module S: sig .. end

type 'a t = 'a React.signal 

The type for signals of type 'a.

val const : 'a -> 'a React.signal

const v is always v, [const v]_t = v.

val create : ?eq:('a -> 'a -> bool) -> 'a -> 'a React.signal * ('a -> unit)

create i is a primitive signal s set to i and a set function. set v sets the signal's value to v at the time it is called and triggers an update cycle.

Warning. send must not be executed inside an update cycle.

val value : 'a React.signal -> 'a

value s is s's current value.

Warning. If executed in an update cycle may return a non up-to-date value or raise Failure if the signal is not yet initialized.

val retain : 'a React.signal -> (unit -> unit) -> [ `R of unit -> unit ]

retain s c keeps a reference to the closure c in s and returns the previously retained value. c will never be invoked.

Raises. Invalid_argument on constant signals.

val stop : 'a React.signal -> unit

stop s, stops updating s. It conceptually becomes React.S.const with the signal's last value and cannot be restarted. Allows to disable effectful signals.

Note. If executed in an update cycle the signal may still update in the cycle.

val equal : ?eq:('a -> 'a -> bool) -> 'a React.signal -> 'a React.signal -> bool

equal s s' is true iff s and s' are equal. If both signals are React.S.constant eq is used between their value (defauts to structural equality). If both signals are not React.S.constant, physical equality is used.

val trace : ?iff:bool t -> ('a -> unit) -> 'a React.signal -> 'a React.signal

trace iff tr s is s except tr is invoked with s's current value and on s changes when iff is true (defaults to S.const true). For all t where [s]_t = v and (t = 0 or ([s]_t-dt= v' and eq v v' = false)) and [iff]_t = true, tr is invoked with v.

val hold : ?eq:('a -> 'a -> bool) -> 'a -> 'a React.event -> 'a React.signal

hold i e has the value of e's last occurrence or i if there wasn't any.

• [hold i e]_t = i if [e]_<=t = None
• [hold i e]_t = v if [e]_<=t = Some v

val app : ?eq:('b -> 'b -> bool) ->
       ('a -> 'b) React.signal -> 'a React.signal -> 'b React.signal

app sf s holds the value of sf applied to the value of s, [app sf s]_t = [sf]_t [s]_t.

val map : ?eq:('b -> 'b -> bool) -> ('a -> 'b) -> 'a React.signal -> 'b React.signal

map f s is s transformed by f, [map f s]_t = f [s]_t.

val filter : ?eq:('a -> 'a -> bool) ->
       ('a -> bool) -> 'a -> 'a React.signal -> 'a React.signal

filter f i s is s's values that satisfy p. If a value does not satisfy p it holds the last value that was satisfied or i if there is none.

• [filter p s]_t = [s]_t if p [s]_t = true.
• [filter p s]_t = [s]_t' if p [s]_t = false and t' is the greatest t' < t with p [s]_t' = true.
• [filter p e]_t = i otherwise.

val fmap : ?eq:('b -> 'b -> bool) ->
       ('a -> 'b option) -> 'b -> 'a React.signal -> 'b React.signal

fmap fm i s is s filtered and mapped by fm.

• [fmap fm i s]_t = v if fm [s]_t = Some v.
• [fmap fm i s]_t = [fmap fm i s]_t' if fm [s]_t = None and t' is the greatest t' < t with fm [s]_t' <> None.
• [fmap fm i s]_t = i otherwise.

val diff : ('a -> 'a -> 'b) -> 'a React.signal -> 'b React.event

diff f s is an event with occurrences whenever s changes from v' to v and eq v v' is false (eq is the signal's equality function). The value of the occurrence is f v v'.

• [diff f s]_t = Some d if [s]_t = v and [s]_t-dt = v' and eq v v' = false and f v v' = d.
• [diff f s]_t = None otherwise.

val changes : 'a React.signal -> 'a React.event

changes s is diff (fun v _ -> v) s.

val sample : ('b -> 'a -> 'c) -> 'b React.event -> 'a React.signal -> 'c React.event

sample f e s samples s at e's occurrences.

• [sample f e s]_t = Some (f ev sv) if [e]_t = Some ev and [s]_t = sv.
• [sample e s]_t = None otherwise.

val when_ : ?eq:('a -> 'a -> bool) ->
       bool React.signal -> 'a -> 'a React.signal -> 'a React.signal

when_ c i s is the signal s whenever c is true. When c is false it holds the last value s had when c was the last time true or i if it never was.

