links

The Links Programming Language
IN THIS PACKAGE
include Notfound.Map.S with type key = string
type key = string

The type of the map keys.

type !+'a t

The type of maps from type key to type 'a.

val empty : 'a t

The empty map.

val is_empty : 'a t -> bool

Test whether a map is empty or not.

val mem : key -> 'a t -> bool

mem x m returns true if m contains a binding for x, and false otherwise.

val add : key -> 'a -> 'a t -> 'a t

add key data m returns a map containing the same bindings as m, plus a binding of key to data. If key was already bound in m to a value that is physically equal to data, m is returned unchanged (the result of the function is then physically equal to m). Otherwise, the previous binding of key in m disappears.

  • before 4.03

    Physical equality was not ensured.

val update : key -> ( 'a option -> 'a option ) -> 'a t -> 'a t

update key f m returns a map containing the same bindings as m, except for the binding of key. Depending on the value of y where y is f (find_opt key m), the binding of key is added, removed or updated. If y is None, the binding is removed if it exists; otherwise, if y is Some z then key is associated to z in the resulting map. If key was already bound in m to a value that is physically equal to z, m is returned unchanged (the result of the function is then physically equal to m).

  • since 4.06.0
val singleton : key -> 'a -> 'a t

singleton x y returns the one-element map that contains a binding y for x.

  • since 3.12.0
val remove : key -> 'a t -> 'a t

remove x m returns a map containing the same bindings as m, except for x which is unbound in the returned map. If x was not in m, m is returned unchanged (the result of the function is then physically equal to m).

  • before 4.03

    Physical equality was not ensured.

val merge : ( key -> 'a option -> 'b option -> 'c option ) -> 'a t -> 'b t -> 'c t

merge f m1 m2 computes a map whose keys are a subset of the keys of m1 and of m2. The presence of each such binding, and the corresponding value, is determined with the function f. In terms of the find_opt operation, we have find_opt x (merge f m1 m2) = f x (find_opt x m1) (find_opt x m2) for any key x, provided that f x None None = None.

  • since 3.12.0
val union : ( key -> 'a -> 'a -> 'a option ) -> 'a t -> 'a t -> 'a t

union f m1 m2 computes a map whose keys are a subset of the keys of m1 and of m2. When the same binding is defined in both arguments, the function f is used to combine them. This is a special case of merge: union f m1 m2 is equivalent to merge f' m1 m2, where

  • f' _key None None = None
  • f' _key (Some v) None = Some v
  • f' _key None (Some v) = Some v
  • f' key (Some v1) (Some v2) = f key v1 v2
  • since 4.03.0
val compare : ( 'a -> 'a -> int ) -> 'a t -> 'a t -> int

Total ordering between maps. The first argument is a total ordering used to compare data associated with equal keys in the two maps.

val equal : ( 'a -> 'a -> bool ) -> 'a t -> 'a t -> bool

equal cmp m1 m2 tests whether the maps m1 and m2 are equal, that is, contain equal keys and associate them with equal data. cmp is the equality predicate used to compare the data associated with the keys.

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

iter f m applies f to all bindings in map m. f receives the key as first argument, and the associated value as second argument. The bindings are passed to f in increasing order with respect to the ordering over the type of the keys.

val fold : ( key -> 'a -> 'b -> 'b ) -> 'a t -> 'b -> 'b

fold f m init computes (f kN dN ... (f k1 d1 init)...), where k1 ... kN are the keys of all bindings in m (in increasing order), and d1 ... dN are the associated data.

val for_all : ( key -> 'a -> bool ) -> 'a t -> bool

for_all f m checks if all the bindings of the map satisfy the predicate f.

  • since 3.12.0
val exists : ( key -> 'a -> bool ) -> 'a t -> bool

exists f m checks if at least one binding of the map satisfies the predicate f.

  • since 3.12.0
val cardinal : 'a t -> int

Return the number of bindings of a map.

  • since 3.12.0
val bindings : 'a t -> (key * 'a) list

Return the list of all bindings of the given map. The returned list is sorted in increasing order of keys with respect to the ordering Ord.compare, where Ord is the argument given to Stdlib.Map.Make.

  • since 3.12.0
val min_binding : 'a t -> key * 'a

Return the binding with the smallest key in a given map (with respect to the Ord.compare ordering), or raise Not_found if the map is empty.

  • since 3.12.0
val min_binding_opt : 'a t -> (key * 'a) option

Return the binding with the smallest key in the given map (with respect to the Ord.compare ordering), or None if the map is empty.

  • since 4.05
val max_binding : 'a t -> key * 'a

Same as min_binding, but returns the binding with the largest key in the given map.

  • since 3.12.0
val max_binding_opt : 'a t -> (key * 'a) option

Same as min_binding_opt, but returns the binding with the largest key in the given map.

