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/*
* We get this one wrong too.
*
* It should result in a sequence
*
* B ( )
* A ( )
* B ( )
* A ( )
*
* because each iteration of the scanning of "SCAN()"
* should re-evaluate the recursive B->A->B expansion.
* But we never re-evaluate something that we noticed
* was recursive. So we will cause it to evaluate to
*
* B ( )
* A ( )
* A ( )
* A ( )
*
* Which is really quite wrong.
*
* Did I already mention that the C preprocessor language
* is a perverse thing?
*/
#define LP (
#define A() B LP )
#define B() A LP )
#define SCAN(x) x
A() // B ( )
SCAN( A() ) // A ( )
SCAN(SCAN( A() )) // B ( )
SCAN(SCAN(SCAN( A() ))) // A ( )
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