[Openmcl-devel] Trunk and released version

[Ron Garret]

That should, of course, have read "... is NOT all that inexplicable."

On Aug 13, 2009, at 9:43 AM, Ron Garret wrote:

> I dunno, I don't think copying the declarations is all that
> inexplicable.  After all, an implementation is allowed to assign VAR
> instead of rebinding it as CCL does, in which case you'd have no
> choice but to have the declarations apply in the scope of the result
> form.
>
> rg
>
> On Aug 13, 2009, at 8:56 AM, Gary Byers wrote:
>
>> I'd call it a bug in the version of DOLIST that was in the trunk  
>> until
>> about an hour ago.  (It was establishing a new binding of VAR to NIL
>> around the result form, but inexplicably copying the declarations  
>> from
>> the main body into the body of the LET or LET* that established that
>> binding.)
>> So something like:
>>
>> (let* ((sum 0))
>> (dolist (i list sum)
>>   (declare (fixnum i))
>>   (incf sum i)))
>>
>> was expanding into something like:
>>
>> (uninteresting-loop
>> ...
>> (declare (fixnum i)) ; OK
>> ...
>> (when done (let* ((i nil))
>>              (declare (fixnum i)) ; unintentional, I assume.
>>               sum))
>>
>> which certainly deserves a runtime error at high safety, probably
>> deserves a compile-time warning, and is a result of a bug in DOLIST.
>>
>>
>>
>>
>> On Thu, 13 Aug 2009, Ron Garret wrote:
>>
>>> I'd call that a bug in the ANSI spec.  It violates the principle of
>>> least
>>> surprise for no benefit whatsoever.  If X is unconditionally bound
>>> to NIL
>>> then there is no point in even having it in scope when the result-
>>> form is
>>> evaluated.
>>> rg
>>> On Aug 13, 2009, at 6:28 AM, Tim Bradshaw wrote:
>>>
>>>     On 13 Aug 2009, at 12:31, Arthur W Cater wrote:
>>>
>>>     a form like
>>>  (dolist (X list-of-xs    expr-not-using-X)
>>>      (declare (type mytype X))
>>>      stuff-involving-X)
>>> provoking a complaint that NIL is not of type MYTYPE
>>> I'm pretty sure that's not a bug.  X is defined to be bound to NIL
>>> when the result-form is evaluated.  So unless NIL is an instance of
>>> MYTYPE your declaration is wrong.
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>>> Openmcl-devel at clozure.com
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>>>
>
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