Path: utzoo!attcan!uunet!mcvax!ukc!dcl-cs!aber-cs!pcg
From: pcg@aber-cs.UUCP (Piercarlo Grandi)
Newsgroups: comp.lang.smalltalk
Subject: Re: Quest. on Smalltalk
Summary: Have a look at MUST
Message-ID: <461@aber-cs.UUCP>
Date: 22 Dec 88 19:09:04 GMT
Reply-To: pcg@cs.aber.ac.uk (Piercarlo Grandi)
Distribution: eunet,world
Organization: CS Dept., University College of Wales, Aberystwyth, UK
	(Disclaimer: my statements are purely personal)
Lines: 30

In article <6037@louie.udel.EDU> new@udel.EDU (Darren New) writes:

    In article <80500047@p.cs.uiuc.edu> johnson@p.cs.uiuc.edu writes:

    >In general, however, perform: is safer and will probably do what
    >you want.  Blocks can also often be used as the solution to problems
    >of this type, as Scheme programmers well know.
    
    Except that blocks are not reentrant. Also, if a block executes a return
    (^), then it may not be called again.  Beware of this - it is very hard
    to debug.

I suggest that if you are interested in this you get a set of pretty good
papers from the Mushroom project at the U. of Manchester. They are building a
timesharing system based on a cleaned up Smalltalk-80, called MUST (an
imperative language! :->).

This MUST is a nice evolution of the original. As to blocks, let me quote
from their paper:

    BLOCKS: In MUST, the semantics of block activations has been "cleaned
    up". Blocks can have temporaries, are re-entrant, and are full
    continuations.

I think that any of {ifor,miw,trevor}@ux.cs.man.cs.ac.uk will be happy to
provide you with a copy of their relevant documents.
-- 
Piercarlo "Peter" Grandi			INET: pcg@cs.aber.ac.uk
Sw.Eng. Group, Dept. of Computer Science	UUCP: ...!mcvax!ukc!aber-cs!pcg
UCW, Penglais, Aberystwyth, WALES SY23 3BZ (UK)