/**
* This method loads the system variables is necessary.
*/
private function loadSystemVariables()
{
// Install the math variables.
if ($this->loadMathVariables) {
// Add the two math variables.
$e = new Double(Math::E);
$pi = new Double(Math::PI);
$this->putVariable("E", $e->toString());
$this->putVariable("PI", $pi->toString());
}
}
/**
* Evaluates the operands for this tree using the operator and the unary
* operator.
*
* @param wrapStringFunctionResults
* Indicates if the results from functions that return strings
* should be wrapped in quotes. The quote character used will be
* whatever is the current quote character for this object.
*
* @exception EvaluateException
* Thrown is an error is encountered while processing the
* expression.
*
* @return String
*/
public function evaluate($wrapStringFunctionResults)
{
$rtnResult = null;
// Get the left operand.
$leftResultString = null;
$leftResultDouble = null;
if ($this->leftOperand instanceof ExpressionTree) {
$leftResultString = $this->leftOperand->evaluate($wrapStringFunctionResults);
try {
$leftResultDouble = new Double($leftResultString);
$leftResultString = null;
} catch (NumberFormatException $exception) {
$leftResultDouble = null;
}
} else {
if ($this->leftOperand instanceof ExpressionOperand) {
$leftExpressionOperand = $this->leftOperand;
$leftResultString = $leftExpressionOperand->getValue();
$leftResultString = $this->evaluator->replaceVariables($leftResultString);
// Check if the operand is a string or not. If it is not a string,
// then it must be a number.
if (!$this->evaluator->isExpressionString($leftResultString)) {
try {
$leftResultDouble = new Double($leftResultString);
$leftResultString = null;
} catch (NumberFormatException $nfe) {
throw new EvaluationException("Expression is invalid.", $nfe);
}
if ($leftExpressionOperand->getUnaryOperator() != null) {
$leftResultDouble = new Double($leftExpressionOperand->getUnaryOperator()->evaluate($leftResultDouble));
}
} else {
if ($leftExpressionOperand->getUnaryOperator() != null) {
throw new EvaluationException("Invalid operand for unary operator.");
}
}
} else {
if ($this->leftOperand instanceof ParsedFunction) {
$parsedFunction = $this->leftOperand;
$function = $parsedFunction->getFunction();
$arguments = $parsedFunction->getArguments();
$arguments = $this->evaluator . replaceVariables($arguments);
if ($this->evaluator->getProcessNestedFunctions()) {
$arguments = $this->evaluator->processNestedFunctions($arguments);
}
try {
$functionResult = $function->execute($this->evaluator, $arguments);
$leftResultString = $functionResult->getResult();
if ($functionResult->getType() == FunctionConstants::FUNCTION_RESULT_TYPE_NUMERIC) {
$resultDouble = new Double($leftResultString);
// Process a unary operator if one exists.
if ($parsedFunction->getUnaryOperator() != null) {
$resultDouble = new Double($parsedFunction->getUnaryOperator()->evaluate($resultDouble . getValue()));
}
// Get the final result.
$leftResultString = $resultDouble . toString();
} else {
if ($functionResult->getType() == FunctionConstants::FUNCTION_RESULT_TYPE_STRING) {
// The result must be a string result.
if ($wrapStringFunctionResults) {
$leftResultString = $this->evaluator->getQuoteCharacter() . $leftResultString . $this->evaluator->getQuoteCharacter();
}
if ($parsedFunction->getUnaryOperator() != null) {
throw new EvaluationException("Invalid operand for unary operator.");
}
}
}
} catch (FunctionException $fe) {
throw new EvaluationException($fe->getMessage(), $fe);
}
if (!$this->evaluator->isExpressionString($leftResultString)) {
try {
$leftResultDouble = new Double($leftResultString);
$leftResultString = null;
} catch (NumberFormatException $nfe) {
throw new EvaluationException("Expression is invalid.", $nfe);
}
}
} else {
if ($this->leftOperand != null) {
throw new EvaluationException("Expression is invalid.");
}
}
}
}
// Get the right operand.
