Re: constant `e'

[Juanma Barranquero]

On 2/9/07, Drew Adams <address@hidden> wrote:

> Obviously, renaming `e' now would break existing code, but if others agreed,
> then we might plan to deprecate `e' over time, in favor of a longer name.

I think that would be a good idea, if anything because the risk of
shadowing `e' with a local (unrelated) binding is quite high, and that
could be a difficult bug to spot.

>  ;; Careful when editing this file ... typos here will be hard to spot.
>  ;; (defconst pi       3.14159265358979323846264338327
>  ;;  "The value of Pi (3.14159265358979323846264338327...)")
>
> Perhaps that comment dated from some time (?) pre-Emacs 20 when `pi' was
> defined using explicit decimal notation

That's the only reasonable explanation. These comments should be deleted.

> Undefining it and seeing what happens would be one approach... Obviously not
> something to attempt before the release, in any case. ;-)

No :)

I find very curious this change by Stefan:

;; It's too inconvenient to make `e' a constant because it's used as
;; a temporary variable all the time.
(defvar e (exp 1) "The value of e (2.7182818...).")

But

 (let ((pi 3.2)) pi) => 3.2

so there's no problem with constants and temporary variables. I think
that must be related to some local patches he mentioned a while ago
for allowing real constants...

Am I right, Stefan, or did I misunderstand this comment in the code?

                   /L/e/k/t/u