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From: jcg@iris.brown.edu (James Grandy)
Newsgroups: comp.lang.smalltalk
Subject: Re: Smalltalk Implementation Summary
Message-ID: <22792@brunix.UUCP>
Date: 13 Dec 89 17:08:43 GMT
References: <1989Dec6.235311.12726@comp.vuw.ac.nz>
Sender: news@brunix.UUCP
Organization: IRIS, Brown University
Lines: 28


In article <1989Dec6.235311.12726@comp.vuw.ac.nz> kjx@comp.vuw.ac.nz (R 
James Noble) (you) write(s):
> b) Blocks should be fully reentrant, and allow block temporaries.
> Syntax: [ :a1 :a2 | t1 t2 | ... ]
> 

Isn't this a bit hard to parse? How do you know, given that a block 
without temporaries looks like this:   [ :a1 :a2 | ... ] , 
whether t1 is the receiver of the first message in the block 
or a temporary? Of course, if you drop the bar separator when 
there are no arguments, not only is the block easier to parse, 
but it now looks more like a method header:
  
                          [ :a1 :a2   a1 foo: a2]

Then, with arguments, the block is as before:

                          [ :a1 :a2 | t1 t2 | t1 <- a1 foo a2 ]

Maybe not feasible if you want to be language compatible with other 
Smalltalks, but...


James Grandy
(401) 862-1610                jcg@iris.brown.edu
IRIS Brown University
Box 1946, Providence, RI 02912