IfInstruction.cpp

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/* Copyright (c) 2005-2009 Rexx Language Association. All rights reserved.    */
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/******************************************************************************/
/* REXX Translator                                                            */
/*                                                                            */
/* Primitive If Parse Class                                                   */
/*                                                                            */
/******************************************************************************/
#include <stdlib.h>
#include "RexxCore.h"
#include "RexxActivation.hpp"
#include "IfInstruction.hpp"
#include "Token.hpp"
 
 
RexxInstructionIf::RexxInstructionIf(
    RexxObject *_condition,            /* conditional expression            */
    RexxToken  *token)                 /* terminating THEN token            */
/******************************************************************************/
/* Function:  Complete IF instruction initialization                          */
/******************************************************************************/
{
  SourceLocation location;             /* clause token location             */
 
                                       /* save the condition                */
  OrefSet(this, this->condition, _condition);
  location = token->getLocation();     /* get the token location info       */
                                       /* update the end location           */
  this->setEnd(location.getLineNumber(), location.getOffset());
}
 
void RexxInstructionIf::setEndInstruction(
    RexxInstructionEndIf *end_target)  /* targer for the false branch       */
/******************************************************************************/
/* Function:  Set the location for the false branch of the IF instruction     */
/******************************************************************************/
{
                                       /* save the end location             */
  OrefSet(this, this->else_location, end_target);
}
 
void RexxInstructionIf::live(size_t liveMark)
/******************************************************************************/
/* Function:  Normal garbage collection live marking                          */
/******************************************************************************/
{
  memory_mark(this->nextInstruction);  /* must be first one marked          */
  memory_mark(this->condition);
  memory_mark(this->else_location);
}
 
 
void RexxInstructionIf::liveGeneral(int reason)
/******************************************************************************/
/* Function:  Generalized object marking                                      */
/******************************************************************************/
{
                                       /* must be first one marked          */
  memory_mark_general(this->nextInstruction);
  memory_mark_general(this->condition);
  memory_mark_general(this->else_location);
}
 
void RexxInstructionIf::flatten(RexxEnvelope *envelope)
/******************************************************************************/
/* Function:  Flatten an object                                               */
/******************************************************************************/
{
  setUpFlatten(RexxInstructionIf)
 
  flatten_reference(newThis->nextInstruction, envelope);
  flatten_reference(newThis->condition, envelope);
  flatten_reference(newThis->else_location, envelope);
 
  cleanUpFlatten
}
 
void RexxInstructionIf::execute(
    RexxActivation      *context,      /* current activation context        */
    RexxExpressionStack *stack)        /* evaluation stack                  */
/******************************************************************************/
/* Function:  Execute a REXX IF instruction                                   */
/******************************************************************************/
{
    context->traceInstruction(this);     /* trace if necessary                */
                                         /* get the expression value          */
    RexxObject *result = this->condition->evaluate(context, stack);
    context->traceResult(result);        /* trace if necessary                */
 
    /* the comparison methods return either .true or .false, so we */
    /* can to a quick test against those. */
    if (result == TheFalseObject)
    {
        /* we execute the ELSE branch        */
        context->setNext(this->else_location->nextInstruction);
    }
    /* if it is not the True object, we need to perform a fuller */
    /* evaluation of the result. */
    else if (result != TheTrueObject)
    {
        /* is the condition false?           */
        if (!result->truthValue(Error_Logical_value_if))
        {
            /* we execute the ELSE branch        */
            context->setNext(this->else_location->nextInstruction);
        }
    }
    context->pauseInstruction();         /* do debug pause if necessary       */
}