.TH "Weak.Make" 3o 2023-09-18 OCamldoc "OCaml library"
.SH NAME
Weak.Make \- Functor building an implementation of the weak hash set structure.
.SH Module
Module   Weak.Make
.SH Documentation
.sp
Module
.BI "Make"
 : 
.B functor (H : Hashtbl.HashedType) -> sig end

.sp
Functor building an implementation of the weak hash set structure\&.
.ft B
H\&.equal
.ft R
can\&'t be the physical equality, since only shallow
copies of the elements in the set are given to it\&.

.sp
.B "Parameters:"
.sp
"H"

.B Stdlib.Hashtbl.HashedType





.sp
.sp
.I type data 

.sp
The type of the elements stored in the table\&.

.sp
.I type t 

.sp
The type of tables that contain elements of type 
.ft B
data
.ft R
\&.
Note that weak hash sets cannot be marshaled using
.ft B
output_value
.ft R
or the functions of the 
.ft B
Marshal
.ft R
module\&.

.sp

.I val create 
: 
.B int -> t
.sp

.ft B
create n
.ft R
creates a new empty weak hash set, of initial
size 
.ft B
n
.ft R
\&.  The table will grow as needed\&.

.sp

.I val clear 
: 
.B t -> unit
.sp
Remove all elements from the table\&.

.sp

.I val merge 
: 
.B t -> data -> data
.sp

.ft B
merge t x
.ft R
returns an instance of 
.ft B
x
.ft R
found in 
.ft B
t
.ft R
if any,
or else adds 
.ft B
x
.ft R
to 
.ft B
t
.ft R
and return 
.ft B
x
.ft R
\&.

.sp

.I val add 
: 
.B t -> data -> unit
.sp

.ft B
add t x
.ft R
adds 
.ft B
x
.ft R
to 
.ft B
t
.ft R
\&.  If there is already an instance
of 
.ft B
x
.ft R
in 
.ft B
t
.ft R
, it is unspecified which one will be
returned by subsequent calls to 
.ft B
find
.ft R
and 
.ft B
merge
.ft R
\&.

.sp

.I val remove 
: 
.B t -> data -> unit
.sp

.ft B
remove t x
.ft R
removes from 
.ft B
t
.ft R
one instance of 
.ft B
x
.ft R
\&.  Does
nothing if there is no instance of 
.ft B
x
.ft R
in 
.ft B
t
.ft R
\&.

.sp

.I val find 
: 
.B t -> data -> data
.sp

.ft B
find t x
.ft R
returns an instance of 
.ft B
x
.ft R
found in 
.ft B
t
.ft R
\&.

.sp
.B "Raises Not_found"
if there is no such element\&.

.sp

.I val find_opt 
: 
.B t -> data -> data option
.sp

.ft B
find_opt t x
.ft R
returns an instance of 
.ft B
x
.ft R
found in 
.ft B
t
.ft R
or 
.ft B
None
.ft R
if there is no such element\&.

.sp
.B "Since"
4.05

.sp

.I val find_all 
: 
.B t -> data -> data list
.sp

.ft B
find_all t x
.ft R
returns a list of all the instances of 
.ft B
x
.ft R
found in 
.ft B
t
.ft R
\&.

.sp

.I val mem 
: 
.B t -> data -> bool
.sp

.ft B
mem t x
.ft R
returns 
.ft B
true
.ft R
if there is at least one instance
of 
.ft B
x
.ft R
in 
.ft B
t
.ft R
, false otherwise\&.

.sp

.I val iter 
: 
.B (data -> unit) -> t -> unit
.sp

.ft B
iter f t
.ft R
calls 
.ft B
f
.ft R
on each element of 
.ft B
t
.ft R
, in some unspecified
order\&.  It is not specified what happens if 
.ft B
f
.ft R
tries to change
.ft B
t
.ft R
itself\&.

.sp

.I val fold 
: 
.B (data -> 'a -> 'a) -> t -> 'a -> 'a
.sp

.ft B
fold f t init
.ft R
computes 
.ft B
(f d1 (\&.\&.\&. (f dN init)))
.ft R
where
.ft B
d1 \&.\&.\&. dN
.ft R
are the elements of 
.ft B
t
.ft R
in some unspecified order\&.
It is not specified what happens if 
.ft B
f
.ft R
tries to change 
.ft B
t
.ft R
itself\&.

.sp

.I val count 
: 
.B t -> int
.sp
Count the number of elements in the table\&.  
.ft B
count t
.ft R
gives the
same result as 
.ft B
fold (fun _ n \-> n+1) t 0
.ft R
but does not delay the
deallocation of the dead elements\&.

.sp

.I val stats 
: 
.B t -> int * int * int * int * int * int
.sp
Return statistics on the table\&.  The numbers are, in order:
table length, number of entries, sum of bucket lengths,
smallest bucket length, median bucket length, biggest bucket length\&.

.sp