Re: [Boost-users] [Parameter] Adding arguments to pack through macro?

"Johan Nilsson" writes:

Hi,

I guess that the subject line isn't even technically correct. What I'd like to do is to implement something like the following:

#define FOO(x) MyNamedParamFn(x, d = 3, e = 4)

Where e.g.

"FOO((a = 0, b = 1));"

would expand to the equivalent of:

MyNamedParamFn(a = 0, b= 1, d = 3, e = 4);

Is this possible?

Not with a C++03 preprocessor, because there's no way to "peel apart" a comma-separated list like (a = 0, b = 1) without knowing how many elements are in it. With a C99/C++0x preprocessor, you could do it. -- Dave Abrahams Boost Consulting www.boost-consulting.com