package tezos-lwt-result-stdlib

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Signature

type key = H.t
type ('a, 'trace) t
val create : int -> ('a, 'trace) t
val clear : ('a, 'trace) t -> unit

clear tbl cancels and removes all the promises in tbl.

val reset : ('a, 'trace) t -> unit

reset tbl cancels and removes all the promises in tbl, and resizes tbl to its initial size.

val find_or_make : ('a, 'trace) t -> key -> (unit -> ('a, 'trace) result Lwt.t) -> ('a, 'trace) result Lwt.t

find_or_make tbl k make behaves differently depending on k being bound in tbl:

  • if k is bound in tbl then find_or_make tbl k make returns the promise p that k is bound to. This p might be already fulfilled with Ok _ or it might be pending. This p cannot be already fulfilled with Error _ or already rejected. This is because Error/rejected promises are removed from the table automatically. Note however that if this p is pending, p might become fulfilled with Error _ or become rejected.
  • if k is not bound in tbl then make () is called and the returned promise p is bound to k in tbl. Then p is returned. When p is resolved, it may be removed automatically from tbl as described above.
val remove : ('a, 'trace) t -> key -> unit

remove tbl k cancels the promise bound to k in tbl and removes it. If k is not bound in tbl it does nothing.

val find : ('a, 'trace) t -> key -> ('a, 'trace) result Lwt.t option
val mem : ('a, 'trace) t -> key -> bool
val iter_with_waiting_es : (key -> 'a -> (unit, 'trace) result Lwt.t) -> ('a, 'trace) t -> (unit, 'trace) result Lwt.t

iter_with_waiting_es f tbl iterates f over the bindings in tbl.

Specifically, for each binding (k, p) it waits for p to be fulfilled with Ok v and calls f k v. If p fulfills with Error _ or is rejected, then no call to f is made for this binding. Note however that an Error/rejection in one promise returned by f interrupts the iteration.

It processes bindings one after the other: it waits for both the bound promise to resolve and then the call promise to resolve before continuing to the next binding.

val iter_with_waiting_ep : (key -> 'a -> (unit, 'error) result Lwt.t) -> ('a, 'error) t -> (unit, 'error list) result Lwt.t

iter_with_waiting_ep f tbl iterates f over the bindings in tbl.

Specifically, for each binding (k, p) it waits for p to be fulfilled with Ok v and calls f k v. If p fulfills with Error _ or is rejected, then no call is made for this binding.

Note however that if one (or more) of the promises returned by f ends in Error/rejection, the final result of this promise is an Error/rejection. Even so, it only resolves once all the promises have.

It processes all bindings concurrently: it concurrently waits for all the bound promises to resolve and calls f as they resolve.

val fold_with_waiting_es : (key -> 'a -> 'b -> ('b, 'trace) result Lwt.t) -> ('a, 'trace) t -> 'b -> ('b, 'trace) result Lwt.t

fold_with_waiting_es f tbl init folds init with f over the bindings in tbl.

Specifically, for each binding (k, p) it waits for p to be fulfilled with Ok v and determines the next accumulator by calling f k v acc. If p fulfills with Error _ or is rejected, then no call is made for this binding.

It processes bindings one after the other.

val fold_keys : (key -> 'b -> 'b) -> ('a, 'trace) t -> 'b -> 'b
val fold_promises : (key -> ('a, 'trace) result Lwt.t -> 'b -> 'b) -> ('a, 'trace) t -> 'b -> 'b

fold_promises f tbl init folds over the table, passing the raw promises to f. This means that f can observe Error/rejections.

This can be used to, e.g., count the number of resolved/unresolved promises.

val fold_resolved : (key -> 'a -> 'b -> 'b) -> ('a, 'trace) t -> 'b -> 'b

fold_resolved f tbl init folds over the already resolved promises of tbl. More specifically, it folds over the v for all the promises fulfilled with Ok v that are bound in tbl.

val length : ('a, 'trace) t -> int
val stats : ('a, 'trace) t -> Hashtbl.statistics
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