public IExpression MakeExpression(string expressionString)
{
var infixTokens = expressionTokenizer.Tokenize(expressionString);
if (infixTokens.Count == 0)
{
return(null);
}
var postfixTokens = infixToPostfixConverter.Convert(infixTokens);
var nodeStack = new Stack <ExpressionNode>();
nodeStack.Push(expressionNodeFactory.MakeNode(postfixTokens[0]));
for (int i = 1; i < postfixTokens.Count; i++)
{
var node = expressionNodeFactory.MakeNode(postfixTokens[i]);
if (node is OperatorNode operatorNode)
{
for (int j = operatorNode.ChildCount - 1; j >= 0; j--)
{
operatorNode.SetChild(nodeStack.Pop(), j);
}
}
nodeStack.Push(node);
}
return(new Expression(nodeStack.Pop()));
}
