[Haskell-cafe] lens and Maybe value

PICCA Frederic-Emmanuel frederic-emmanuel.picca at synchrotron-soleil.fr
Tue Dec 20 16:25:35 UTC 2022



----- Le 20 Déc 22, à 17:18, David Feuer david.feuer at gmail.com a écrit :

> Please clarify your question. Your code doesn't compile, and I can't tell
> what it's supposed to do.


replace a (Maybe a) value in a data using lens only if the new (Maybe a) is a Just

Is it clearer ?


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