Re: Appending lists

[Yuri Khan <yuri.v.khan@gmail.com>]

On Wed, 16 Jun 2021 at 16:35, Jean Louis <bugs@gnu.support> wrote:

> What is it doing in background, or underground, does not really matter
> for user, what matters is that `x' in following example is changed:

See, that’s your problem: You think there *is* an underground.

Lisp starts with symbols and cons cells and that’s the ground level.
It then builds up from that to lists and trees and associative lists.
And when you have an associative list binding a symbol to a value,
that’s when you get variables, some three floors above the ground.

And then, when you invoke ‘nreverse’ on a list pointed to by a
variable, you, from high up above, can see it scurrying down there and
re-routing the ‘cdr’s of the cons cells comprising the list, but not
touching the one link from the variable to whatever cons cell had been
the first in the list.