public void GetAndEvaluateWhileExpression()
{
WhileExpression expression = WhileExpression.Instance;
Assert.IsNotNull(expression);
Machine machine = new Machine();
List <Expression> listcond = new List <Expression>();
listcond.Add(DupExpression.Instance);
listcond.Add(new IntegerExpression(0));
listcond.Add(EqualsExpression.Instance);
listcond.Add(NotExpression.Instance);
List <Expression> listblock = new List <Expression>();
listblock.Add(IntegerDecrementOperation.Instance);
CompositeExpression cond = new CompositeExpression(listcond);
CompositeExpression block = new CompositeExpression(listblock);
machine.Push(10);
machine.Push(block);
machine.Push(cond);
expression.Evaluate(machine);
Assert.AreEqual(1, machine.StackCount);
Assert.IsInstanceOfType(machine.Top(), typeof(int));
Assert.AreEqual(0, machine.Pop());
}
public void ExecuteSimpleWhileWhenConditionIsTrue()
{
Parser cmdparser = new Parser("a = a + 1");
IExpression body = cmdparser.ParseCommand();
Parser exprparser = new Parser("a < 6");
IExpression expr = exprparser.ParseExpression();
Context context = new Context();
context.SetLocalValue("a", 1);
WhileExpression cmd = new WhileExpression(expr, body);
Assert.IsNull(cmd.Evaluate(context));
Assert.AreEqual(6, context.GetValue("a"));
}