Re: Invalid function error in cl.el

[John Russell <jorussel@cisco.com>]

Pascal Bourguignon <usenet@informatimago.com> writes:

> John Russell <jorussel@cisco.com> writes:
>
>> I am using emacs 21.4.1 on Gentoo with buffer-stack.el.  Briefly its a
>> fairly common extension that allows you to switch quickly between
>> active buffers.  I have used it for years with no problems.  Great,
>> you say, but why do I care?
>>
>> Recently whenever I try to call buffer-stack-up or buffer-stack-down (
>> the main entry points for buffer-stack ) I get the following error
>>
>> buffer-stack-move: Invalid function: (macro lambda (place &optional x)
>> "Increment PLACE by X (1 by default). 
>> PLACE may be a symbol, or any generalized variable allowed by `setf'.
>> The return value is the incremented value of PLACE." (if (symbolp
>> place) (list (quote setq) place (if x (list (quote +) place x) (list
>> (quote 1+) place))) (list (quote callf) (quote +) place (or x 1))))
>>
>> I have tried reinstalling emacs, removing other things from my config,
>> byte compiled, not byte compiled, on an empty stomach, nothing helps.
>> The thing that kills me is that this has worked for so long and now
>> it doesn't.  It has to be something I did, but I can't for the life of
>> me figure it out.  Any ideas?  Thanks a lot.
>
> The form:
>
> (macro lambda (place &optional x)
>  "Increment PLACE by X (1 by default). 
>  PLACE may be a symbol, or any generalized variable allowed by `setf'.
>  The return value is the incremented value of PLACE." (if (symbolp
>  place) (list (quote setq) place (if x (list (quote +) place x) (list
>  (quote 1+) place))) (list (quote callf) (quote +) place (or x 1))))
>
> is not a function.  It looks like the body of the incf macro.
> Perhaps buffer-stack.el tries to funcall (symbol-function 'incf) ?
> It should avoid incf, since it's defined as a macro in cl-macs.el
>

This clip is in buffer-stack.el

 (incf buffer-stack-index)

I replaced it with 
  (setq buffer-stack-index (1+ buffer-stack-index))


Everything works as expected now, which is good, but this literally
worked for 3 years.  I have no idea why it would break now.  Eh,
anyway, thanks for the prod in the right direction.  

John