Yet another extension of OCaml standard library.

Module name convension

  • X.Open: Recommended to open it when X is used
  • X.Pervasives: They are included in Spotlib.Spot. Opening Spotlib.Spot make them available.

Function name convension

Functions of stdlib are kept as they are. Only the exception is the conversions of non tail recursions to tail recursions.

Tail recursion

Non tail recursive functions in stdlib may be replaced by tail recursive equivalents. In that case, the original functions xxx in stdlib should be accessible by xxx_ntr.


Some functions xxx do not raise exceptions even for strange inputs. xxx_exn may throw exceptions for the strange inputs.

For example, List.take 10 [] = [] following the behaviour of Haskell's take. take_exn throws Invalid_argument "List.take" instead.


Many stdlib functions xxx throw exceptions Not_found when searching fails. xxx_opt returns None instead.


Many stdlib functions may raise exceptions for some inputs. xxx_def never throws exceptions for such inputs. Ex. String.sub and String.sub_default: String.sub "hello" 3 5 throws an exception, but String.sub_default "hello" 3 5 = "lo".

Function type convension

  • No labels for basic functions. Proposes to use flip, flip2... instead.