Module Effect.Deep

Deep handlers

type ('a, 'b) continuation

('a,'b) continuation is a delimited continuation that expects a 'a value and returns a 'b value.

val continue : ('a, 'b) continuation -> 'a -> 'b

continue k x resumes the continuation k by passing x to k.

  • raises Continuation_already_taken

    if the continuation has already been resumed.

val discontinue : ('a, 'b) continuation -> exn -> 'b

discontinue k e resumes the continuation k by raising the exception e in k.

  • raises Continuation_already_taken

    if the continuation has already been resumed.

val discontinue_with_backtrace : ('a, 'b) continuation -> exn -> Printexc.raw_backtrace -> 'b

discontinue_with_backtrace k e bt resumes the continuation k by raising the exception e in k using bt as the origin for the exception.

  • raises Continuation_already_taken

    if the continuation has already been resumed.

type ('a, 'b) handler = {
  1. retc : 'a -> 'b;
  2. exnc : exn -> 'b;
  3. effc : 'c. 'c t -> (('c, 'b) continuation -> 'b) option;
}

('a,'b) handler is a handler record with three fields -- retc is the value handler, exnc handles exceptions, and effc handles the effects performed by the computation enclosed by the handler.

val match_with : ('c -> 'a) -> 'c -> ('a, 'b) handler -> 'b

match_with f v h runs the computation f v in the handler h.

type 'a effect_handler = {
  1. effc : 'b. 'b t -> (('b, 'a) continuation -> 'a) option;
}

'a effect_handler is a deep handler with an identity value handler fun x -> x and an exception handler that raises any exception fun e -> raise e.

val try_with : ('b -> 'a) -> 'b -> 'a effect_handler -> 'a

try_with f v h runs the computation f v under the handler h.

val get_callstack : ('a, 'b) continuation -> int -> Printexc.raw_backtrace

get_callstack c n returns a description of the top of the call stack on the continuation c, with at most n entries.