PFPCaml

A port of the library described in this 2006 paper from Haskell to OCaml. This was ill-advised, because I didn't know Haskell or OCaml. I thought this would be a good opportunity to get comfortable with both. Also, the actual library has got some pretty interesting concepts.

I've translated the core of the module, Probability.hs (from the original 2006 version) to OCaml.

A lot of the time, this felt like trying to fit a round peg into a square hole:

• Type Definitions:

  • Haskell uses newtype for Probability, while OCaml uses type.
  • Haskell defines Dist as a newtype, whereas OCaml uses a regular type definition.

• Monad and Functor Instances:

  • Haskell defines Monad and MonadPlus instances for Dist.
  • OCaml uses functions like bind and mplus to achieve similar functionality.

• Random Values:

  • Haskell uses the IO monad for random values (R type).
  • OCaml uses a function type unit -> 'a for random values (random type).

• Pretty Printing:

  • Haskell uses the Show typeclass for pretty printing.
  • OCaml uses functions like show_dist for pretty printing.

• Expected Value Calculation:

  • Haskell uses the Expected typeclass.
  • OCaml uses a module type Expected and functors to achieve similar functionality.

• Iteration and Simulation:

  • Haskell uses the Iterate and Sim typeclasses.
  • OCaml uses modules and functors to define similar behavior.

• Conditional Probability:

  • Haskell uses the ||| operator for filtering distributions.
  • OCaml uses the ||| operator for similar functionality but implemented differently.

• Randomized Generators:

  • Haskell defines RChange and RTrans types for random changes and transitions.
  • OCaml defines similar types but uses different naming conventions and implementations.