This is one of the most succinct tweets ever. Tony Morris just says it like it is: “Control.Lens.Fold”.
this is totally unhelpful though, obviously. and might not even be completely correct. it’s the kind of thing that is suitable for twitter; but not at all interesting here.
Putting aside transducers, here’s some stuff that might interest:
The second part was posted last night: Transducers Explained: Pipelines
Still, I would not say that it is totally unhelpful or that it isn’t correct. So I disagree with the downvotes. Also see:
http://www.reddit.com/r/haskell/comments/2cv6l4/clojures_transducers_are_perverse_lenses/ for more information. I begin to think that each time one posts something that does not appeal to the deepest fans of a language that is /not/ their favorite language, there is a downvote. And in the meanwhile, there is an upvote from those who do appreciate it. We are not being objective here, are we. Anyway, moving on.
For what it’s worth, I did find this interesting. I upvoted the list of links from the Haskell wiki so I can dig into the meaning behind the post.
The succinctness of the explanation is certainly helpful for people already familiar with Haskell and the concept of Control.Lens.Fold. That should not discredit, of course, any effort to explain perhaps difficult concepts to a wider audience. This is just a general observation, I know that was not your intent.
I did not downvote your post. I also did not upvote it. If you had posted a comment on another thread discussing transducers and mentioned the similarity to Control.Lens.Fold in Haskell and provided a link, I would have certainly upvoted it. You are right, it is helpful to realize there is a relationship to existing concepts when you are trying to understand something.
Thank you for bringing this to my attention.