Re: master d62766305a: Add `take` and `ntake` (bug#56521)

[Robert Pluim <rpluim@gmail.com>]

>>>>> On Sun, 17 Jul 2022 11:47:25 -0400 (EDT), Mattias Engdegård <mattiase@acm.org> said:
 
    Mattias> +@defun ntake n list
    Mattias> +This is a version of @code{take} that works by destructively modifying
    Mattias> +the list structure of the argument.  That makes it faster, but the
    Mattias> +original value of @var{list} is lost.
    Mattias> +@end defun
    Mattias> +
    Mattias>  @defun last list &optional n
    Mattias>  This function returns the last link of @var{list}.  The @code{car} of
    Mattias>  this link is the list's last element.  If @var{list} is
    Mattias> null,

Does this need the usual blurb to do

(setq list-var (ntake 3 list-var))

to ensure `list-var' is updated?

    Mattias> +DEFUN ("take", Ftake, Stake, 2, 2, 0,
    Mattias> +       doc: /* Return the first N elements of LIST.
    Mattias> +If N is zero or negative, return nil.
    Mattias> +If LIST is no more than N elements long, return it (or a copy).  */)
    Mattias> +  (Lisp_Object n, Lisp_Object list)

I think this would be clearer as

"If N is >= the length of LIST, return LIST (or a copy)."

since weʼre talking about the effect of various values of N.

    Mattias> +
    Mattias> +DEFUN ("ntake", Fntake, Sntake, 2, 2, 0,
    Mattias> +       doc: /* Modify LIST to keep only the first N elements.
    Mattias> +If N is zero or negative, return nil.
    Mattias> +If LIST is no more than N elements long, return it.  */)

And similarly here.

Robert
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