Re: e and pi

[Stefan Monnier <monnier@iro.umontreal.ca>]

>> - in Emacs-23.3, define `e', `float-e', `pi', and `float-pi' and declare
>> `e' and `pi' obsolete, but without a make-obsolete-variable
>> (i.e. only in NEWS and in docstrings).
>> - in Emacs-24 keep float-e and float-pi but get rid of `e' and `pi'.
>> Can anyone think of a better solution?

> Lexically scoped constants.  I mean 
> (defconstant e ...)
> could declare that e is lexically scoped (but has a global binding).

Indeed, `pi' is a defconst and currently `e' is a defvar but wants to be
a defconst as well.  And indeed if `defconst' really defines a constant,
then it can be considered as a lexically scoped variable.

But such a convention would introduce a lot more breakage, since many
packages still use defconst for variables which they later on modify via
`let' or `setq', expecting dynamic scoping semantics.  Admittedly, such
packages should be getting more rare since I've added warnings in the
byte-compiler in Emacs-23 (or maybe even Emacs-22?) about setq and let
applied to defconst'd vars.

Still, I think this is more dangerous than renaming e and pi (which are
admittedly very rarely used).

OTOH maybe you meant to introduce a new `defconstant' that's like
`defconst' except that it declares the var as lexically scoped.
Hmm... I guess that could work.


        Stefan