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From: pcg@aber-cs.UUCP (Piercarlo Grandi)
Newsgroups: comp.object
Subject: Re: Continuations
Summary: closures, the ultimate imperative and declarative...
Message-ID: <1502@aber-cs.UUCP>
Date: 4 Dec 89 15:40:45 GMT
Reply-To: pcg@cs.aber.ac.uk (Piercarlo Grandi)
Organization: Dept of CS, UCW Aberystwyth
	(Disclaimer: my statements are purely personal)
Lines: 20

It has been my long held belief that really objects and closures are much
the same thing, to a certain extent. In many ways you can simulate closures
with objects (especially if you have suspend/resume) and objects with
closures.

My reckoning has always been that the most powerful possible entity is a
triple (dictionary, code, saved state), where each member of the triple may
be possibly null. If you also have the three steps for procedure invocation
directly available, like in SL5, then you can do wonderful things, and even
more incredible ones if you can have code executed at compile time (e.g.
like in Lisp, or in the "supercompiler" concept). The BETA language has
"patterns" that are really something like this.

As to more mundane things, under certain respects most current popular OO
languages are a step backwards from Simula 67, e.g. detach/suspend/resume,
inner, and block prefixing, etc...
-- 
Piercarlo "Peter" Grandi           | ARPA: pcg%cs.aber.ac.uk@nsfnet-relay.ac.uk
Dept of CS, UCW Aberystwyth        | UUCP: ...!mcvax!ukc!aber-cs!pcg
Penglais, Aberystwyth SY23 3BZ, UK | INET: pcg@cs.aber.ac.uk