Why won't this compile and how can it be implemented so that it does?

Question

Here is some C++ code I\'m playing around with:

#include 
#include 

#define IN ,
#define FOREACH(x,y) for(unsigned int i=0;i&l         


        

Answer 1

Expansion for IN doesn't happen early enough in your example, but you can pass the expanded version to another macro:

#define FOREACH(x) DO_FOREACH(x)
#define DO_FOREACH(x,y) for( ... ) ...