private MultExpression parseMultExpression()
{
INode firstOperand = parseParamExpression();
if (firstOperand != null)
{
MultExpression node = new MultExpression();
node.Operands.Add(firstOperand);
while (lexer.Token is AsteriskToken || lexer.Token is SlashToken)
{
switch (lexer.Token)
{
case AsteriskToken _:
node.Operators.Add(AsteriskToken.Text);
break;
case SlashToken _:
node.Operators.Add(SlashToken.Text);
break;
}
lexer.NextToken();
node.Operands.Add(parseParamExpression());
}
return(node);
}
else
{
return(null);
}
}
private AddExpression parseExpression()
{
MultExpression firstOperand = parseMultExpression();
if (firstOperand != null)
{
AddExpression node = new AddExpression();
node.Operands.Add(firstOperand);
while (lexer.Token is PlusToken || lexer.Token is MinusToken)
{
switch (lexer.Token)
{
case PlusToken _:
node.Operators.Add(PlusToken.Text);
break;
case MinusToken _:
node.Operators.Add(MinusToken.Text);
break;
}
lexer.NextToken();
node.Operands.Add(parseMultExpression());
}
return(node);
}
else
{
return(null);
}
}
public void Visit(MultExpression multExpr)
{
int operandCntr = 1;
multExpr.Operands[0].Accept(this);
foreach (string oper in multExpr.Operators)
{
multExpr.Operands[operandCntr++].Accept(this);
dynamic rightOper = Environment.PopFromTheStack();
dynamic leftOper = Environment.PopFromTheStack();
if (rightOper.GetType() != leftOper.GetType())
{
throw new ExecutorException("Cannot perform an arithmetic operation on operands of different types");
}
else if (leftOper is TurtleItem || leftOper is TurtleItem)
{
throw new ExecutorException("Cannot perform an arithmetic operation on operands of type Turtle");
}
else if (rightOper is double && rightOper == 0)
{
throw new ExecutorException("Dividing by 0");
}
else if (!(rightOper is double) && !(leftOper is double))
{
throw new ExecutorException("Cannot apply multiplication operator on types different than num");
}
dynamic result = oper switch
{
"*" => leftOper * rightOper,
"/" => leftOper / rightOper,
_ => throw new ExecutorException($"Unknown multiplicative operator {oper}")
};
Environment.PushToTheStack(result);
}
}
public void Visit(MultExpression multExpr)
{
int operandCntr = 1;
multExpr.Operands[0].Accept(this);
foreach (string oper in multExpr.Operators)
{
switch (oper)
{
case "*":
Console.Write("*");
break;
case "/":
Console.Write("/");
break;
}
multExpr.Operands[operandCntr++].Accept(this);
}
}
