Macro Pasting Hell

FailsToExpand.c

#define CALLONE(FUNCTION, ARGS...) FUNCTION(1 , ##ARGS)
CALLONE(add, CALLONE(addOne));

/* expands to */
add(1, CALLONE(addOne));

FailsToSwallowComma.c

#define _CALLONE(FUNCTION, ARGS...) FUNCTION(1 , ##ARGS)
#define CALLONE(FUNCTION, ARGS...) _CALLONE(FUNCTION, ARGS)
CALLONE(add, CALLONE(addOne));

/* expands to */
add(1, addOne(1, ));

Paste.c

#define PASTE(ARG1, ARG2) ARG1 ## ARG2

PASTE(Hello, World)();

/* expands to */
HelloWorld();

PasteBroken.c

#define PASTE(ARG1, ARG2) ARG1 ## ARG2

#define HELLO Hello
PASTE(HELLO, World)();

/* expands to */
HELLOWorld();

PasteFixed.c

#define _PASTE(ARG1, ARG2) ARG1 ## ARG2
#define PASTE(ARG1, ARG2) PASTE(ARG1, ARG2)

#define HELLO Hello
PASTE(HELLO, World)();

/* expands to */
HelloWorld();

Solution.c

#define ISEMPTY(ARGS...) /* Too complicated to put here, see http://gustedt.wordpress.com/2010/06/08/detect-empty-macro-arguments/ */

#define _PASTE(ARG1, ARG2) ARG1 ## ARG2
#define PASTE(ARG1, ARG2) PASTE(ARG1, ARG2)

#define CALLONE0(FUNCTION, ARGS...) FUNCTION(1, ARGS)
#define CALLONE1(FUNCTION, ARGS...) FUNCTION(1)
#define CALLONE(FUNCTION, ARGS...) PASTE(CALLONE,ISEMPTY(ARGS))(FUNCTION, ARGS)

CALLONE(add, CALLONE(addOne));

/* expands to */
add(1, addOne(1));

VariadicMacro.c

#define CALLONE(FUNCTION, ARGS...) FUNCTION(1 , ##ARGS)
CALLONE(myFunc);

/* expands to */
myFunc(1);