Applicative Functors/Selective Applicative Functors should be more suitable to serialization than monads, because they do not contain lambdas and expose the underlying structure, allowing you to inspect,modify it, etc.:

https://www.cs.ox.ac.uk/jeremy.gibbons/publications/delivery... http://simonmar.github.io/bib/papers/haxl-icfp14.pdf https://www.staff.ncl.ac.uk/andrey.mokhov/selective-functors...

Applicatives still contain lambdas in the same sense that monads do, no?

I think you can think of applicative like specifying the abstract syntax tree for the operation you want to perform and then giving it to an evaluator, as opposed to a monad where you code the implementation more directly, but deliver it opaquely as a lambda to the system.

Presumably you execute it with an instance that does serialization instead of interpretation.

This is correct. (Something else to add on here: Initial and final encodings are bijective – theoertically, anything one can do, the other can too.)

But you can't serialize a function - that's the whole point of the post.

But if you're writing an interpreter, you can serialize the result of 'evaluating' the structure of your 'function' made out of components that are being interpreted by your code, thus turning your 'function' (when evaluated with one set of code) into a data structure (when evaluated by something that serializes each of the components making up your function)

At that point you've already evaluated it and can't recover the original program - you're serializing the result of interpretation, not the computation to be interpreted. Since that computation might contain arbitrary functions, the only way to serialize that would be if you had a way of serializing arbitrary functions.