Re: variable type

[Eli Zaretskii]

[Redirected to emacs-devel, where these issues should be discussed.]

On Thu, 7 Mar 2002, Werner LEMBERG wrote:

> How shall I define a variable which has the following properties:
> 
>   If nil, don't use it.
>   If t, use value 0.
>   If a positive integer, use it.
> 
> My idea is to represent this in C as an integer where nil maps to -1.

I'd define it as a Lisp_Object, and then use NATNUMP, STRINGP, NILP, etc. 
to see what its type and extract the value.  Emacs sources do that quite 
a lot.