Re: Declaring a local dynamic variable?

[Andreas Röhler]

Am 13.10.2013 15:37, schrieb Stefan Monnier:
> > > The above code has the same effect as
> > > - create global variable x, initialize it to 5
> > > - execute bla bla
> > > - change value of x to 6
> > No. Introduces a let-bound x, which is unrelated to global x
>
> You're confused.

Really?

So that's what I get:

(defvar x 5)
x->5

(let ((x 6))
  x)

->6 (#o6, #x6, ?\C-f)

x->5

GNU Emacs 24.3.50.1 (i686-pc-linux-gnu, GTK+ Version 2.24.10) of 2013-08-28

[ ... ]

> The real story is more complicated because the old value stashed on the
> stack includes the information about whether `x' was already defined or
> not,


Sure it's more complicated. We are taking about the use of symbols at Emacs 
Lisp level, not about internals.
BTW I'm not blaming anybody because something went wrong. Just saying: let's 
correct it.

Best,

Andreas

and more importantly because variables can be buffer-local, so it
> needs also to remember which buffer's value was modified and only restore
> `x' for that buffer.
>
>
>          Stefan