optional arguments

[Rick.Busdiecker@h.cs.cmu.edu]

Date: 30 Jan 87 11:30 PST
From: Gregor.pa@Xerox.COM
Subject: Re: questions from JEIDA Object Oriented Programming WG
 87 10:39:55
To: shochi.ishida@NTT-20.ARPA


Oops I should have answered this message sooner.

    At present, we have observed the followings.

    	  	    <case-1>                           <case-2>
      baz-a...   invalid(symbolics, Vaxlisp,kcl)    1(symbolics),10(kcl)
      bar-a...   10(symbolics,Vaxlisp,kcl)	        1(symbolics),10(kcl)
      foo-a...   10(symbolics,Vaxlisp),1(kcl)	1(symbolics,kcl)


The result you observed with ndefstruct and defstruct are all correct.
ndefstruct with :class class does not define new accessor methods for
inherited slots.  You should stop using ndefstruct and start using
defclass in your code and I think you will find this less confusing.


     PCL  does  not  handle  multi-methods  when  those  arities  are
different.  

Right, every method on a generic function must have the same number of
required, and optional arguments.  In addition, the must all agree about
whether &rest is accepted, and they must all accept the same keywords.