Re: Disabling automatic reindentation of the current line after a newline

[Emanuel Berg <incal@dataswamp.org>]

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

> To some extent, I think `setq` should basically

Note the word "basically" ...

> never be used other than on lexical variables: for
> non-lexical variables, we should either use `setq-default`
> or `setq-local` but never this `setq` which does sometime
> one thing and sometimes the other.

Because, most often it works like this, `setq' sets the
default/global value if that is set, but the _local_ if that
or both are set, and if neither are, it sets the default -
unless the variable is defined with DEFVAR_PER_BUFFER in C or
`make-local-variable' in Elisp, that means it "Automatically
becomes buffer-local when set" so then setq will be like
`setq-local' and not `setq-default' all tho none are
set. Phew!

Yes, most often ... but not always?

; don't use `setq' here, @#$&%!
(setq-local lexical-binding nil)

; because `lexical-binding' is dynamic/special, i.e. the variable itself
(special-variable-p 'lexical-binding)

 ; this function relies on a dynamic and/or special variable `n'
(defun use-var ()
  n)

; formal parameters are dynamic under dynabound
(defun lexfun (n)
  (setq n 1)
  (special-variable-p 'n) ; but not special since they are not global
  (use-var) )

;; (lexfun 2) ; 1

(special-variable-p 'n) ; nil

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