🚀 go-pugleaf

In article <36.UUL1.3#8618@softrue.UUCP>, kearns@softrue.UUCP (Steven Kearns)
writes:
>> I have been struggling with an algebraic spec for a couple of days and
>> ...
>> More specifically, I am trying to specify a tree that has the notion of
>> a "current node", and operations to change the current node.  The ....
>> Jeff Offutt
>> Department of ISSE, George Mason University, Fairfax VA
>> email: ofut@gmuvax2.gmu.edu
>> phone: (703) 993-1654 (messages: 993-1640)
[...]
> 
> It has been shown that Majester's stack (sp?), which is a stack with 
> a pointer to an arbitrary element (if memory serves), requires an infinite
> set of algebraic axioms to specify.  

Only if you disallow auxiliary functions (functions not intended to be
implemented).

> The practical point is that algebraic specs are very poor at
> describing objects with state.  If you want to describe such an
> object, use a model based spec language (such as Z).

Could you give us a short example, say of the extended stack you mention
above?

> -steve
> 
> ********************************************************
> * Steven Kearns            ....uunet!softrue!kearns    *
> * Software Truth           softrue!kearns@uunet.uu.net *
> ********************************************************

Antediluvian newsbreak:           |  J. E. Fritz    (fritz@ruby.vcu.edu)
  Scientists discover 4th prime;  |  VCU and I don't talk _to_ each other,
  proof at eleven.                |  let alone for each other.