Yesod Esqueleto isJust
Question
我一直在使用isNothing ，从Esqueleto ，但现在我想只是测试，如果它是not null ，我注意到，没有isJust ，我想知道它是不存在的原因，有什么事情我想达到类似的效果： isJust (a ^. MyEntityMyField)
1 answers
solution1
3 ACCPTED 2016-05-27 13:58:24
你不能自己定义吗？
isJust = not_ . isNothing
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