factgen.c

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/*******************************************************/
/* FactGenGetfield: Generates an expression for use in */
/*   the fact pattern network that retrieves a value   */
/*   from a single or multifield slot.                 */
/*******************************************************/
globle struct expr *FactGenGetfield(theNode)
  struct lhsParseNode *theNode;
  {
   /*===================================================*/
   /* Generate call to retrieve single field slot value */
   /* or the fact relation name.                        */
   /*===================================================*/
   
   if ((theNode->slotNumber > 0) && (theNode->withinMultifieldSlot == CLIPS_FALSE))
     { return(GenConstant(FACT_PN_VAR2,FactGetVarPN2(theNode))); }
   
   /*=====================================================*/
   /* Generate call to retrieve a value from a multifield */
   /* slot that contains at most one multifield variable  */
   /* or contains no multifield variables before the      */
   /* value to be retrieved.                              */
   /*=====================================================*/
     
   if (((theNode->type == SF_WILDCARD) || (theNode->type == SF_VARIABLE)) &&
       ((theNode->multiFieldsBefore == 0) ||
        ((theNode->multiFieldsBefore == 1) && (theNode->multiFieldsAfter == 0)))) 
     { return(GenConstant(FACT_PN_VAR3,FactGetVarPN3(theNode))); }
   
   if (((theNode->type == MF_WILDCARD) || (theNode->type == MF_VARIABLE)) &&
       (theNode->multiFieldsBefore == 0) && (theNode->multiFieldsAfter == 0))
     { return(GenConstant(FACT_PN_VAR3,FactGetVarPN3(theNode))); }
     
   /*=========================================*/
   /* Generate call to retrieve a value using */
   /* the most general retrieval function.    */
   /*=========================================*/
   
   return(GenConstant(FACT_PN_VAR1,FactGetVarPN1(theNode)));
  }

/**************************************************/
/* FactGenGetvar: Generates an expression for use */
/*   in the join network that retrieves a value   */
/*   from a single or multifield slot of a fact.  */
/**************************************************/
globle struct expr *FactGenGetvar(theNode)
  struct lhsParseNode *theNode;
  {
   /*====================================================*/
   /* Generate call to retrieve single field slot value. */
   /*====================================================*/
   
   if ((theNode->slotNumber > 0) && (theNode->withinMultifieldSlot == CLIPS_FALSE))
     { return(GenConstant(FACT_JN_VAR2,FactGetVarJN2(theNode))); }
     
   /*=====================================================*/
   /* Generate call to retrieve a value from a multifield */
   /* slot that contains at most one multifield variable  */
   /* or contains no multifield variables before the      */
   /* value to be retrieved.                              */
   /*=====================================================*/
     
   if (((theNode->type == SF_WILDCARD) || (theNode->type == SF_VARIABLE)) &&
       ((theNode->multiFieldsBefore == 0) ||
        ((theNode->multiFieldsBefore == 1) && (theNode->multiFieldsAfter == 0)))) 
     { return(GenConstant(FACT_JN_VAR3,FactGetVarJN3(theNode))); }
   
   if (((theNode->type == MF_WILDCARD) || (theNode->type == MF_VARIABLE)) &&
       (theNode->multiFieldsBefore == 0) && 
       (theNode->multiFieldsAfter == 0))
     { return(GenConstant(FACT_JN_VAR3,FactGetVarJN3(theNode))); }
   
   /*=========================================*/
   /* Generate call to retrieve a value using */
   /* the most general retrieval function.    */
   /*=========================================*/
   
   return(GenConstant(FACT_JN_VAR1,FactGetVarJN1(theNode)));
  }
  
/**************************************************************/
/* FactGenCheckLength: Generates an expression for use in the */
/*   fact pattern network that determines if the value of a   */
/*   multifield slot contains enough fields to satisfy the    */
/*   number of pattern matching constaints. For example, the  */
/*   slot constraints (foo ?x a $? ?y) couldn't be matched    */
/*   unless the foo slot contained at least 3 fields.         */
/**************************************************************/
globle struct expr *FactGenCheckLength(theNode)
  struct lhsParseNode *theNode;
  {
   struct factCheckLengthPNCall hack;     
     
   /*===================================================*/
   /* If the slot contains no single field constraints, */
   /* then a length test is not necessary.              */
   /*===================================================*/
   
   if ((theNode->singleFieldsAfter == 0) && 
       (theNode->type != SF_VARIABLE) && 
       (theNode->type != SF_WILDCARD))
     { return(NULL); }
   
   /*=======================================*/
   /* Initialize the length test arguments. */
   /*=======================================*/
   
   ClearBitString(&hack,sizeof(struct factCheckLengthPNCall));
   hack.whichSlot = theNode->slotNumber - 1;
   
   /*============================================*/
   /* If the slot has no multifield constraints, */
   /* then the length must match exactly.        */
   /*============================================*/
   
   if ((theNode->type != MF_VARIABLE) &&
       (theNode->type != MF_WILDCARD) &&
       (theNode->multiFieldsAfter == 0))
     { hack.exactly = 1; }
   else
     { hack.exactly = 0; }
     
   /*============================================*/
   /* The minimum length is the number of single */
   /* field constraints contained in the slot.   */
   /*============================================*/
   
   if ((theNode->type == SF_VARIABLE) || (theNode->type == SF_WILDCARD))
     { hack.minLength = 1 + theNode->singleFieldsAfter; }
   else
     { hack.minLength = theNode->singleFieldsAfter; }
   
