Path: utzoo!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!hplabs!hplabsz!hasan
From: hasan@hplabsz.HP.COM (Waqar Hasan)
Newsgroups: comp.lang.scheme
Subject: Re: semantics of procedure calls
Message-ID: <6647@hplabsz.HP.COM>
Date: 4 Mar 91 19:02:16 GMT
References: <1991Feb28.230440.1762@Neon.Stanford.EDU> <1991Feb28.232008.26348@agate.berkeley.edu>
Organization: HPLabs, Palo Alto CA
Lines: 21

Thanks for the folks who replied to my question:

 Is the evaluation of arguments to a procedure
    (a) allowed to be concurrent
    (b) required to correspond to some serial order

(b) is the correct official answer. 

Can someone tell me why such a requirement makes sense? Wasnt Scheme
supposed to support concurrent evaluation? 
Is there any work/papers which show why (b) is preferable over (a)?

Interestingly, I got two replies which clarified that the language 
requires (b) and one reply which suggested that (a) made more sense.

I also got hold of a draft of the Scheme standard (P1178/D4) which 
clarifies the semantics to be (b).

-Waqar

hasan@hplabs.hp.com