Stack

Class Stack<X> provides a minimal LIFO stack of elements of type X.

See library Deque for mixed LIFO/FIFO behavior.

Example:

motoko name=initialize
import Stack "mo:base/Stack";

let stack = Stack.Stack<Nat>(); // create a stack

| Runtime | Space | |-----------|-----------| | O(1) | O(1) |

class Stack<T>()

public func push(x : T)

Push an element on the top of the stack.

Example:

motoko include=initialize
stack.push(1);
stack.push(2);
stack.push(3);
stack.peek(); // examine the top most element

| Runtime | Space | |-----------|-----------| | O(1) | O(1) |

public func isEmpty() : Bool

True when the stack is empty and false otherwise.

Example:

motoko include=initialize
stack.isEmpty();

| Runtime | Space | |-----------|-----------| | O(1) | O(1) |

public func peek() : ?T

Return (without removing) the top element, or return null if the stack is empty.

Example:

motoko include=initialize
stack.push(1);
stack.push(2);
stack.push(3);
stack.peek();

| Runtime | Space | |-----------|-----------| | O(1) | O(1) |

public func pop() : ?T

Remove and return the top element, or return null if the stack is empty.

Example:

motoko include=initialize
stack.push(1);
ignore stack.pop();
stack.isEmpty();

| Runtime | Space | |-----------|-----------| | O(1) | O(1) |