Functional Stacks

Denys Duchier

module

x-oz://system/adt/Stack.ozf

This module provides a functional implementation of stacks

Exports

The module exports the following constructors:

{Stack.new ?S}

returns a new functional stack instance S, currently empty

{Stack.newFromList +L ?S}

returns a new functional stack instance S initialized with the elements of list L

Instance API

Each functional stack instance S has the following features:

{S.get ?V}

returns the next value V available from S, or raises exception empty if none

{S.put +V}

pushes a new value V onto the stack

{S.getPut ?Old +New}

atomically, gets the next value Old available from S and pushes the value New. If S was empty, New is Old and S is still empty

{S.top ?V}

returns the value V available on top of S without actually removing it

{S.toList ?L}

returns the list L of all values in S

{S.toListKill ?L}

returns the list L of all values in S and makes S unusable until a subsequent {S.reset}.

{S.isEmpty ?B}

returns true iff S is empty

{S.reset}

discards S's content and resets it to an empty stack

{S.clone ?S2}

returns a new functional queue instance S2 which is a clone of S