CompositeSubtractNode.cpp

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/* -*- C++ -*- */
#ifndef _SUBTRACT_NODE_CPP_
#define _SUBTRACT_NODE_CPP_

#ifndef _MADARA_NO_KARL_

#include "madara/expression/ComponentNode.h"
#include "madara/expression/Visitor.h"
#include "madara/expression/CompositeBinaryNode.h"
#include "madara/expression/CompositeSubtractNode.h"
#include "madara/expression/LeafNode.h"

madara::expression::CompositeSubtractNode::CompositeSubtractNode (
  logger::Logger & logger, ComponentNode *left, ComponentNode *right)
: madara::expression::CompositeBinaryNode (logger, left, right)
{    
}

// Dtor
madara::expression::CompositeSubtractNode::~CompositeSubtractNode (void)
{
}

madara::knowledge::KnowledgeRecord
madara::expression::CompositeSubtractNode::item (void) const
{
  return knowledge::KnowledgeRecord ("-");
}

madara::knowledge::KnowledgeRecord
madara::expression::CompositeSubtractNode::prune (bool & can_change)
{
  bool left_child_can_change = false;
  bool right_child_can_change = false;
  madara::knowledge::KnowledgeRecord left_value;
  madara::knowledge::KnowledgeRecord right_value;

  if (this->left_)
  {
    left_value = this->left_->prune (left_child_can_change);
    if (!left_child_can_change && dynamic_cast <LeafNode *> (left_) == 0)
    {
      delete this->left_;
      this->left_ = new LeafNode (*(this->logger_), left_value);
    }
  }
  else
  {
    madara_logger_ptr_log (logger_, logger::LOG_ERROR,
      "madara::expression::CompositeSubtractNode: "
      "KARL COMPILE ERROR: Subtraction has no left expression\n");

    throw KarlException ("madara::expression::CompositeSubtractNode: "
      "KARL COMPILE ERROR: "
      "Node has no left expression\n"); 
  }

  if (this->right_)
  {
    right_value = this->right_->prune (right_child_can_change);
    if (!right_child_can_change && dynamic_cast <LeafNode *> (right_) == 0)
    {
      delete this->right_;
      this->right_ = new LeafNode (*(this->logger_), right_value);
    }
  }
  else
  {
    madara_logger_ptr_log (logger_, logger::LOG_ERROR,
      "madara::expression::CompositeSubtractNode: "
      "KARL COMPILE ERROR: Subtraction has no right expression\n");

    throw KarlException ("madara::expression::CompositeSubtractNode: "
      "KARL COMPILE ERROR: "
      "Node has no right expression\n"); 
  }

  can_change = left_child_can_change || right_child_can_change;

  return knowledge::KnowledgeRecord (left_value - right_value);
}

madara::knowledge::KnowledgeRecord 
madara::expression::CompositeSubtractNode::evaluate (
  const madara::knowledge::KnowledgeUpdateSettings & settings)
{
  knowledge::KnowledgeRecord left = left_->evaluate (settings);
  knowledge::KnowledgeRecord right = right_->evaluate (settings);
  
  madara_logger_ptr_log (logger_, logger::LOG_MAJOR,
    "madara::expression::CompositeSubtractNode:evaluate: "
    "%s - %s\n", left.to_string ().c_str (),
    right.to_string ().c_str ());

  // note we do not check if left or right are null. This should be checked
  // during prune or an earlier phase. Evaluate is all about speed.
  return left - right;
}

// accept a visitor
void 
madara::expression::CompositeSubtractNode::accept (Visitor &visitor) const
{
  visitor.visit (*this);
}

#endif // _MADARA_NO_KARL_

#endif /* _SUBTRACT_NODE_CPP_ */