$rightResultString = null;
$rightResultDouble = null;
if ($this->rightOperand instanceof ExpressionTree) {
$rightResultString = $this->rightOperand->evaluate($wrapStringFunctionResults);
try {
$rightResultDouble = new Double($rightResultString);
$rightResultString = null;
} catch (NumberFormatException $exception) {
$rightResultDouble = null;
}
} else {
if ($this->rightOperand instanceof ExpressionOperand) {
$rightExpressionOperand = $this->rightOperand;
$rightResultString = $this->rightOperand->getValue();
$rightResultString = $this->evaluator->replaceVariables($rightResultString);
// Check if the operand is a string or not. If it not a string,
// then it must be a number.
if (!$this->evaluator->isExpressionString($rightResultString)) {
try {
$rightResultDouble = new Double($rightResultString);
$rightResultString = null;
} catch (NumberFormatException $nfe) {
throw new EvaluationException("Expression is invalid.", $nfe);
}
if ($rightExpressionOperand->getUnaryOperator() != null) {
$rightResultDouble = new Double($rightExpressionOperand->getUnaryOperator()->evaluate($rightResultDouble));
}
} else {
if ($rightExpressionOperand->getUnaryOperator() != null) {
throw new EvaluationException("Invalid operand for unary operator.");
}
}
} else {
if ($this->rightOperand instanceof ParsedFunction) {
$parsedFunction = $this->rightOperand;
$function = $parsedFunction->getFunction();
$arguments = $parsedFunction->getArguments();
$arguments = $this->evaluator->replaceVariables($arguments);
if ($this->evaluator->getProcessNestedFunctions()) {
$arguments = $this->evaluator->processNestedFunctions($arguments);
}
try {
$functionResult = $function->execute($this->evaluator, $arguments);
$rightResultString = $functionResult->getResult();
if ($functionResult->getType() == FunctionConstants::FUNCTION_RESULT_TYPE_NUMERIC) {
$resultDouble = new Double($rightResultString);
// Process a unary operator if one exists.
if ($parsedFunction->getUnaryOperator() != null) {
$resultDouble = new Double($parsedFunction->getUnaryOperator()->evaluate($resultDouble->getValue()));
}
// Get the final result.
$rightResultString = $resultDouble->toString();
} else {
if ($functionResult->getType() == FunctionConstants::FUNCTION_RESULT_TYPE_STRING) {
// The result must be a string result.
if ($wrapStringFunctionResults) {
$rightResultString = $this->evaluator->getQuoteCharacter() . $rightResultString . $this->evaluator->getQuoteCharacter();
}
if ($parsedFunction->getUnaryOperator() != null) {
throw new EvaluationException("Invalid operand for unary operator.");
}
}
}
} catch (FunctionException $fe) {
throw new EvaluationException($fe . getMessage(), $fe);
}
if (!$this->evaluator->isExpressionString($rightResultString)) {
try {
$rightResultDouble = new Double($rightResultString);
$rightResultString = null;
} catch (NumberFormatException $nfe) {
throw new EvaluationException("Expression is invalid.", $nfe);
}
}
} else {
if ($this->rightOperand == null) {
// Do nothing.
} else {
throw new EvaluationException("Expression is invalid.");
}
}
}
}
// Evaluate the the expression.
if ($leftResultDouble != null && $rightResultDouble != null) {
$doubleResult = $this->operator->evaluate($leftResultDouble, $rightResultDouble);
if ($this->getUnaryOperator() != null) {
$doubleResult = $this->getUnaryOperator()->evaluate($doubleResult);
}
$rtnResult = new Double($doubleResult);
$rtnResult = $rtnResult->toString();
} else {
if ($leftResultString != null && $rightResultString != null) {
$rtnResult = $this->operator->evaluate($leftResultString, $rightResultString);
} else {
if ($leftResultDouble != null && $rightResultDouble == null) {
$doubleResult = new Double(-1);
if ($this->unaryOperator != null) {
$doubleResult = $this->unaryOperator->evaluate($leftResultDouble);
} else {
// Do not allow numeric (left) and
// string (right) to be evaluated together.
throw new EvaluationException("Expression is invalid.");
}
$rtnResult = new Double($doubleResult);
$rtnResult = $rtnResult->toString();
} else {
throw new EvaluationException("Expression is invalid.");
}
}
}
return $rtnResult;
}
