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From: kens@hpldola.HP.COM (Ken Shrum)
Newsgroups: comp.lang.smalltalk
Subject: Re: declarations vs smalltalk
Message-ID: <11670001@hpldola.HP.COM>
Date: Wed, 1-Jul-87 15:06:43 EDT
Article-I.D.: hpldola.11670001
Posted: Wed Jul  1 15:06:43 1987
Date-Received: Sat, 4-Jul-87 12:59:58 EDT
References: <245100009@orstcs>
Organization: HP Logic Design Oper. -ColoSpgs
Lines: 29

>In short, there seems to be an implicit conflict between strong typing, or
>typing of any sort, and polymorphism.  Strengthing one limits the other.
>Smalltalk has come down strongly on
>the side of polymorphism, and even I (Smalltalk heretic than I am) have a
>hard time imagining anything similar to Smalltalk that changes this.
>
>I am looking forward to hearing how I am all wrong, and how option number 5
>makes all problems go away.

>--tim budd (budd@oregon-state)

Smalltalk combines protocol definitions and method implementations into
a class.  Let us consider having a class Protocol whose instances
represent protocols.  Presumably the instances support operations to
join/intersect a set of protocols, etc.  Each class may have an
instance of Protocol associated with it, describing the protocol
presented by instances at runtime.

    5.  Type declarations state that 'the protocol of this object is a
        superset of this protocol'.

This information could be used only for type checking or it could also
be used at runtime.

This solution only solves the syntax problem, but supports polymorphism
as it is presently supported by Smalltalk.

	Ken Shrum
	hplabs!hpldola!kens