Library
Module
Module type
Parameter
Class
Class type
String maps.
include Map.S with type key := string
val empty : 'a t
The empty map.
val is_empty : 'a t -> bool
Test whether a map is empty or not.
val mem : string -> 'a t -> bool
mem x m
returns true
if m
contains a binding for x
, and false
otherwise.
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.
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
).
val singleton : string -> 'a -> 'a t
singleton x y
returns the one-element map that contains a binding y
for x
.
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
).
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
.
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
Total ordering between maps. The first argument is a total ordering used to compare data associated with equal keys in the two maps.
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 : (string -> '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 : (string -> '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 : (string -> 'a -> bool) -> 'a t -> bool
for_all f m
checks if all the bindings of the map satisfy the predicate f
.
val exists : (string -> 'a -> bool) -> 'a t -> bool
exists f m
checks if at least one binding of the map satisfies the predicate f
.
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
)
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:
f k v
is None
then k
is not in the result,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.
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
.
val cardinal : 'a t -> int
Return the number of bindings of a map.
val bindings : 'a t -> (string * '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 Make
.
val min_binding_opt : 'a t -> (string * '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.
val max_binding_opt : 'a t -> (string * 'a) option
Same as S.min_binding_opt
, but returns the binding with the largest key in the given map.
val choose_opt : 'a t -> (string * '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.
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
.
val find_opt : string -> '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.
val find_first : (string -> bool) -> 'a t -> string * '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
.
val find_first_opt : (string -> bool) -> 'a t -> (string * '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.
val find_last : (string -> bool) -> 'a t -> string * '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.
val find_last_opt : (string -> bool) -> 'a t -> (string * '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.
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.
Same as S.map
, but the function receives as arguments both the key and the associated value for each binding of the map.
to_seq_from k m
iterates on a subset of the bindings of m
, in ascending order of keys, from key k
or above.
val min_binding : 'a t -> (string * 'a) option
Exception safe Map.S.min_binding
.
val get_min_binding : 'a t -> string * 'a
get_min_binding
is like min_binding
but
val max_binding : 'a t -> (string * 'a) option
Exception safe Map.S.max_binding
.
val get_max_binding : 'a t -> string * 'a
get_max_binding
is like max_binding
but
val choose : 'a t -> (string * 'a) option
Exception safe Map.S.choose
.
val find : string -> 'a t -> 'a option
Exception safe Map.S.find
.
val get : string -> 'a t -> 'a
get k m
is like Map.S.find
but raises Invalid_argument
if k
is not bound in m
.
val of_list : (string * 'a) list -> 'a t
of_list bs
is List.fold_left (fun m (k, v) -> add k v m) empty
bs
.
val of_stdlib_map : 'a Map.Make(String).t -> 'a t
of_stdlib_map m
is a map from the stdlib-compatible map m
.
val to_stdlib_map : 'a t -> 'a Map.Make(String).t
to_stdlib_map m
is the stdlib-compatible map equivalent to m
.
val pp :
?sep:(Format.formatter -> unit -> unit) ->
(Format.formatter -> (string * 'a) -> unit) ->
Format.formatter ->
'a t ->
unit
pp ~sep pp_binding ppf m
formats the bindings of m
on ppf
. Each binding is formatted with pp_binding
and bindings are separated by sep
(defaults to Format.pp_print_cut
). If the map is empty leaves ppf
untouched.
val dump : (Format.formatter -> 'a -> unit) -> Format.formatter -> 'a t -> unit
dump pp_v ppf m
prints an unspecified representation of m
on ppf
using pp_v
to print the map codomain elements.
val dump_string_map : Format.formatter -> string t -> unit
dump_string_map ppf m
prints an unspecified representation of the string map m
on ppf
.