[plt-scheme] Re: Scheme workshop survey

From: Alan Watson (alan at alan-watson.org)
Date: Sun Oct 19 15:57:23 EDT 2008

The question at http://dynamo.iro.umontreal.ca/sw/survey/ has been  

The problem with regarding the (original) question as "what value does  
it reduce to?" and the convention that we "consider values to be a  
subset of expressions that do not require
further evaluation"  is that there is no standard means to write such  
an expression that will be eqv? to the required expression. Even Eli's  
answer doesn't get us there, as his expression produces a value that  
will be equal? to the required value, but once again not necessarily  
eqv?. That's why I say the original question is unanswerable.

If the original question had been, "what is the value of (car '(a b  
c)), we could regard 'a as a correct reply under these assumptions,  
because the values of both expressions will be eqv?.

Now, this depends on interpreting "is" as meaning "eqv?" rather than  
"equal?". However, one would not say that two different calls to (list  
'a 'b 'c) produced the same value (in Standard Scheme), so I think  
eqv? is this correct predicate here.


Alan Watson

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