Re: [Patch] hard-widen-limits [was Re: Syntax tables for multiple modes [was: bug#22983: syntax-ppss returns wrong result.]]

[Stefan Monnier]

> +  DEFVAR_LISP ("hard-widen-limits", Vhard_widen_limits,
> +            doc: /* When non-nil `widen` will widen to these limits.
> +Must be a cons of the form (MIN . MAX) where MIN and MAX are integers or 
> markers.  */);
> +  Vhard_widen_limits = Qnil;

Sorry to nitpick, but I'm not completely happy with this API.  As an
implementation it might be OK, but I can imagine wanting to change the
implementation in the future but being stuck by the exposed internals.

So I suggest we instead expose only a new primitive
"call-with-hard-narrowing" which could look like:

    (defun call-with-hard-narrowing (from to func)
      (make-local-variable 'internal--hard-widen-limits)
      (let ((internal--hard-widen-limits (cons from to)))
        (funcall func)))

which could be supplemented with a corresponding macro

    (defmacro with-hard-narrowing (from to &rest body)
      `(call-with-hard-narrowing ,from ,to (lambda () ,body)))


-- Stefan