public void Print(AdditionExpression ae, StringBuilder sb)
{
sb.Append("(");
Print((dynamic)ae.Left, sb);
sb.Append("+");
Print((dynamic)ae.Right, sb);
sb.Append(")");
}
public override void Visit(AdditionExpression ae)
{
sb.Append("(");
ae.LHS.Accept(this);
sb.Append("+");
ae.RHS.Accept(this);
sb.Append(")");
}
public void SimpleAddition()
{
var simple = new AdditionExpression(new Value(2), new Value(3));
var ep = new ExpressionPrinter();
ep.Visit(simple);
Assert.That(ep.ToString(), Is.EqualTo("(2+3)"));
}
public void Visit(AdditionExpression ae)
{
sb.Append("(");
ae.left.Accept(this);
sb.Append("+");
ae.right.Accept(this);
sb.Append(")");
}
static void Main(string[] args)
{
var e = new AdditionExpression(
left: new DoubleExpression(1),
right: new AdditionExpression(
left: new DoubleExpression(2),
right: new DoubleExpression(3)
)
);
// INTRUSIVE EXPRESSION PRINTING - NOT VISITOR PATTERN
//var sb = new StringBuilder();
//e.Print(sb);
//Console.WriteLine(sb);
// what is more likely: new type or new operation
// REFLECTION BASED PRINTING - STILL NOT USING VISITOR PATTERN
//var sb = new StringBuilder();
//ExpressionPrinter.Print2(e, sb);
//Console.WriteLine(sb);
// CLASSIC VISITOR
//var ep = new ExpressionPrinter();
//ep.Visit(e);
//Console.WriteLine(ep.ToString());
//var calc = new ExpressionCalculator();
//calc.Visit(e);
//Console.WriteLine($"{ep} = {calc.Result}");
// DYNAMIC VISITOR
var ep = new ExpressionPrinter();
var sb = new StringBuilder();
ep.Print((dynamic)e, sb);
Console.WriteLine(sb);
// disadvantages:
// 1) Performance penalty
// 2) Runtime error on missing visitor
// 3) Problematic w.r.t. inheritance
Console.ReadLine();
}
public void Visit(AdditionExpression ae)
{
ae.left.Accept(this);
var a = Result;
ae.right.Accept(this);
var b = Result;
Result = a + b;
}
void Main(string[] args)
{
Expression e = new AdditionExpression(
new DoubleExpression(1),
new AdditionExpression(
new DoubleExpression(2),
new DoubleExpression(3)));
var ep = new ExpressionPrinter();
var sb = new StringBuilder();
ep.Print((dynamic)e, sb);
Console.WriteLine(sb);
}
public virtual void Visit(AdditionExpression ex)
{
}
public static void Main(string[] args)
{
var e = new AdditionExpression(
new DoubleExpression(1),
new AdditionExpression(
new DoubleExpression(2),
new DoubleExpression(3)));
var ep = new ExpressionPrinter();
ep.Visit(e);
Console.WriteLine(ep);
var calc = new ExpressionCalculator();
calc.Visit(e);
Console.WriteLine($"{ep} = {calc.Result}");
Console.WriteLine("Taxi Visitor!");
CustomerStructure o = new CustomerStructure();
o.Attach(new TaxiCustomer("Andrzej"));
o.Attach(new TaxiCustomer("Seba"));
o.Attach(new TaxiCustomer("Pudzian"));
o.Attach(new RichCustomer("Musk"));
o.Attach(new PoorCustomer("Żul"));
Taxi t1 = new Taxi1();
Taxi t2 = new Taxi2();
o.Accept(t1);
Console.WriteLine();
o.Accept(t2);
Console.WriteLine("Acyclic visitor");
var expression = new AcyclicVisitor.AdditionExpression(
new AcyclicVisitor.DoubleExpression(1),
new AcyclicVisitor.AdditionExpression(
new AcyclicVisitor.DoubleExpression(2),
new AcyclicVisitor.DoubleExpression(3)));
var acyclic_ep = new AcyclicVisitor.ExpressionPrinter();
acyclic_ep.Visit(expression);
Console.WriteLine(acyclic_ep.ToString());
Console.WriteLine();
Console.WriteLine("Code exercise");
var simple = new Coding.Exercise.AdditionExpression(new Coding.Exercise.Value(2), new Coding.Exercise.Value(3));
var exercise_ep = new Coding.Exercise.ExpressionPrinter();
exercise_ep.Visit(simple);
Console.WriteLine(exercise_ep.ToString());
Console.ReadLine();
}
