[plt-scheme] V4 request for thoughts on various question

Robby Findler robby at cs.uchicago.edu
Mon Aug 4 12:28:53 EDT 2008


On Mon, Aug 4, 2008 at 11:08 AM, Grant Rettke <grettke at acm.org> wrote:
> <robby at cs.uchicago.edu> wrote:
>> The constraint is on the values produced, not on the evaluation order per se. Specifically, this:
>>
>> (define q 0)
>> (let ([x (begin (set! q (+ q 1)) 1)]
>>      [y (begin (set! q (- q 1)) 1)])
>>  q)
>>
>> must evaluate to 0, not -1 or +1.
>
> When you say "values produced", do you mean values that are bound to
> the names in the name value pairs, or ordering in which the value
> expressions themselves are evaluated (x then y versus y then x)?

I just mean the result of the let expression.

Robby



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