keen/col/stack

stack[t] record (has private fields)

Immutable stack type. Iterates from the bottom (least recently pushed) to the top (most recently pushed).

list-new[t] t stack(a t[])

The first element of a goes on the bottom and the last element of a goes on the top.

to[t] t stack(a t[])

Stack containing the given elements. The first element of a goes on the bottom and the last element of a goes on the top.

to[t] t[](a t stack)

is-empty[t] bool(a t stack)

true if a.size == 0.

~[t] t stack(a t stack, b t)

Appends an element to the stack. This is O(1).

size[t] nat64(a t stack)

Number of elements in the stack. This is O(1).

peek[t] t option(a t stack)

Top element. Returns an empty option if a is-empty. This is O(1).

pop[t] (t stack, t) option(a t stack)

Returns the top element of the a stacknd a new stack with all elements but the top. Returns an empty option if a is-empty.

some[t] bool(a t stack, f bool mut(t))

some-reverse[t] bool(a t stack, f bool mut(t))