prcdrfun.c

NASA 开发使用的一个专家系统

   /*******************************************************/
   /*      "C" Language Integrated Production System      */
   /*                                                     */
   /*             CLIPS Version 6.05  04/09/97            */
   /*                                                     */
   /*             PROCEDURAL FUNCTIONS MODULE             */
   /*******************************************************/

/*************************************************************/
/* Purpose: Contains the code for several procedural         */
/*   functions including if, while, loop-for-count, bind,    */
/*   progn, return, break, and switch                        */
/*                                                           */
/* Principal Programmer(s):                                  */
/*      Gary D. Riley                                        */
/*      Brian L. Donnell                                     */
/*                                                           */
/* Contributing Programmer(s):                               */
/*                                                           */
/* Revision History:                                         */
/*                                                           */
/*************************************************************/

#define _PRCDRFUN_SOURCE_

#include <stdio.h>
#define _CLIPS_STDIO_

#include "setup.h"

#include "clipsmem.h"
#include "router.h"
#include "argacces.h"
#include "constrnt.h"
#include "cstrnchk.h"
#include "cstrnops.h"
#include "multifld.h"
#include "exprnpsr.h"
#include "scanner.h"
#include "utility.h"
#include "prcdrpsr.h"
#include "prcdrfun.h"

#if DEFGLOBAL_CONSTRUCT 
#include "globldef.h" 
#endif

typedef struct loopCounterStack
  {
   long loopCounter;
   struct loopCounterStack *nxt;
  } LOOP_COUNTER_STACK;
  
/****************************************/
/* GLOBAL INTERNAL VARIABLE DEFINITIONS */
/****************************************/

   globle int                 ReturnFlag = CLIPS_FALSE;
   globle int                 BreakFlag = CLIPS_FALSE;

/***************************************/
/* LOCAL INTERNAL VARIABLE DEFINITIONS */
/***************************************/

   static LOOP_COUNTER_STACK *LoopCounterStack = NULL;
   static struct dataObject  *BindList = NULL;

#if ! RUN_TIME
/**********************************************/
/* ProceduralFunctionDefinitions: Initializes */
/*   the procedural functions.                */
/**********************************************/
globle VOID ProceduralFunctionDefinitions()
  {
   DefineFunction2("if", 'u', PTIF IfFunction, "IfFunction", NULL);
   DefineFunction2("while", 'u', PTIF WhileFunction, "WhileFunction", NULL);
   DefineFunction2("loop-for-count",'u', PTIF LoopForCountFunction, "LoopForCountFunction", NULL);
   DefineFunction2("(get-loop-count)",'l', PTIF GetLoopCount, "GetLoopCount", NULL);
   DefineFunction2("bind", 'u', PTIF BindFunction, "BindFunction", NULL);
   DefineFunction2("progn", 'u', PTIF PrognFunction, "PrognFunction", NULL);
   DefineFunction2("return", 'u', PTIF ReturnFunction, "ReturnFunction",NULL);
   DefineFunction2("break", 'v', PTIF BreakFunction, "BreakFunction",NULL);
   DefineFunction2("switch", 'u', PTIF SwitchFunction, "SwitchFunction",NULL);

   ProceduralFunctionParsers();

   FuncSeqOvlFlags("progn",CLIPS_FALSE,CLIPS_FALSE);
   FuncSeqOvlFlags("if",CLIPS_FALSE,CLIPS_FALSE);
   FuncSeqOvlFlags("while",CLIPS_FALSE,CLIPS_FALSE);
   FuncSeqOvlFlags("loop-for-count",CLIPS_FALSE,CLIPS_FALSE);
   FuncSeqOvlFlags("return",CLIPS_FALSE,CLIPS_FALSE);
   FuncSeqOvlFlags("switch",CLIPS_FALSE,CLIPS_FALSE);
  }
#endif

/***************************************/
/* WhileFunction: CLIPS access routine */
/*   for the while function.           */
/***************************************/
globle VOID WhileFunction(returnValue)
  DATA_OBJECT_PTR returnValue;
  {
   DATA_OBJECT theResult;

   /*====================================================*/
   /* Evaluate the body of the while loop as long as the */
   /* while condition evaluates to a non-FALSE value.    */
   /*====================================================*/
   
   CurrentEvaluationDepth++;
   RtnUnknown(1,&theResult);
   while (((theResult.value != CLIPSFalseSymbol) ||
           (theResult.type != SYMBOL)) &&
           (HaltExecution != CLIPS_TRUE))
     {
      if ((BreakFlag == CLIPS_TRUE) || (ReturnFlag == CLIPS_TRUE))
        break;
      RtnUnknown(2,&theResult);
      CurrentEvaluationDepth--;
      if (ReturnFlag == CLIPS_TRUE)
        { PropagateReturnValue(&theResult); }
      PeriodicCleanup(CLIPS_FALSE,CLIPS_TRUE);
      CurrentEvaluationDepth++;
      if ((BreakFlag == CLIPS_TRUE) || (ReturnFlag == CLIPS_TRUE))
        break;
      RtnUnknown(1,&theResult);
     }
   CurrentEvaluationDepth--;

