-- Copyright 1993-1998, by the Cecil Project
-- Department of Computer Science and Engineering, University of Washington
-- See the LICENSE file for license information.

--DOC Stacks are implemented as special interfaces to mutable lists.

template object stack[T];
private extend stack[`T] isa m_list[T];

  method collection_name(@:stack[`T]):string { "stack" }

  method push(s@:stack[`T], x:T):void { add_first(s, x); }
  method pop(s@:stack[`T]):T { remove_first(s) }
  method top(s@:stack[`T]):T { first(s) }

  method copy(s@:stack[`T]):stack[T] {
      let new:stack[T] := new_stack[T]();
      s.do(&(x:T){
	  new.add_last(x);
      });
      new }

  method new_stack[T]():stack[T] { concrete object isa stack[T] }