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yap-6.3/H/attvar.h
2005-02-18 21:34:02 +00:00

71 lines
1.9 KiB
C

/*************************************************************************
* *
* YAP Prolog *
* *
* Yap Prolog was developed at NCCUP - Universidade do Porto *
* *
* Copyright L.Damas, V.S.Costa and Universidade do Porto 1985-1997 *
* *
**************************************************************************
* *
* File: corout.c *
* Last rev: *
* mods: *
* comments: Co-routining from within YAP *
* *
*************************************************************************/
#ifdef SCCS
static char SccsId[]="%W% %G%";
#endif
#ifdef COROUTINING
/*
Attributed variales are controlled by the attvar_record. This includes
three pieces of information:
A pointer to the list of attributes;
The value for the variable, if the variable was bound
Whether we are done with this variable as an attributed variable
An array of NUM_OF_ATTS attributes.
Each attribute contains;
o a time stamp;
o the current value ([] if unbound).
*/
typedef struct attvar_struct {
Term Done; /* if unbound suspension active, if bound terminated */
CELL sus_id;
Term NS; /* other attributed variables */
Term Value; /* value the variable will take */
#ifdef __GNUC__
/* GNUCC understands empty arrays */
Term Atts[0];
#else
Term Atts[2]; /* size of an entry */
#endif
} attvar_record;
/*********** tags for suspension variables */
#define AbsAttVar(attvar_ptr) AbsAppl(((CELL *)(attvar_ptr)))
#define RepAttVar(val) ((attvar_record *)RepAppl(val))
static inline attvar_record *
DelayTop(void) {
return (attvar_record *)((CELL *)Yap_GlobalBase+IntegerOfTerm(Yap_ReadTimedVar(DelayedVars)));
}
static inline void
SetDelayTop(CELL *new_top) {
Yap_UpdateTimedVar(DelayedVars, MkIntegerTerm((CELL)(new_top-(CELL *)Yap_GlobalBase)));
}
#endif