Re: new "empty" value/type in Lua?

[Philipp Janda <siffiejoe@...>]

Am 02.07.2013 01:20 schröbte Sean Conner:
>    Actually, I've seen plenty of C code improperly define the value for true.
> In C, a value of 0 is considered false, and *anything but 0* is considered
> true, so (in my not so humble opinion) the best definition of TRUE and FALSE
> would be:
>
> #define FALSE	0
> #define TRUE	!FALSE
>
> But I've seen code that does:
>
> #define TRUE	1
> #define FALSE	0
>
> which mostly works, but can fail in some obscure cases.

For a conforming ISO C90+ compiler both cases are equivalent:

3.3.3.3 Unary arithmetic operators
[...]
The result of the logical negation operator ! is 0 if the value of
its operand compares unequal to 0, 1 if the value of its operand
compares equal to 0.  The result has type int .


Philipp