Nope, that was it. I had thought progv would treat the binding with no argument
like a free binding. Instead, it explicitly unbinds the variable.
Thanks!
Greg
On Dec 27, 2010, at 8:43 AM, Peter Seibel wrote:
> I'm assuming you're surprised by the results of the forms you give
> below. The issue isn't that progv makes "a differest special"--it
> makes a new binding. So in the first form you've created a new binding
> for x with no supplied value so boundp returning NIL seems about
> right. And in the second case, you create a binding, assign it a
> value, and then leave the scope of the binding. Or I'm missing
> something about your question.
>
> -Peter
>
> On Sun, Dec 26, 2010 at 4:04 PM, Greg Gilley <[email protected]> wrote:
>>
>> There are some tests in the common-lisp test suite with dynamic binding that
>> I don't understand. If someone could help shed some light on them I'd
>> appreciate it.
>>
>> progv makes it's arguments special. I don't understand how they can be a
>> different special than the one declared in the let. I'd love an explanation.
>>
>> (let ((x 0))
>> (declare (special x))
>> (progv '(x) ()
>> (boundp 'x))) ==> NIL
>>
>> (let ((x 0))
>> (declare (special x))
>> (progv '(x) () (setq x 1))
>> x) ==> 0
>>
>> Thanks,
>>
>> Greg
>>
>>
>> _______________________________________________
>> pro mailing list
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>>
>
>
>
> --
> Peter Seibel
> http://www.codequarterly.com/
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