  • since 4.05
val choose : 'a t -> key * 'a

Return one binding of the given map, or raise Not_found if the map is empty. Which binding is chosen is unspecified, but equal bindings will be chosen for equal maps.

  • since 3.12.0
val choose_opt : 'a t -> (key * 'a) option

Return one binding of the given map, or None if the map is empty. Which binding is chosen is unspecified, but equal bindings will be chosen for equal maps.

  • since 4.05
val split : key -> 'a t -> 'a t * 'a option * 'a t

split x m returns a triple (l, data, r), where l is the map with all the bindings of m whose key is strictly less than x; r is the map with all the bindings of m whose key is strictly greater than x; data is None if m contains no binding for x, or Some v if m binds v to x.

  • since 3.12.0
val find : key -> 'a t -> 'a

find x m returns the current value of x in m, or raises Not_found if no binding for x exists.

val find_opt : key -> 'a t -> 'a option

find_opt x m returns Some v if the current value of x in m is v, or None if no binding for x exists.

  • since 4.05
val find_first : ( key -> bool ) -> 'a t -> key * 'a

find_first f m, where f is a monotonically increasing function, returns the binding of m with the lowest key k such that f k, or raises Not_found if no such key exists.

For example, find_first (fun k -> Ord.compare k x >= 0) m will return the first binding k, v of m where Ord.compare k x >= 0 (intuitively: k >= x), or raise Not_found if x is greater than any element of m.

  • since 4.05
val find_first_opt : ( key -> bool ) -> 'a t -> (key * 'a) option

find_first_opt f m, where f is a monotonically increasing function, returns an option containing the binding of m with the lowest key k such that f k, or None if no such key exists.

  • since 4.05
val find_last : ( key -> bool ) -> 'a t -> key * 'a

find_last f m, where f is a monotonically decreasing function, returns the binding of m with the highest key k such that f k, or raises Not_found if no such key exists.

  • since 4.05
val find_last_opt : ( key -> bool ) -> 'a t -> (key * 'a) option

find_last_opt f m, where f is a monotonically decreasing function, returns an option containing the binding of m with the highest key k such that f k, or None if no such key exists.

  • since 4.05
val map : ( 'a -> 'b ) -> 'a t -> 'b t

map f m returns a map with same domain as m, where the associated value a of all bindings of m has been replaced by the result of the application of f to a. The bindings are passed to f in increasing order with respect to the ordering over the type of the keys.

val mapi : ( key -> 'a -> 'b ) -> 'a t -> 'b t

Same as map, but the function receives as arguments both the key and the associated value for each binding of the map.

Maps and Sequences

val to_seq : 'a t -> (key * 'a) Seq.t

Iterate on the whole map, in ascending order of keys

  • since 4.07
val to_rev_seq : 'a t -> (key * 'a) Seq.t

Iterate on the whole map, in descending order of keys

  • since 4.12
val to_seq_from : key -> 'a t -> (key * 'a) Seq.t

to_seq_from k m iterates on a subset of the bindings of m, in ascending order of keys, from key k or above.

  • since 4.07
val add_seq : (key * 'a) Seq.t -> 'a t -> 'a t

Add the given bindings to the map, in order.

  • since 4.07
val of_seq : (key * 'a) Seq.t -> 'a t

Build a map from the given bindings

  • since 4.07
exception Not_disjoint of key * string
val filterv : ( 'a -> bool ) -> 'a t -> 'a t

filter by value

val size : 'a t -> int

the number of distinct keys in the map

val to_alist : 'a t -> (key * 'a) list

convert the map to an association list

val from_alist : (key * 'a) list -> 'a t

construct a map from an association list

val to_list : ( key -> 'a -> 'b ) -> 'a t -> 'b list

construct a list from a map

val megamap : ( (key * 'a) -> key * 'b ) -> 'a t -> 'b t
val pop : key -> 'a t -> 'a * 'a t

remove the item with the given key from the map and return the remainder.

val lookup : key -> 'a t -> 'a option

remove the item with the given key from the map and return the remainder.

as `find', but return an option instead of raising an exception

val union_disjoint : 'a t -> 'a t -> 'a t

disjoint union

val union_all : 'a t list -> 'a t

disjoint union of a list of maps

val superimpose : 'a t -> 'a t -> 'a t

Extend the second map with the first

val split_paired : ('a * 'b) t -> 'a t * 'b t

split a pair map into a pair of maps

val partition : ( key -> 'a -> bool ) -> 'a t -> 'a t * 'a t

divide the map by a predicate

val filter : ( key -> 'a -> bool ) -> 'a t -> 'a t

filters using both keys and values

val filter_map : ( key -> 'a -> 'b option ) -> 'a t -> 'b t

filters and applies a function -- None values discarded

val show : ( Format.formatter -> 'a -> unit ) -> 'a t -> string
val pp : ( Format.formatter -> 'a -> unit ) -> Format.formatter -> 'a t -> unit