C# and F# lambda expressions code generation

Question

Let\'s look at the code, generated by F# for simple function:

let map_add valueToAdd xs =
    xs |> Seq.map (fun x -> x + valueToAdd)

The

Answer 1

Since they are compiler-generated, the sealed / public field issues are a bit moot - you shouldn't ever see it except via debug tools - how would you be subclassing it or mutating it, except by stepping around the compiler? If you have that level of debug access you can mutate it anyway (via reflection).

For C# it needs top be a field to allow certain ref / out usage, and to allow correct usage with captured mutable structs (yes, evil, we know). I assume F# is similar here (can you mutate a sub-[sub-[sub-]]member of the captured value?). The members could probably be internal, though.

Re [Serialziable]; why would something that underpins a closure be serializable? Delegates make extremely poor serialization candidates. Maybe the nature of F# means that it is better suited to persisting an operation (mid-flow) to disk - but in general, I wouldn't recommend it. I would have no expectation of these objects (iterators and capture-classes) being serialzable.