private Evaluation PerformEvaluate(ParseTreeNode node)
{
switch (node.Term.Name)
{
case "BinaryExpression":
var leftNode = node.ChildNodes[0];
var opNode = node.ChildNodes[1];
var rightNode = node.ChildNodes[2];
Evaluation left = PerformEvaluate(leftNode);
Evaluation right = PerformEvaluate(rightNode);
BinaryOperation op = BinaryOperation.Add;
switch (opNode.Term.Name)
{
case "+":
op = BinaryOperation.Add;
break;
case "-":
op = BinaryOperation.Sub;
break;
case "*":
op = BinaryOperation.Mul;
break;
case "/":
op = BinaryOperation.Div;
break;
}
return(new BinaryEvaluation(left, right, op));
case "Number":
var value = Convert.ToSingle(node.Token.Text);
return(new ConstantEvaluation(value));
}
throw new InvalidOperationException($"Unrecognizable term {node.Term.Name}.");
}
public BinaryEvaluation(Evaluation left, Evaluation right, BinaryOperation oper)
{
this.left = left;
this.right = right;
this.oper = oper;
}
