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Agreed; also Traversable in Haskell is a simpler abstraction than lenses and pretty directly addresses what they seem to be looking for: https://hackage.haskell.org/package/base-4.21.0.0/docs/Data-...

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Traversable and lenses are very closely linked. If you go to the original paper leading to Traversable [1] and read through it, it feels basically identical to reading through the parts of the lens library that lay down the core abstractions and the laws implementations must follow if you want to be able to blindly manipulate them. In fact, the traverse function is a Traversal, and so fits trivially into the lens ecosystem.

[1] https://www.cs.ox.ac.uk/jeremy.gibbons/publications/iterator...

Arent haskell traversables different in that they preserve the structure if you were to map over them, as compared to the solution posted in the article, where they get flattened to what amounts to a list?

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