more build problems, STEP-FUN in LOOP must be a function

Andreas Eder wrote:
> Raymond wrote:
> 
>> Andreas Eder wrote:
>>> Rainer wrote:
>>>
>>>> Maxima 5.12.0
>>>>
>>>>
>>>> I see code like this:
>>>>
>>>>
>>>> ratmac.lisp
>>>>
>>>> (defmacro pt-red (terms) `(cddr ,terms))
>>>>
>>>>
>>>>
>>>> rat3a.lisp
>>>>
>>>> (defun pctimes1 (c terms)
>>>>   (loop for (exp coef) on terms by #'pt-red
>>>>     unless (pzerop (setq coef (ptimes c coef)))
>>>>     nconc (list exp coef)))
>>>>
>>>>
>>>>
>>>> ANSI Common Lisp defines the STEP-FUN in LOOP
>>>> to be a function. We cannot use a macro here.
>>> Corrected in cvs.
>> I disagree with your fix.  Wouldn't the right solution be to make pt-red 
>> a inline function?  Then the issue is fixed everywhere.  I don't know 
>> what pt-red really means, but it seems clear that the original author(s) 
>> were trying to abstract out the representation, and I don't think we 
>> should remove that abstraction.
> 
> Yes, pt-red is a kind of abstraction for data access, but in the
> loop code it was used inappropriately. Look at the code mentioned
> above: it loops on a list in pairs, so the step is just by cddr.
> That's natural and obvious - no data access.
> 
> So I still think the fix was right.

That still breaks the abstraction.  PT-RED as a function would work 
everywhere, without having to edit all uses of it as a step function in 
a loop.

Ray