[plt-scheme] Please help test version 359.100

From: Dave Herman (dherman at ccs.neu.edu)
Date: Tue Nov 14 11:12:51 EST 2006

>>    Since the value returned by "for-each" is left unspecified
> But it isn't left unspecified. It is specified to be the specified
> thing that the r5 report just calls "unspecified". (how confusing is
> that?!)

I had thought it was only in R6RS where they explicitly specified a 
thing called the "unspecified value," whereas in R5RS it's left ambiguous.

I did a quick grep of R5RS and found that the phrase "an unspecified 
value" occurs 7 times in R5RS (all in section 6), whereas there are no 
occurrences of "the unspecified value." The use of the indefinite 
article "an" suggests that for *each* occurrence of the phrase, the 
value in question may be any value.

However, in the denotational semantics, it appears that there is a 
single value called /unspecified/, suggesting that there is only one 
global value representing *the* unspecified value. However, the 
denotational semantics is known to be questionable, particularly in 
modeling these sorts of things (cf. the iffy evaluation-order hack).

In this case, I think I might trust the English over the Greek.


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