bug#18059: 24.3.92; defvar and special variables

[Michael Heerdegen <michael_heerdegen@web.de>]

Noam Postavsky <npostavs@users.sourceforge.net> writes:

> Right, because the defvar is not inside any let-block, so it applies to
> the rest of the file.
>
> Compare
>
>     ;; -*- lexical-binding: t -*-
>
>     (progn
>       (defvar x))
>
>     (let ((x 1))
>       (setq testfun (lambda () x)))
>
>     (message "%S" (funcall testfun))
>
> vs
>
>     ;; -*- lexical-binding: t -*-
>
>     (let (_)
>       (defvar x))
>
>     (let ((x 1))
>       (setq testfun (lambda () x)))
>
>     (message "%S" (funcall testfun))

Thanks for the examples.  Maybe - and this is my personal opinion - such
examples in the manual would not be too bad.  I find the issue hard to
understand without such examples, though it might be a secondary
subject.


> I noticed doing (let () (defvar x)) seems to be the same as (progn
> (defvar x)), which may be a bug.

I guess because the interpreter doesn't create a new lexical environment
in this case?  But indeed it seems to contradict the doc.


Michael.