Provided by: ocaml-man_4.13.1-4ubuntu1_all 
NAME
Map.S - Output signature of the functor Map.Make.
Module type
Module type Map.S
Documentation
Module type S
= sig end
Output signature of the functor Map.Make .
type key
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.
Before4.03 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 ).
Before4.03 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 filter : (key -> 'a -> bool) -> 'a t -> 'a t
filter f m returns the map with all the bindings in m that satisfy predicate p . If every
binding in m satisfies f , m is returned unchanged (the result of the function is then
physically equal to m )
Before4.03 Physical equality was not ensured.
Since 3.12.0
val filter_map : (key -> 'a -> 'b option) -> 'a t -> 'b t
filter_map f m applies the function f to every binding of m , and builds a map from the
results. For each binding (k, v) in the input map:
-if f k v is None then k is not in the result,
-if f k v is Some v' then the binding (k, v') is in the output map.
For example, the following function on maps whose values are lists
filter_map
(fun _k li -> match li with [] -> None | _::tl -> Some tl)
m
drops all bindings of m whose value is an empty list, and pops the first element of each
value that is non-empty.
Since 4.11.0
val partition : (key -> 'a -> bool) -> 'a t -> 'a t * 'a t
partition f m returns a pair of maps (m1, m2) , where m1 contains all the bindings of m
that satisfy the predicate f , and m2 is the map with all the bindings of m that do not
satisfy 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 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 Map.S.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 Map.S.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.S.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