module BatMap:sig
..end
Association tables over ordered types.
This module implements applicative association tables, also known as finite maps or dictionaries, given a total ordering function over the keys. All operations over maps are purely applicative (no side-effects). The implementation uses balanced binary trees, and therefore searching and insertion take time logarithmic in the size of the map.
Note OCaml, Batteries Included, provides two implementations of
maps: polymorphic maps and functorized maps. Functorized maps (see
BatMap.S
and BatMap.Make
) are slightly more complex to use but offer
stronger type-safety. Polymorphic maps make it easier to shoot
yourself in the foot. In case of doubt, you should use functorized
maps.
The important part is the BatMap.Make
module which builds association
maps from a user-provided datatype and comparison function. In the
BatMap.Make
module (or its output signature BatMap.S
) are documentated all
functions available on maps.
Here is a typical example of use:
module MyKeyType = struct
type t = my_type
let compare = my_compare_function
end
module MyMap = Map.Make(MyKeyType)
let some_map = MyMap.add something MyMap.empty
...
To define maps with integer/string keys:
module IntMap = Map.Make(Int)
module StringMap = Map.Make(String)
module type S =sig
..end
module Make:
Functor building an implementation of the map structure given a totally ordered type.
*
module Int:S
with type key = int
module Int32:S
with type key = int32
module Int64:S
with type key = int64
module Nativeint:S
with type key = nativeint
module Float:S
with type key = float
module Char:S
with type key = char
module String:S
with type key = string
The functions below present the manipulation of polymorphic maps, as were provided by the Extlib PMap module.
They are similar in functionality to the functorized BatMap.Make
module, but only uses the Pervasives.compare
function to compare
elements. If you need to compare using a custom comparison
function, it is recommended to use the functorized maps provided
by BatMap.Make
.
type (+'a, +'b)
t
val empty : ('a, 'b) t
The empty map, using compare
as key comparison function.
val is_empty : ('a, 'b) t -> bool
Returns true
if the map is empty.
val singleton : 'a -> 'b -> ('a, 'b) t
Creates a new map with a single binding.
val cardinal : ('a, 'b) t -> int
Return the number of bindings of a map.
val add : 'a -> 'b -> ('a, 'b) t -> ('a, 'b) t
add x y m
returns a map containing the same bindings as
m
, plus a binding of x
to y
. If x
was already bound
in m
, its previous binding disappears.
If x
was already bound to some z
that is physically equal
to y
, then the returned map is physically equal to m
.
val update : 'a -> 'a -> 'b -> ('a, 'b) t -> ('a, 'b) t
update k1 k2 v2 m
replace the previous binding of k1
in m
by
k2
associated to v2
.
This is equivalent to add k2 v2 (remove k1) m
, but more efficient
in the case where k1
and k2
have the same key ordering.
If k1
and k2
have the same key ordering and v2
is physically
equal to the value k1
is bound to in m
then the returned map will
be physically equal to m
Not_found
if k1
is not bound in m
.val update_stdlib : 'a -> ('b option -> 'b option) -> ('a, 'b) t -> ('a, 'b) t
update_stdlib k f m
returns a map containing the same bindings as m
,
except k
has a new binding as determined by f
:
First, calculate y
as f (find_opt k m)
.
If y = Some v
then k
will be bound to v
in the resulting map.
Else k
will not be bound in the resulting map.
If v
is physically equal to the value of the previous binding of k
in m
,
then the returned map will be physically equal to m
.
This function does the same thing as update
in the stdlib, but has a
different name for backwards compatibility reasons.
val find : 'a -> ('a, 'b) t -> 'b
find x m
returns the current binding of x
in m
,
or raises Not_found
if no such binding exists.
val find_opt : 'a -> ('a, 'b) t -> 'b option
find_opt x m
returns Some b where b is the current binding
* of x
in m
, or None if no such binding exists.
val find_default : 'b -> 'a -> ('a, 'b) t -> 'b
find_default d x m
returns the current binding of x
in m
,
or the default value d
if no such binding exists.
