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yap-6.3/H/attvar.h
Vitor Santos Costa 53b4828000 new Atts Code.
2010-03-08 09:24:11 +00:00

69 lines
1.7 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).
*/
/*
attvar_entry is just a Prolog structure such that the first argument is
a pointer to the next args
*/
typedef struct attvar_struct {
Functor AttFunc; /* functor for attvar */
Term Done; /* if unbound suspension active, if bound terminated */
Term Value; /* value the variable will take */
Term Atts; /* actual data */
} attvar_record;
#define ATT_RECORD_ARITY 3
/*********** tags for suspension variables */
static inline Term
AbsAttVar(attvar_record *attvar_ptr) {
return attvar_ptr->Done;
}
static inline attvar_record *
RepAttVar(Term *var_ptr) {
return (attvar_record *)(var_ptr-1);
}
#endif