Re: bootstrap problem with union Lisp_Object

[Ken Raeburn]

On Dec 6, 2005, at 11:30, Andreas Schwab wrote:
> > Try it with asserts (and without GCC extensions, of course).
>
> IMHO it would be reasonable to require GCC when building with
> -DENABLE_CHECKING.

If people think this is a good idea, I could start changing those  
macros that use eassert (XSET, XCONS, XVECTOR, ...) to have GCC and  
non-GCC versions, with the GCC versions using statement expressions  
(inline functions wouldn't preserve the file and line number) and  
temporary variables, and error out if ENABLE_CHECKING is defined but  
GCC isn't used.  Should be straightforward, about a dozen places or  
so to change I think.

>   In any case I think that least the basic macros like
> NILP and EQ should be side effect safe.

It would be nice.  CAR and CDR already fail that test for other  
reasons, though.  With ENABLE_CHECKING, most of the basic Lisp object  
manipulation macros do, because they double-check that the type is  
correct before extracting data.

Ken