Make2.Seq
The Monad.Collection.S2 interface for sequences
all cs
performs all computations in cs
and returns a list of results in the same order. The order of evaluation is unspecified.
all_ignore cs
performs all computations in cs
in an unspecified order, and discards the results.
sequence cs
performs all computations in cs
from left to right.
val map :
'a Core_kernel.Sequence.t ->
f:('a -> ('b, 'e) T2(M).t) ->
('b Core_kernel.Sequence.t, 'e) T2(M).t
map xs ~f
returns a container where n
'th element is a result of computation f x_n
, where x_n
is the n
'th element of the input container. It is unspecified, in which order the computations are evaluated, and whether all computations are performed.
iter xs ~f
performs f x
for each x
in xs
in the left to right order.
val fold :
'a Core_kernel.Sequence.t ->
init:'b ->
f:('b -> 'a -> ('b, 'e) T2(M).t) ->
('b, 'e) T2(M).t
fold xs ~init:s0 ~f
folds f
over xs
in the given monad.
Effectively computes a chain:
f s0 x0 >>= fun s1 -> f s1 x1 >>= fun s2 -> ... f sN xN
Except that the computation uses a constant stack size.
val fold_left :
'a Core_kernel.Sequence.t ->
init:'b ->
f:('b -> 'a -> ('b, 'e) T2(M).t) ->
('b, 'e) T2(M).t
fold_left
is a synonym for fold
.
val fold_right :
'a Core_kernel.Sequence.t ->
f:('a -> 'b -> ('b, 'e) T2(M).t) ->
init:'b ->
('b, 'e) T2(M).t
fold_right xs ~f ~init:s0
folds f
over xs
from right to left in the given monad.
Effectively computes a chain:
f x_N s0 >>= fun s1 -> f x_(N-1) s1 >>= fun s2 -> ... f x0 s_N
Except that the computation uses a constant stack size.
val reduce :
'a Core_kernel.Sequence.t ->
f:('a -> 'a -> ('a, 'e) T2(M).t) ->
('a option, 'e) T2(M).t
reduce xs ~f
same as fold
except that the initial state is obtained from the first element of the container, i.e., computes a sequence
f x0 x1 >>= fun s1 -> f s1 x2 >>= fun s2 -> ... f sN xN
exists xs ~f
returns a computation that results in true
iff there exists an element x
in xs
such that f x
evaluates to true
for_all xs ~f
returns a computation that results in true
iff for all x
in xs
f x
evaluates to true
.
count xs ~f
returns a computation that results to a number of elements of xs
for which f
evaluates to true
. The order of application of f
is unspecified.
val map_reduce :
(module Monoid.S with type t = 'a) ->
'b Core_kernel.Sequence.t ->
f:('b -> ('a, 'e) T2(M).t) ->
('a, 'e) T2(M).t
map_reduce (module Monoid) xs ~f
a composition of map
and reduce
. Effectively the same as map xs ~f
and then reduce in Monoid
except that no intermediate collections are created.
find xs ~f
returns the first element x
of xs
for which f x
evaluates to true
.
val find_map :
'a Core_kernel.Sequence.t ->
f:('a -> ('b option, 'e) T2(M).t) ->
('b option, 'e) T2(M).t
find_map xs ~f
returns the first computation f x
for x
in xs
which will result in non None
.