val find_first : ('a -> bool) -> ('a, 'b) t -> 'a * 'b
find_first f m
returns the first binding (k, v)
for which f k
is true
or raises Not_found
if there is no such binding.
f
must be monotonically increasing,
i.e. if k1 < k2 && f k1
is true then f k2
must also be true.
val find_first_opt : ('a -> bool) -> ('a, 'b) t -> ('a * 'b) option
find_first_opt f m
returns Some (k, v)
for the first binding (k, v)
for which f k
is true or returns None
if there is no such binding.
f
must be monotonically increasing,
i.e. if k1 < k2 && f k1
is true then f k2
must also be true.
val find_last : ('a -> bool) -> ('a, 'b) t -> 'a * 'b
find_last f m
returns the last binding (k, v)
for which f k
is true
or raises Not_found
if there is no such binding.
f
must be monotonically decreasing,
i.e. if k1 < k2 && f k2
is true then f k1
must also be true.
val find_last_opt : ('a -> bool) -> ('a, 'b) t -> ('a * 'b) option
find_last_opt f m
returns Some (k, v)
for the last binding (k, v)
for which f k
is true or returns None
if there is no such binding.
f
must be monotonically decreasing,
i.e. if k1 < k2 && f k2
is true then f k1
must also be true.
val remove : 'a -> ('a, 'b) t -> ('a, 'b) t
remove x m
returns a map containing the same bindings as
m
, except for x
which is unbound in the returned map.
The returned map is physically equal to the passed one if x
was
already unbound.
val remove_exn : 'a -> ('a, 'b) t -> ('a, 'b) t
remove_exn x m
behaves like remove x m
except that it raises
an exception if x
is unbound in m
.
Not_found
if x
is unbound in m
val mem : 'a -> ('a, 'b) t -> bool
mem x m
returns true
if m
contains a binding for x
,
and false
otherwise.
val iter : ('a -> 'b -> unit) -> ('a, 'b) 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 order in which the bindings are passed to
f
is unspecified. Only current bindings are presented to f
:
bindings hidden by more recent bindings are not passed to f
.
val map : ('b -> 'c) -> ('a, 'b) t -> ('a, 'c) 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 order in which the associated values are passed to f
is unspecified.
val mapi : ('a -> 'b -> 'c) -> ('a, 'b) t -> ('a, 'c) t
Same as map
, but the function receives as arguments both the
key and the associated value for each binding of the map.
val fold : ('b -> 'c -> 'c) -> ('a, 'b) t -> 'c -> 'c
fold f m a
computes (f kN dN ... (f k1 d1 (f k0 d0 a))...)
,
where k0,k1..kN
are the keys of all bindings in m
,
and d0,d1..dN
are the associated data.
The order in which the bindings are presented to f
is
unspecified.
val foldi : ('a -> 'b -> 'c -> 'c) -> ('a, 'b) t -> 'c -> 'c
Same as fold
, but the function receives as arguments both the
key and the associated value for each binding of the map.
val at_rank_exn : int -> ('key, 'a) t -> 'key * 'a
at_rank_exn i m
returns the (key,value)
pair
whose key is at rank i
in m
,
that is the i
-th element in increasing order of the keys
(the 0
-th element being the smallest key in m
with its
associated value).
Not_found
if m = empty
.Invalid_argument
error_message if i < 0 || i >= cardinal m
val filterv : ('a -> bool) -> ('key, 'a) t -> ('key, 'a) t
filterv f m
returns a map where only the values a
of m
such that f a = true
remain. The bindings are passed to f
in increasing order with respect to the ordering over the
type of the keys.
val filter : ('key -> 'a -> bool) -> ('key, 'a) t -> ('key, 'a) t
filter f m
returns a map where only the (key, value)
pairs of m
such that f key value = true
remain. The bindings are passed to
f
in increasing order with respect to the ordering over the type
of the keys.
