private NumericalNode Term()
{
NumericalNode result = Factor();
Token token;
while (CurrentToken.Type != TokenType.EOF)
{
token = CurrentToken;
if (CurrentToken.Type == TokenType.TIMES)
{
Eat(TokenType.TIMES);
}
else if (CurrentToken.Type == TokenType.INTEGER_DIV)
{
Eat(TokenType.INTEGER_DIV);
}
else if (CurrentToken.Type == TokenType.FLOAT_DIV)
{
Eat(TokenType.FLOAT_DIV);
}
else
{
break;
}
result = new BinaryOperator(result, token, Factor());
}
return(result);
}
public dynamic VisitBinaryOperator(NumericalNode node)
{
dynamic result;
var TmpNode = node as BinaryOperator;
switch (TmpNode.Op.Type)
{
case TokenType.ADD:
result = Visit(TmpNode.Left) + Visit(TmpNode.Right);
break;
case TokenType.SUBTRACT:
result = Visit(TmpNode.Left) - Visit(TmpNode.Right);
break;
case TokenType.TIMES:
result = Visit(TmpNode.Left) * Visit(TmpNode.Right);
break;
case TokenType.INTEGER_DIV:
result = Visit(TmpNode.Left) / Visit(TmpNode.Right);
break;
case TokenType.FLOAT_DIV:
result = Visit(TmpNode.Left) / Visit(TmpNode.Right);
break;
default:
throw new Exception("Unrecognised op");
}
return(result);
}
public dynamic Visit(NumericalNode node)
{
var nodeName = node.GetType().Name;
var visitorMethod = this.GetType().GetMethod("Visit" + nodeName);
return(visitorMethod.Invoke(this, new object[] { node }));
}
public dynamic VisitNum(NumericalNode node)
{
var num = node as Num;
if (num.Value.Value.Contains('.'))
{
return(float.Parse(num.Value.Value));
}
return(int.Parse((node as Num).Value.Value));
}
public int VisitUnaryOperator(NumericalNode node)
{
var tmpNode = node as UnaryOperator;
if (tmpNode.Op.Type == TokenType.ADD)
{
return(Visit(tmpNode.Node));
}
else if (tmpNode.Op.Type == TokenType.SUBTRACT)
{
return(-Visit(tmpNode.Node));
}
else
{
throw new Exception("Runtime Error: Could not interpret unary operator");
}
}
private NumericalNode Expr()
{
NumericalNode result = Term();
Token token;
while (CurrentToken.Type == TokenType.ADD || CurrentToken.Type == TokenType.SUBTRACT)
{
token = CurrentToken;
if (CurrentToken.Type == TokenType.ADD)
{
Eat(TokenType.ADD);
}
else if (CurrentToken.Type == TokenType.SUBTRACT)
{
Eat(TokenType.SUBTRACT);
}
result = new BinaryOperator(result, token, Term());
}
return(result);
}
public int VisitVariable(NumericalNode node)
{
var varNode = node as Variable;
return(GlobalScope[varNode.Value.Value]);
}
public Assignment(ASTNode Left, Token Op, NumericalNode Right)
{
this.Left = Left;
this.Right = Right;
this.Op = Op;
}
public UnaryOperator(NumericalNode node, Token op)
{
Node = node;
Op = op;
}
public BinaryOperator(NumericalNode Left, Token Op, NumericalNode Right)
{
this.Left = Left;
this.Right = Right;
this.Op = Op;
}
