> Any connection to transducers? Yep! On the fancy Haskell lens hierarchy (hackage.haskell.org/package/lens) we have the notion of a fold or a "getter which t

> Any connection to transducers? Yep! On the fancy Haskell lens hierarchy (hackage.haskell.org/package/lens) we have the notion of a fold or a "getter which touches multiple items". The existence of a fold for a type like `Fold s a` indicates that we can extract from the type `s` some number (0 to many) `a` values in sequence. This is the idea of "Foldable" in Haskell. Given a foldable type `s` and a transducer we execute the transducer by passing the "build" reducer in and then "visiting" each value `a` inside of `s` with the reducer that the transducer returns (modulo the early stopping bit which is just sort of a Clojure-specific optimization). Essentially, the transducer is a notion of "visitation" which is invariant to how the final summary is constructed—essentially the same thing that's captured in the "getter which touches multiple items" of a Fold. So there really ought to be a way to treat any specter optic as a possibly very limited transducer. Essentially, the "read" component of a lens will correspond pretty directly. We can also see this by remembering that any pure transducer is semantically equivalent to a function `a -> [b]` which you can read as a way of finding 0-to-many `b` values "inside" of `a`.