Re: Appending lists

[Emanuel Berg]

Stefan Monnier via Users list for the GNU Emacs text editor wrote:

>>>> Doing (foo x y) will *never* change "the variable x" -- unless
>>>> foo is a macro/special form.
>>> 
>>> Just to show that you should never say never:
>>> 
>>>     (let* ((x 5)
>>>            (y 6))
>>>       (cl-flet ((foo (a b) (setq x (+ a b) y (* a b)) (- a b)))
>>>         (list (foo x y) x y)))
>>
>> Hey, that's cheating :-)
>
> Impredicativity is borderline, indeed.

Impredicativity, what's that, recursion?

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