Stack (melange.Stdlib.Stack)

Unsynchronized accesses

Unsynchronized accesses to a stack may lead to an invalid queue state. Thus, concurrent accesses to stacks must be synchronized (for instance with a Mutex.t).

type t(!'a);

The type of stacks containing elements of type 'a.

exception Empty;

Raised when Stack.pop or Stack.top is applied to an empty stack.

let create: unit => t('a);

Return a new stack, initially empty.

let push: 'a => t('a) => unit;

push x s adds the element x at the top of stack s.

let pop: t('a) => 'a;

pop s removes and returns the topmost element in stack s, or raises Empty if the stack is empty.

let pop_opt: t('a) => option('a);

pop_opt s removes and returns the topmost element in stack s, or returns None if the stack is empty.

since 4.08

let drop: t('a) => unit;

drop s removes the topmost element in stack s, or raises Empty if the stack is empty.

since 5.1

let top: t('a) => 'a;

top s returns the topmost element in stack s, or raises Empty if the stack is empty.

let top_opt: t('a) => option('a);

top_opt s returns the topmost element in stack s, or None if the stack is empty.

since 4.08

let clear: t('a) => unit;

Discard all elements from a stack.

let copy: t('a) => t('a);

Return a copy of the given stack.

let is_empty: t('a) => bool;

Return true if the given stack is empty, false otherwise.

let length: t('a) => int;

Return the number of elements in a stack. Time complexity O(1)

let iter: ('a => unit) => t('a) => unit;

iter f s applies f in turn to all elements of s, from the element at the top of the stack to the element at the bottom of the stack. The stack itself is unchanged.

let fold: ('acc => 'a => 'acc) => 'acc => t('a) => 'acc;

fold f accu s is (f (... (f (f accu x1) x2) ...) xn) where x1 is the top of the stack, x2 the second element, and xn the bottom element. The stack is unchanged.

since 4.03

Stacks and Sequences

let to_seq: t('a) => Seq.t('a);

Iterate on the stack, top to bottom. It is safe to modify the stack during iteration.

since 4.07

let add_seq: t('a) => Seq.t('a) => unit;

Add the elements from the sequence on the top of the stack.

since 4.07

let of_seq: Seq.t('a) => t('a);

Create a stack from the sequence.

since 4.07