#define GET_NAME_CAUSAL(name, surname) name
#define GET_NAME_POLITE(name, surname) name surname
#define GREETINGS(mode, name, surname) Good day GET_NAME_##mode(name, surname).

// Good day James Bond.
GREETINGS(POLITE, James, Bond)
// Good day James.
GREETINGS(CAUSAL, James, Bond)