#define _PDCLIB_symbol2value( x ) #x
#define _PDCLIB_symbol2string( x ) _PDCLIB_symbol2value( x )
#define _PDCLIB_symbol2identity( x ) x
#define _PDCLIB_symbol2value( x ) #x
#define _PDCLIB_symbol2string( x ) _PDCLIB_symbol2value( x )
#define _PDCLIB_symbol2identity( x ) x