[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 ?

More information about the Haskell-Cafe mailing list