The best way to do it would be to get the representation of the function (if it can be recovered somehow). Binary serialization is preferred for efficiency reasons.
I think there is a way to do it in Clean, because it would be impossible to implement iTask, which relies on that tasks (and so functions) can be saved and continued when the server is running again.
This must be important for distributed haskell computations.
I'm not looking for parsing haskell code at runtime as described here: Serialization of functions in Haskell. I also need to serialize not just deserialize.
Unfortunately, it's not possible with the current ghc runtime system. Serialization of functions, and other arbitrary data, requires some low level runtime support that the ghc implementors have been reluctant to add.
Serializing functions requires that you can serialize anything, since arbitrary data (evaluated and unevaluated) can be part of a function (e.g., a partial application).