reactiveData

Functional reactive programming with incremental changes in data structures
IN THIS PACKAGE
Module ReactiveData . RList
type 'a p =
| I of int * 'a(*

I (i, v) adds v at position i

*)
| R of int(*

R i removes i-th element

*)
| U of int * 'a(*

U (i, v) substitutes i-th element with v

*)
| X of int * int(*

X (i, j) swaps the i-th and j-th elements

*)

Patch operation on lists. All operations are of linear complexity.

type 'a patch = 'a p list

A patch is a list of patch operations. The operations are applied in the order they appear in the list.

The indices correspond to list contents after the operations that appear earlier in the list have been applied, not to the contents before the whole patch operation.

A patch comprised of I, R, and U steps with increasing indices can be applied in time O(m + n), where m is the patch length and n is the current size of the list. (Arbitrary patches are slower, requiring O(m * n).)

include S with type 'a data = 'a list and type 'a patch := 'a patch
type 'a t

Reactive version of the data container

type 'a data = 'a list

Raw (non-reactive) version of the data container

type 'a msg =
| Patch of 'a patch(*

Patch p triggers the application of p on the current contents

*)
| Set of 'a data(*

With Set d, d becomes the new content

*)

Message format

type 'a handle

Handle that permits applying incremental updates

val empty : 'a t

Empty data structure

val create : 'a data -> 'a t * 'a handle

Build a container from initial contents. The handle can be used for performing reactive updates.

val from_event : 'a data -> 'a msg React.E.t -> 'a t

from_event d e is a container whose initial value is d, and which gets updated for every occurrence of e

val from_signal : ?eq:( 'a -> 'a -> bool ) -> 'a data React.S.t -> 'a t

Convert a React signal into a ReactiveData container.

Whenever the signal changes from value v to value v', we detect the differences between v and v', and perform downstream computation (e.g., for map) only on the new and modified elements.

val const : 'a data -> 'a t

Produce a constant container

val patch : 'a handle -> 'a patch -> unit

patch h p applies p on the container corresponding to h

val set : 'a handle -> 'a data -> unit

set h d sets the contents of the container corresponding to h, disregarding previous contents

val map_msg : ( 'a -> 'b ) -> 'a msg -> 'b msg

Transform a message

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

map f c applies f on all elements of c, producing a new reactive container c'. Modifying the contents of c leads to modifications of c'. f is applied only on the new or modified elements of c.

val value : 'a t -> 'a data

Return current contents

val fold : ( 'a -> 'b msg -> 'a ) -> 'b t -> 'a -> 'a React.signal

fold f c v accumulates the updates on c with f starting from v.

The result is a signal of value f m_n (f ... (f m_1 v)), where m_1 ... m_n are the messages that have been applied since the beginning of fold. m_1 is a pseudo-message Set l, accounting for the contents l of c at the time when accumulation starts.

val signal : ?eq:( 'a -> 'a -> bool ) -> 'a t -> 'a data React.S.t

Signal corresponding to contents

val event : 'a t -> 'a msg React.E.t

Event whose occurrences correspond to container updates

val cons : 'a -> 'a handle -> unit

Add element to the beginning

val snoc : 'a -> 'a handle -> unit

Add element to the end

val insert : 'a -> int -> 'a handle -> unit

insert v i h adds v as the i-th position in the container corresponding to h. The indices of the subsequent elements change.

val remove : int -> 'a handle -> unit

remove i h removes the i-th position from the container corresponding to h. The indices of the subsequent elements change.

val update : 'a -> int -> 'a handle -> unit

update v i h substitutes the i-th element of the container corresponding to h with v

val move : int -> int -> 'a handle -> unit

move i j h moves the i-th element of the container corresponding to h to the j-th position, modifying the indices of other elements

val singleton : 'a -> 'a t

Produce container list containing a single, constant element

val singleton_s : 'a React.S.t -> 'a t

Produce reactive list containing a single element that gets updated based on a signal

val concat : 'a t -> 'a t -> 'a t

concat a b is the concatenation of a and b, and it gets updated whenever a and b change

val rev : 'a t -> 'a t

rev a is the reversal of a; rev a gets updated along with a