Re: [boost] PREPROCESSOR library questions

From: Vesa Karvonen (vesa.karvonen_at_[hidden])
Date: 2001-12-18 05:03:39

From: "Gustavo Guerra" <gustavobt_at_[hidden]>
> The docs mention a BOOST_PREPROCESSOR_WHILE but say:
> CURRENTLY THIS FEATURE IS FOR INTERNAL USE ONLY!
> So why does it even appear on the docs?

Well, because I was too lazy to exclude it. I was still researching for the
best way to implement it. WHILE will be documented soon. The version of WHILE
in the current Boost release is not the final version and should not be used.

> Why do the all the arithmetic operations (ADD,SUB,MUL,DIV) use "saturation
> arithmetic"?

Why not? Well, simply because it seems to make the library as a whole easier
to implement.

> Why don't just #define BOOST_PREPROCESSOR_ADD(X,Y) X+Y
> I'm sure there's a reason, but it would be nice if that appeared in the docs

The short answer is that X+Y is not a single token.

> Why the first include guards around the #include statement? They aren't
> needed

They reduce preprocessing time on some compilers, because the compiler does
not need to open the #included file.