lwd 0.2 · OCaml Package

Table manipulation

Lwd_table is an ordered collection with an impure interface. It is designed to be efficient in an interactive setting.

The interface mimics the one of a doubly-linked lists: from a node, called row, you can iterate backward and forward, insert and delete other nodes, and change the value it is bound to.

The sequence of nodes can be observed by map/reduce operations, that will be recomputed efficiently when sequence changes.

type 'a t

type 'a row

The type of tables

val make : unit -> 'a t

Create a new table

Inserting rows

val prepend : ?set:'a -> 'a t -> 'a row

Insert and return a new row at the start of a table. It can be optionnally initialized to the value of set.

val append : ?set:'a -> 'a t -> 'a row

Insert and return a new row at the end of a table. It can be optionnally initialized to the value of set.

val prepend' : 'a t -> 'a -> unit

val append' : 'a t -> 'a -> unit

val before : ?set:'a -> 'a row -> 'a row

Insert and return a new row just before an existing row. It can be optionnally initialized to the value of set.

If the input row is unbound (is_bound returns false), the returned row is too.

val after : ?set:'a -> 'a row -> 'a row

Insert and return a new row just after an existing row. It can be optionnally initialized to the value of set.

If the input row is unbound (is_bound returns false), the returned row is too.

Iterating over rows

val first : 'a t -> 'a row option

Returns the first row of a table, or None if the table is empty

val last : 'a t -> 'a row option

Returns the last row of a table, or None if the table is empty

val next : 'a row -> 'a row option

Returns the row next to another one, or None if the input row is unbound or is the last row

val prev : 'a row -> 'a row option

Returns the row just before another one, or None if the input row is unbound or is the first row

Accessing and changing row contents

val get : 'a row -> 'a option

Get the value associated with a row, if any, or None if the row is unbound

val set : 'a row -> 'a -> unit

Set the value associated with a row, or do nothing if the row is unbound

val unset : 'a row -> unit

Unset the value associated with a row

Removing rows

val is_bound : 'a row -> bool

Returns true iff the row is bound in a table (it has not beem removed yet, the table has not been cleared)

val remove : 'a row -> unit

remove a row from its table, is_bound will be true after that

val clear : 'a t -> unit

Remove all rows from a table

Observing table contents

val reduce : 'a Lwd_utils.monoid -> 'a t -> 'a Lwd.t

Observe the content of a table by reducing it with a monoid

val map_reduce : 
  ('a row -> 'a -> 'b) ->
  'b Lwd_utils.monoid ->
  'a t ->
  'b Lwd.t

Observe the content of a table by mapping and reducing it

val iter : ('a -> unit) -> 'a t -> unit

Immediate, non reactive, iteration over elements of a table