   /*=====================================================*/
   /* Reset the break flag. The return flag is not reset  */
   /* because the while loop is probably contained within */
   /* a deffunction or RHS of a rule which needs to be    */
   /* returned from as well.                              */
   /*=====================================================*/
   
   BreakFlag = CLIPS_FALSE;
   
   /*====================================================*/
   /* If the return command was issued, then return that */
   /* value, otherwise return the symbol FALSE.          */
   /*====================================================*/
   
   if (ReturnFlag == CLIPS_TRUE)
     {
      returnValue->type = theResult.type;
      returnValue->value = theResult.value;
      returnValue->begin = theResult.begin;
      returnValue->end = theResult.end;
     }
   else
     {
      returnValue->type = SYMBOL;
      returnValue->value = CLIPSFalseSymbol;
     }
  }
  
/**********************************************/
/* LoopForCountFunction: CLIPS access routine */
/*   for the loop-for-count function.         */
/**********************************************/
globle VOID LoopForCountFunction(loopResult)
  DATA_OBJECT_PTR loopResult;
  {
   DATA_OBJECT arg_ptr;
   long iterationEnd;
   LOOP_COUNTER_STACK *tmpCounter;

   tmpCounter = get_struct(loopCounterStack);
   tmpCounter->loopCounter = 0L;
   tmpCounter->nxt = LoopCounterStack;
   LoopCounterStack = tmpCounter;
   if (ArgTypeCheck("loop-for-count",1,INTEGER,&arg_ptr) == CLIPS_FALSE)
     {
      loopResult->type = SYMBOL;
      loopResult->value = CLIPSFalseSymbol;
      LoopCounterStack = tmpCounter->nxt;
      rtn_struct(loopCounterStack,tmpCounter);
      return;
     }
   tmpCounter->loopCounter = DOToLong(arg_ptr);
   if (ArgTypeCheck("loop-for-count",2,INTEGER,&arg_ptr) == CLIPS_FALSE)
     {
      loopResult->type = SYMBOL;
      loopResult->value = CLIPSFalseSymbol;
      LoopCounterStack = tmpCounter->nxt;
      rtn_struct(loopCounterStack,tmpCounter);
      return;
     }
   iterationEnd = DOToLong(arg_ptr);
   while ((tmpCounter->loopCounter <= iterationEnd) &&
          (HaltExecution != CLIPS_TRUE))
     {
      if ((BreakFlag == CLIPS_TRUE) || (ReturnFlag == CLIPS_TRUE))
        break;
      CurrentEvaluationDepth++;
      RtnUnknown(3,&arg_ptr);
      CurrentEvaluationDepth--;
      if (ReturnFlag == CLIPS_TRUE)
        { PropagateReturnValue(&arg_ptr); }
      PeriodicCleanup(CLIPS_FALSE,CLIPS_TRUE);
      if ((BreakFlag == CLIPS_TRUE) || (ReturnFlag == CLIPS_TRUE))
        break;
      tmpCounter->loopCounter++;
     }

   BreakFlag = CLIPS_FALSE;
   if (ReturnFlag == CLIPS_TRUE)
     {
      loopResult->type = arg_ptr.type;
      loopResult->value = arg_ptr.value;
      loopResult->begin = arg_ptr.begin;
      loopResult->end = arg_ptr.end; 
     }
   else
     {
      loopResult->type = SYMBOL;
      loopResult->value = CLIPSFalseSymbol;
     }
   LoopCounterStack = tmpCounter->nxt;
   rtn_struct(loopCounterStack,tmpCounter);
  }

/************************************************/
/* GetLoopCount                                 */
/************************************************/
globle long GetLoopCount()
  {
   int depth;
   LOOP_COUNTER_STACK *tmpCounter;
   
   depth = ValueToInteger(GetFirstArgument()->value);
   tmpCounter = LoopCounterStack;
   while (depth > 0)
     {
      tmpCounter = tmpCounter->nxt;
      depth--;
     }
   return(tmpCounter->loopCounter);
  }

/************************************/
/* IfFunction: CLIPS access routine */
/*   for the if function.           */
/************************************/
globle VOID IfFunction(returnValue)
  DATA_OBJECT_PTR returnValue;
  {
   int numArgs;

   /*============================================*/
   /* Check for the correct number of arguments. */
   /*============================================*/
   
   if ((numArgs = ArgRangeCheck("if",2,3)) == -1)
     {
      returnValue->type = SYMBOL;
      returnValue->value = CLIPSFalseSymbol;
      return;
     }

   /*=========================*/
   /* Evaluate the condition. */
   /*=========================*/
   
   RtnUnknown(1,returnValue);
   if ((BreakFlag == CLIPS_TRUE) || (ReturnFlag == CLIPS_TRUE))
     { return; }

   /*=========================================*/
   /* If the condition evaluated to FALSE and */
   /* an "else" portion exists, evaluate it   */
   /* and return the value.                   */
   /*=========================================*/

   if ((returnValue->value == CLIPSFalseSymbol) &&
       (returnValue->type == SYMBOL) &&
       (numArgs == 3))
     {
      RtnUnknown(3,returnValue);
      return;
     }
   
   /*===================================================*/
   /* Otherwise if the symbol evaluated to a non-FALSE  */
   /* value, evaluate the "then" portion and return it. */
   /*===================================================*/