• [when_ c i s]_t = [s]_t if [c]_t = true
• [when_ c i s]_t = [s]_t' if [c]_t = false where t' is the greatest t' < t with [c]_t' = true.
• [when_ c i s]_t = i otherwise.

val dismiss : ?eq:('a -> 'a -> bool) ->
       'b React.event -> 'a -> 'a React.signal -> 'a React.signal

dismiss c i s is the signal s except changes when c occurs are ignored. If c occurs initially i is used.

• [dismiss c i s]_t = [s]_t' where t' is the greatest t' <= t with [c]_t' = None and [s]_t'-dt <> [s]_t'
• [dismiss_ c i s]₀ = v where v = i if [c]₀ = Some _ and v = [s]₀ otherwise.

val accum : ?eq:('a -> 'a -> bool) -> ('a -> 'a) React.event -> 'a -> 'a React.signal

accum e i is S.hold i (React.E.accum e i).

val fold : ?eq:('a -> 'a -> bool) ->
       ('a -> 'b -> 'a) -> 'a -> 'b React.event -> 'a React.signal

fold f i e is S.hold i (React.E.fold f i e).

val merge : ?eq:('a -> 'a -> bool) ->
       ('a -> 'b -> 'a) -> 'a -> 'b React.signal list -> 'a React.signal

merge f a sl merges the value of every signal in sl using f and the accumulator a.

[merge f a sl]_t = List.fold_left f a (List.map []_t sl).

val switch : ?eq:('a -> 'a -> bool) ->
       'a React.signal -> 'a React.signal React.event -> 'a React.signal

switch s es is s until there is an occurrence s' on es, s' is then used until there is a new occurrence on es, etc..

• [switch s es]_t = [s]_t if [es]_<=t = None.
• [switch s es]_t = [s']_t if [es]_<=t = Some s'.

val fix : ?eq:('a -> 'a -> bool) ->
       'a -> ('a React.signal -> 'a React.signal * 'b) -> 'b

fix i sf allow to refer to the value a signal had an infinitesimal amount of time before.

In fix sf, sf is called with a signal s that represents the signal returned by sf delayed by an infinitesimal amount time. If s', r = sf s then r is returned by fix and s is such that :

• [s]_t = i for t = 0.
• [s]_t = [s']_t-dt otherwise.

eq is the equality used by s.

Raises. Invalid_argument if s' is directly a delayed signal (i.e. a signal given to a fixing function).

Note. Regarding values depending on the result r of s', r = sf s the following two cases need to be distinguished :

• After sf s is applied, s' does not depend on a value that is in a cycle and s has no dependents in a cycle (e.g in the simple case where fix is applied outside a cycle).

  In that case if the initial value of s' differs from i, s and its dependents need to be updated and a special update cycle will be triggered for this. Values depending on the result r will be created only after this special update cycle has finished (e.g. they won't see the i of s if r = s).

• Otherwise, values depending on r will be created in the same cycle as s and s' (e.g. they will see the i of s if r = s).

val l1 : ?eq:('b -> 'b -> bool) -> ('a -> 'b) -> 'a React.signal -> 'b React.signal

val l2 : ?eq:('c -> 'c -> bool) ->
       ('a -> 'b -> 'c) -> 'a React.signal -> 'b React.signal -> 'c React.signal

val l3 : ?eq:('d -> 'd -> bool) ->
       ('a -> 'b -> 'c -> 'd) ->
       'a React.signal -> 'b React.signal -> 'c React.signal -> 'd React.signal

val l4 : ?eq:('e -> 'e -> bool) ->
       ('a -> 'b -> 'c -> 'd -> 'e) ->
       'a React.signal ->
       'b React.signal -> 'c React.signal -> 'd React.signal -> 'e React.signal

val l5 : ?eq:('f -> 'f -> bool) ->
       ('a -> 'b -> 'c -> 'd -> 'e -> 'f) ->
       'a React.signal ->
       'b React.signal ->
       'c React.signal -> 'd React.signal -> 'e React.signal -> 'f React.signal

val l6 : ?eq:('g -> 'g -> bool) ->
       ('a -> 'b -> 'c -> 'd -> 'e -> 'f -> 'g) ->
       'a React.signal ->
       'b React.signal ->
       'c React.signal ->
       'd React.signal -> 'e React.signal -> 'f React.signal -> 'g React.signal

module Bool: sig .. end

module Int: sig .. end

module Float: sig .. end

module Pair: sig .. end

module Compare: sig .. end

module type EqType = sig .. end

Input signature of React.S.Make

module type S = sig .. end

Output signature of React.S.Make

module Make: 
functor (Eq : EqType) -> S  with type 'a v = 'a Eq.t

Functor specializing the combinators for the given signal value type

module Special: sig .. end

Specialization for booleans, integers and floats.