Using commas inside a macro without parenthesis: How can I mix and match with a template?

Question

Consider a simple macro:

#define ECHO(x) x

ECHO(foo(1, 2))

This produces the exact output we expect:

foo(1, 2)
         


        

Answer 1

A variadic macro may help:

#define ECHO(x...) x

ECHO(foo(1, 2))
ECHO(template)