   /*========================================================*/
   /* Generate call to test the length of a multifield slot. */
   /*========================================================*/

   return(GenConstant(FACT_SLOT_LENGTH,AddBitMap(&hack,sizeof(struct factCheckLengthPNCall))));
  }

/**************************************************************/
/* FactGenCheckZeroLength: Generates an expression for use in */
/*   the fact pattern network that determines if the value of */
/*   a multifield slot is a zero length multifield value.     */
/**************************************************************/
globle struct expr *FactGenCheckZeroLength(theSlot)
  int theSlot;
  {
   struct factCheckLengthPNCall hack;     

   ClearBitString(&hack,sizeof(struct factCheckLengthPNCall));
   
   hack.whichSlot = theSlot-1;
   hack.exactly = 1;
   hack.minLength = 0;
   
   return(GenConstant(FACT_SLOT_LENGTH,AddBitMap(&hack,sizeof(struct factCheckLengthPNCall))));
  } 
  
/*********************************************************************/
/* FactReplaceGetvar: Replaces a variable reference in an expression */
/*   with a function call to retrieve the variable using the join    */
/*   network variable access functions for facts.                    */
/*********************************************************************/
globle VOID FactReplaceGetvar(theItem,theNode)
  struct expr *theItem;
  struct lhsParseNode *theNode;
  {
   /*====================================================*/
   /* Generate call to retrieve single field slot value. */
   /*====================================================*/

   if ((theNode->slotNumber > 0) && (theNode->withinMultifieldSlot == CLIPS_FALSE))
     {
      theItem->type = FACT_JN_VAR2;
      theItem->value = FactGetVarJN2(theNode);
      return;
     }
   
   /*=====================================================*/
   /* Generate call to retrieve a value from a multifield */
   /* slot that contains at most one multifield variable  */
   /* or contains no multifield variables before the      */
   /* value to be retrieved.                              */
   /*=====================================================*/

   if (((theNode->type == SF_WILDCARD) || (theNode->type == SF_VARIABLE)) &&
       ((theNode->multiFieldsBefore == 0) ||
        ((theNode->multiFieldsBefore == 1) && (theNode->multiFieldsAfter == 0)))) 
     {
      theItem->type = FACT_JN_VAR3;
      theItem->value = FactGetVarJN3(theNode);
      return;
     }
   
   if (((theNode->type == MF_WILDCARD) || (theNode->type == MF_VARIABLE)) &&
       (theNode->multiFieldsBefore == 0) && 
       (theNode->multiFieldsAfter == 0))
     { 
      theItem->type = FACT_JN_VAR3;
      theItem->value = FactGetVarJN3(theNode);
      return;
     }
   
   /*=========================================*/
   /* Generate call to retrieve a value using */
   /* the most general retrieval function.    */
   /*=========================================*/

   theItem->type = FACT_JN_VAR1;
   theItem->value = FactGetVarJN1(theNode);
  }
  
/***********************************************************************/
/* FactReplaceGetfield: Replaces a variable reference in an expression */
/*   with a function call to retrieve the variable using the pattern   */
/*   network variable access functions for facts.                      */
/***********************************************************************/
globle VOID FactReplaceGetfield(theItem,theNode)
  struct expr *theItem;
  struct lhsParseNode *theNode;
  {
   /*====================================================*/
   /* Generate call to retrieve single field slot value. */
   /*====================================================*/

   if (theNode->withinMultifieldSlot == CLIPS_FALSE)
     {
      theItem->type = FACT_PN_VAR2;
      theItem->value = FactGetVarPN2(theNode);
      return;
     }
   
   /*=====================================================*/
   /* Generate call to retrieve a value from a multifield */
   /* slot that contains at most one multifield variable  */
   /* or contains no multifield variables before the      */
   /* value to be retrieved.                              */
   /*=====================================================*/

   if (((theNode->type == SF_WILDCARD) || (theNode->type == SF_VARIABLE)) &&
       ((theNode->multiFieldsBefore == 0) ||
        ((theNode->multiFieldsBefore == 1) && (theNode->multiFieldsAfter == 0)))) 
     {
      theItem->type = FACT_PN_VAR3;
      theItem->value = FactGetVarPN3(theNode);
      return;
     }
   
   if (((theNode->type == MF_WILDCARD) || (theNode->type == MF_VARIABLE)) &&
       (theNode->multiFieldsBefore == 0) && 
       (theNode->multiFieldsAfter == 0))
     { 
      theItem->type = FACT_PN_VAR3;
      theItem->value = FactGetVarPN3(theNode);
      return;
     }
   
   /*=========================================*/
   /* Generate call to retrieve a value using */
   /* the most general retrieval function.    */
   /*=========================================*/

   theItem->type = FACT_PN_VAR1;
   theItem->value = FactGetVarPN1(theNode);
  }

/*************************************************************/
/* FactGetVarJN1: Creates the arguments for the most general */
/*   routine for retrieving a variable's value from the slot */
/*   of a fact. The retrieval relies on information stored   */
/*   in a partial match, so this retrieval mechanism is used */
/*   by expressions in the join network or from the RHS of a */
/*   rule.                                                   */    
/*************************************************************/
static VOID *FactGetVarJN1(theNode)
  struct lhsParseNode *theNode;
  {
   struct factGetVarJN1Call hack;

   /*===================================================*/
   /* Clear the bitmap for storing the argument values. */
   /*===================================================*/