public object VisitUnaryExpr(UnaryExpr expr)
{
var right = Evaluate(expr.Right);
switch (expr.Operator.Type)
{
case TokenType.Bang:
return(!IsTruthy(right));
case TokenType.Minus:
CheckNumberOperand(expr.Operator, right);
return(-(double)right);
}
// unreachable
return(null);
}
public void VisitUnaryExpr(UnaryExpr expr)
{
Resolve(expr.Right);
}
public string VisitUnaryExpr(UnaryExpr expr)
{
return(Parenthesize(expr.Operator.Lexeme, expr.Right));
}