If f
returns true
for all bindings of m
the returned map is physically
equal to m
.
val filter_map : ('key -> 'a -> 'b option) -> ('key, 'a) t -> ('key, 'b) t
filter_map f m
combines the features of filter
and
map
. It calls calls f key0 a0
, f key1 a1
, f keyn an
where a0..an
are the elements of m
and key0..keyn
the
respective corresponding keys. It returns the map of
(keyi, bi)
pairs such as f keyi ai = Some bi
(when f
returns
None
, the corresponding element of m
is discarded).
val choose : ('key, 'a) t -> 'key * 'a
Return one binding of the given map. Which binding is chosen is unspecified, but equal bindings will be chosen for equal maps.
Not_found
if the map is emptyval choose_opt : ('key, 'a) t -> ('key * 'a) option
Return Some (k, v)
for one binding (k, v)
of the given map,
if the map is not empty. Else, return None.
Which binding is chosen is unspecified, but equal bindings will be
chosen for equal maps.
val any : ('key, 'a) t -> 'key * 'a
Return one binding of the given map. The difference with choose is that there is no guarantee that equals elements will be picked for equal sets. This merely returns the quickest binding to get (O(1)).
Not_found
if the map is empty.val split : 'key ->
('key, 'a) t -> ('key, 'a) t * 'a option * ('key, '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
.
val min_binding : ('key, 'a) t -> 'key * 'a
Returns the binding with the smallest key. Raises Not_found if the map is empty.
val min_binding_opt : ('key, 'a) t -> ('key * 'a) option
Return Some (key, value)
for the key, value
pair with
the smallest key, or None
if the map is empty.
val pop_min_binding : ('key, 'a) t -> ('key * 'a) * ('key, 'a) t
Returns the binding with the smallest key along with the rest of the map.
val max_binding : ('key, 'a) t -> 'key * 'a
Return the (key, value)
pair with the largest key.
Raises Not_found if the map is empty.
val max_binding_opt : ('key, 'a) t -> ('key * 'a) option
Return Some (key, value)
for the key, value
pair with
the largest key, or None
if the map is empty.
val pop_max_binding : ('key, 'a) t -> ('key * 'a) * ('key, 'a) t
Returns the binding with the largest key along with the rest of the map.
val enum : ('a, 'b) t -> ('a * 'b) BatEnum.t
Creates an enumeration for this map, enumerating (key, value)
pairs
with the keys in increasing order.
val backwards : ('a, 'b) t -> ('a * 'b) BatEnum.t
Creates an enumeration for this map, enumerating (key, value)
pairs
with the keys in decreasing order.
val keys : ('a, 'b) t -> 'a BatEnum.t
Return an enumeration of all the keys of a map.
val values : ('a, 'b) t -> 'b BatEnum.t
Return an enumeration of all the values of a map.
val of_enum : ('a * 'b) BatEnum.t -> ('a, 'b) t
Creates a map from an enumeration.
val for_all : ('a -> 'b -> bool) -> ('a, 'b) t -> bool
Tests whether all (key, value)
pairs satisfy a predicate function.
val exists : ('a -> 'b -> bool) -> ('a, 'b) t -> bool
Tests whether some (key, value)
pair satisfies a predicate function.
val partition : ('a -> 'b -> bool) ->
('a, 'b) t -> ('a, 'b) t * ('a, 'b) t
partition p m
returns a pair of maps (m1, m2)
, where m1
contains all the bindings of s
that satisfy the predicate
p
, and m2
is the map with all the bindings of s
that do
not satisfy p
.
val add_carry : 'a -> 'b -> ('a, 'b) t -> ('a, 'b) t * 'b option
add_carry k v m
adds the binding (k, v)
to m
, returning the new
map and optionally the previous value bound to k
.
val modify : 'a -> ('b -> 'b) -> ('a, 'b) t -> ('a, 'b) t
modify k f m
replaces the previous binding for k
with f
applied to that value. If k
is unbound in m
or Not_found
is
raised during the search, Not_found
is raised.
