package brr

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Browser programming toolkit for OCaml

Install 

dune-project
 Dependency

erratique.ch Readme Changelog ISC; BSD-3-Clause License Edit opam file Versions (2)

Authors

  1. T
    The brr programmers

Maintainers

  1. Daniel Bünzli

Sources

brr-0.0.8.tbz
sha512=49e7bfbad2ea6a0139354e4a33c59c8a113c4c1e20a4f629bc5cad24aa801e474b4af10ce35adbda5d23dd294d1de5efa5b10bb3030d03f4758459977250a0f6

doc/brr/Fut/index.html

Module FutSource

Future values.

A future 'a Fut.t is an undetermined value of type 'a that becomes determined at an arbitrary point in the future. The future acts as a placeholder for the value while it is undetermined.

Future values do not support exceptions, you need to turn them into a value and make them appear in the future's type, for example using Fut.error.

Brr uses future values ('a, 'b) result Fut.t to type the resolution and rejection case of JavaScript promises. Since most rejection cases given by browser APIs are simply Jv.Error.t values, the dedicated Fut.or_error type alias can be used for that.

Fut.t values are indirectly implemented as Promise objects that never reject. You can't substitute them directly for JavaScript promises and vice-versa, use of_promise and to_promise to convert between them.

Futures

Sourcetype 'a t

The type for futures with value of type 'a.

Sourceval create : unit -> 'a t * ('a -> unit)

create () is (f, set with f the future value and set the function to set it. The latter can be called only once, a Jv.Error is thrown otherwise.

Sourceval await : 'a t -> ('a -> unit) -> unit

await f k waits for f to determine v and continues with k v. If the future never determines k is not invoked. k must not raise.

Sourceval return : 'a -> 'a t

return v is a future that determines v.

Sourceval map : ('a -> 'b) -> 'a t -> 'b t

map fn f is return (fn v) with v the value determined by f. fn must not raise.

Sourceval bind : 'a t -> ('a -> 'b t) -> 'b t

bind f fn is the future fn v with v the value determined by f. fn must not raise.

Sourceval pair : 'a t -> 'b t -> ('a * 'b) t

pair f0 f1 is the future that determines with the value of f0 and f1.

Sourceval of_list : 'a t list -> 'a list t

of_list fs determines with the values of all future fs in the same order.

Sourceval tick : ms:int -> unit t

tick ~ms determines () ms milliseconds after creation using setTimeout.

Future results

Sourcetype nonrec ('a, 'b) result = ('a, 'b) result t

The type for future values that may error.

Sourcetype 'a or_error = ('a, Jv.Error.t) result

The type for future values that error with a JavaScript error.

Sourceval ok : 'a -> ('a, 'b) result

ok v is return (Ok v).

Sourceval error : 'b -> ('a, 'b) result

error e is return (Error e).

Converting with JavaScript promises

Sourceval of_promise : ok:(Jv.t -> 'a) -> Jv.Promise.t -> 'a or_error

of_promise ~ok p is of_promise' ~ok ~error:Jv.to_error. p.

Sourceval to_promise : ok:('a -> Jv.t) -> 'a or_error -> Jv.Promise.t

to_promise p is to_promise' ~ok ~error:Jv.of_error p.

Sourceval of_promise' : ok:(Jv.t -> 'a) -> error:(Jv.t -> 'b) -> Jv.Promise.t -> ('a, 'b) result

of_promise ~ok ~error p is a future for the promise p. The future determines with Ok (ok v) if p resolves with v and with Error (error e) if p rejects with e.

Sourceval to_promise' : ok:('a -> Jv.t) -> error:('b -> Jv.t) -> ('a, 'b) result -> Jv.Promise.t

to_promise f is a JavaScript promise for the future f that resolves the promise with ok v if the future determines with Ok v and rejects with e if the future determines with Error e.

Future syntaxes

Sourcemodule Syntax : sig ... end

Future syntax.

Sourcemodule Result_syntax : sig ... end

Future result syntax.