data.Maybe 中。

  splat ::（a  - > Bool） - > a  - >也许是
 splat c a 
 | c a =只是
 |否则= Nothing 
  

解决方案 ：//hackage.haskell.org/package/monadplusrel =nofollow> monadplus 完全包含这个函数，名为 部分 ：

  partial ::（a  - > Bool） - > a  - >可能是
  

I found myself wanting this tiny little function, but it doesn't seem to be in Data.Maybe. Is it somewhere else?

splat :: (a -> Bool) -> a -> Maybe a
splat c a
  | c a       = Just a
  | otherwise = Nothing

解决方案

The package monadplus contains exactly this function, named partial:

partial :: (a -> Bool) -> a -> Maybe a

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