/// <summary>
/// Merge current expression with previous expression and the new operand just got before current expression
/// </summary>
/// <param name="prevExpression"></param>
/// <param name="curExpression"></param>
/// <param name="newOperand"></param>
/// <param name="errMsg"></param>
/// <returns></returns>
public static bool MergeExpressions(ArithmeticExpression <ICalculator> prevExpression, ref ArithmeticExpression <ICalculator> curExpression, ref ArithmeticOperand <ICalculator> newOperand, ref string errMsg)
{
if (prevExpression == null || curExpression == null)
{
errMsg += "prevExpression is null or curExpression is null in MergeExpressions.";
return(false);
}
if (prevExpression.Priority() < curExpression.Priority())
{
curExpression.AddOperand(newOperand);
prevExpression.AddOperand(curExpression);
}
else if (prevExpression.Priority() > curExpression.Priority())
{
prevExpression.AddOperand(newOperand);
if (prevExpression.ParentExpression != null && prevExpression.ParentExpression.Priority() == curExpression.Priority())
{
prevExpression.ParentExpression.Operators.AddRange(curExpression.Operators);
prevExpression.ParentExpression.AddOperands(curExpression.Operands);
curExpression = prevExpression.ParentExpression;
}
else
{
curExpression.AddOperand(prevExpression);
}
}
else
{
prevExpression.AddOperand(newOperand);
prevExpression.Operators.AddRange(curExpression.Operators);
prevExpression.AddOperands(curExpression.Operands);
curExpression = prevExpression;
}
newOperand = null;
return(true);
}