If you #define a recursive Definition you can go into a compiler overrun crash.

Example:
compile this prg and run

#define A A+

? [A] && result is a correct A+

compile this -> crash

#define A +A

? [A] && result is a ++++++++++++++++++.....

cause: preprocessor parser pointer is incremented by 1 ( cPointer++ )

Correct alghoritm is that used into STRTRAN()

? strtran('A','A','+A')

Fabio