package dolmen_loop

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Concrete pipelines.



Type definitions

type ('st, 'a, 'b) op

An operator from values of type 'a to value sof type 'b, and where a state value of type 'st is carried throughout.

type ('st, 'a, 'b) t

The type of pipelines from values of type 'a to values of type 'b, with state values of type 'st.

type 'st merge = 'st -> 'st -> 'st

Merge function used at the end of a fixpoint to get the resulting state.

type ('st, 'a) fix = [
  1. | `Ok
  2. | `Gen of 'st merge * ('st -> 'st * 'a option)

Type used to fixpoint expanding statements such as includes.

type ('a, 'b) cont = [
  1. | `Done of 'a
  2. | `Continue of 'b

Type used for continuation operators, allowing to leave the pipeline early.

type 'st k_exn = {
  1. k : 'a. 'st -> Stdlib.Printexc.raw_backtrace -> exn -> 'a;

Exception continuation to provide when evaluating a pipeline manually, in order to evaluate an exception handler with the most up-to-date state.

Creating operators

val op : ?name:string -> ('st -> 'a -> 'st * 'b) -> ('st, 'a, 'b) op

Base constructor function for operators.

val apply : ?name:string -> ('a -> 'b) -> (_, 'a, 'b) op

Create an operator from a function

val iter_ : ?name:string -> ('a -> unit) -> (_, 'a, 'a) op

Perform the function's side-effect and return the same input.

val f_map : ?name:string -> ?test:('st -> 'a -> bool) -> ('st -> 'a -> 'st * 'b) -> ('st, 'a, ('a, 'b) cont) op

TODO: doc

Creating pipelines

val _end : (_, 'a, 'a) t
val (@>>>) : ('st, 'a, 'b) op -> ('st, 'b, 'c) t -> ('st, 'a, 'c) t

Add an operator at the beginning of a pipeline.

val (@>|>) : ('st, 'a, ('b, 'c) cont) op -> ('st, 'c, 'b) t -> ('st, 'a, 'b) t

Add a continuation operator, allowing to stop evaluation of the pipeline early.

val (@|||) : ('st, 'a, 'b) t -> ('st, 'b, 'c) t -> ('st, 'a, 'c) t

Concatenate two pipeline. Whenever possible it is best to use (@>>>), which creates tail-rec pipelines.

val fix : ('st, 'a, ('st, 'a) fix) op -> ('st, 'a, unit) t -> ('st, 'a, unit) t

Perform a fixpoint expansion

Evaluating pipelines

val eval : exn:'st k_exn -> ('st, 'a, 'b) t -> 'st -> 'a -> 'st * 'b

Evaluate a pipeline to a function.

val run : finally:(State.t -> (Stdlib.Printexc.raw_backtrace * exn) option -> State.t) -> (State.t -> State.t * 'a option) -> State.t -> (State.t, 'a, unit) t -> State.t

Loop the evaluation of a pipeline over a generator, and starting options.

  • parameter finally

    a function called at the end of every iteration (even if an exception has been raised)


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