How do I handle the Maybe result of at in Control.Lens.Indexed without a Monoid instance
- by Matthias Hörmann
I recently discovered the lens package on Hackage and have been trying to make use of it now in a small test project that might turn into a MUD/MUSH server one very distant day if I keep working on it.
Here is a minimized version of my code illustrating the problem I am facing right now with the at lenses used to access Key/Value containers…