#!/usr/bin/rexx
/*----------------------------------------------------------------------------*/
/* */
/* Copyright (c) 1995, 2004 IBM Corporation. All rights reserved. */
/* Copyright (c) 2005-2006 Rexx Language Association. All rights reserved. */
/* */
/* This program and the accompanying materials are made available under */
/* the terms of the Common Public License v1.0 which accompanies this */
/* distribution. A copy is also available at the following address: */
/* http://www.oorexx.org/license.html */
/* */
/* Redistribution and use in source and binary forms, with or */
/* without modification, are permitted provided that the following */
/* conditions are met: */
/* */
/* Redistributions of source code must retain the above copyright */
/* notice, this list of conditions and the following disclaimer. */
/* Redistributions in binary form must reproduce the above copyright */
/* notice, this list of conditions and the following disclaimer in */
/* the documentation and/or other materials provided with the distribution. */
/* */
/* Neither the name of Rexx Language Association nor the names */
/* of its contributors may be used to endorse or promote products */
/* derived from this software without specific prior written permission. */
/* */
/* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS */
/* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT */
/* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS */
/* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT */
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/* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED */
/* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, */
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/* */
/*----------------------------------------------------------------------------*/
/******************************************************************************/
/* stack.rex Open Object Rexx Samples */
/* */
/* A stack class */
/* */
/* -------------------------------------------------------------------------- */
/* */
/* Description: */
/* This program demonstrates how to implement a stack class using ::class */
/* and ::method directives. Also included is a short example of the use of */
/* a stack. */
/******************************************************************************/
mystack = .stack~new /* Create a new instance of stack */
mystack~push('John Smith')
mystack~push('Bill Brown')
say 'Size of stack:' mystack~items /* Displays size of stack */
say 'Pop stack: ' mystack~pop /* Displays item popped off stack */
say 'Pop stack: ' mystack~pop /* Displays next item popped off */
say 'Pop stack: ' mystack~pop /* Stack now empty - displays */
/* "The NIL Object" */
/* Define the stack class (a subclass of Object Class) */
::class stack
/* Define the init method on the stack class */
::method init
expose contents /* Object var with stack contents */
self~init:super /* Run init method of superclass */
contents = .list~new /* Use a list to keep stack items */
/* Define the push method on the stack class */
::method push
expose contents
use arg item
contents~insert(item, .nil)
/* Define the pop method on the stack class */
::method pop
expose contents
if contents~items > 0 then
return contents~remove(contents~first)
else
return .nil
/* Define the items method on the stack class to return number of items */
::method items
expose contents
return contents~items
