RE: e and pi

[Drew Adams]

> > I once had a function with an argument called system-name.  Suddenly
> > Emacs started to complain that some files are locked by 
> > some other user. How many people now that system-name is a global
> > variable and used by the file-locking code?
> >
> > The lesson is that Emacs should not pre-define global variables with
> > names that are likely candidates for local variables.
> 
> What you describe as a big surprise is actually known to every C/C++
> programmer: some names are "reserved by the implementation" and should
> not be used by the application code.

And can you imagine the fun if C/C++ reserved the name `e'? ;-)

Please read what the OP wrote: "should not pre-define global variables with
names that are _likely candidates for local variables_".  That likelihood is
very high for `e', whether in C/C++ or Emacs Lisp.  It is presumably not so high
for the implementation-reserved names of C/C++.  (And since when did their
design become a guide for Emacs Lisp?)