Not_found
if k
is unbound in m
(or f
raises Not_found
)val modify_def : 'b -> 'a -> ('b -> 'b) -> ('a, 'b) t -> ('a, 'b) t
modify_def v0 k f m
replaces the previous binding for k
with f
applied to that value. If k
is unbound in m
or
Not_found
is raised during the search, f v0
is
inserted (as if the value found were v0
).
val modify_opt : 'a -> ('b option -> 'b option) -> ('a, 'b) t -> ('a, 'b) t
modify_opt k f m
allow to modify the binding for k
in m
or absence thereof.
val extract : 'a -> ('a, 'b) t -> 'b * ('a, 'b) t
extract k m
removes the current binding of k
from m
,
returning the value k
was bound to and the updated m
.
val pop : ('a, 'b) t -> ('a * 'b) * ('a, 'b) t
pop m
returns a binding from m
and m
without that
binding.
val union : ('a, 'b) t -> ('a, 'b) t -> ('a, 'b) t
union m1 m2
merges two maps, using the comparison function of
m1
. In case of conflicted bindings, m2
's bindings override
m1
's. Equivalent to foldi add m2 m1
.
The resulting map uses the comparison function of m1
.
val union_stdlib : ('key -> 'a -> 'a -> 'a option) ->
('key, 'a) t -> ('key, 'a) t -> ('key, 'a) t
union_stdlib 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 function is similar to merge
, except f
is only called if a key
is present in both m1
and m2
. If a key is present in either m1
or m2
but not in both, it (and the corresponding value) will be
present in the resulting map.
This is the union method from the stdlib map, renamed for backwards compatibility.
val to_seq : ('key, 'a) t -> ('key * 'a) BatSeq.t
Iterate on the whole map, in ascending order of keys.
val to_rev_seq : ('key, 'a) t -> ('key * 'a) BatSeq.t
Iterate on the whole map, in descending order of keys.
val to_seq_from : 'key -> ('key, 'a) t -> ('key * 'a) BatSeq.t
to_seq_from k m
iterates on a subset of the bindings in m
,
namely those bindings greater or equal to k
, in ascending order.
val add_seq : ('key * 'a) BatSeq.t -> ('key, 'a) t -> ('key, 'a) t
add the given bindings to the map, in order.
val of_seq : ('key * 'a) BatSeq.t -> ('key, 'a) t
build a map from the given bindings
val diff : ('a, 'b) t -> ('a, 'b) t -> ('a, 'b) t
diff m1 m2
removes all bindings of keys found in m2
from m1
,
using the comparison function of m1
. Equivalent to
foldi (fun k _v m -> remove k m) m2 m1
.
The resulting map uses the comparison function of m1
.
val intersect : ('b -> 'c -> 'd) ->
('a, 'b) t -> ('a, 'c) t -> ('a, 'd) t
intersect merge_f m1 m2
returns a map with bindings only for
keys bound in both m1
and m2
, and with k
bound to merge_f
, where
v1 v2v1
and v2
are k
's bindings in m1
and m2
.
The resulting map uses the comparison function of m1
.
val merge : ('key -> 'a option -> 'b option -> 'c option) ->
('key, 'a) t -> ('key, 'b) t -> ('key, 'c) t
merge f m1 m2
computes a map whose keys is a subset of keys of m1
and of m2
. The presence of each such binding, and the corresponding
value, is determined with the function f
.
The resulting map uses the comparison function of m1
.
val compare : ('b -> 'b -> int) -> ('a, 'b) t -> ('a, 'b) t -> int
val equal : ('b -> 'b -> bool) -> ('a, 'b) t -> ('a, 'b) t -> bool
Construct a comparison or equality function for maps based on a value comparison or equality function. Uses the key comparison function to compare keys
module Exceptionless:sig
..end
Exceptionless versions of functions
module Infix:sig
..end
Infix operators over a BatPMap
val (-->) : ('a, 'b) t -> 'a -> 'b
Map find and insert from Infix
val (<--) : ('a, 'b) t -> 'a * 'b -> ('a, 'b) t
val bindings : ('key, 'a) t -> ('key * 'a) list
Return the list of all bindings of the given map. The returned list is sorted in increasing key order.
Added for compatibility with stdlib 3.12
val print : ?first:string ->
?last:string ->
?sep:string ->
?kvsep:string ->
('a BatInnerIO.output -> 'b -> unit) ->
('a BatInnerIO.output -> 'c -> unit) ->
'a BatInnerIO.output -> ('b, 'c) t -> unit
module PMap:sig
..end