static public bool CanTransition(CookPasta from, CookPasta to)
{
switch (from)
{
case CookPasta.BoilWater:
return(to == CookPasta.AddPasta || to == CookPasta.AddSalt);
case CookPasta.AddPasta:
return(to == CookPasta.AddSalt || to == CookPasta.Stir);
case CookPasta.AddSalt:
return(to == CookPasta.AddPasta);
case CookPasta.Stir:
return(to == CookPasta.Strain);
case CookPasta.Strain:
return(to == CookPasta.Eat);
case CookPasta.Eat:
return(false);
default:
throw CodeContractsHelpers.ThrowIfReached <WrongWayOfDoingPasta>("missing case");
}
}
static public void EatAfterStir(CookPasta unknownStep)
{
var init = CookPasta.Stir;
var next = CanTransition(init, unknownStep);
Contract.Assert(next); // note in this example we ask for "next" instead of "not next" as in the example above
}
static public void StrainIsFinal(CookPasta someOtherState)
{
var next = CanTransition(CookPasta.Strain, someOtherState);
Contract.Assert(!next, "We cannot prove it, as it is false");
}
static public void EatingIsFinal(CookPasta someOtherState)
{
var next = CanTransition(CookPasta.Eat, someOtherState);
Contract.Assert(!next, "Once you eat your pasta, nothing more left to do");
}
static public void BoilWaterIsInitial(CookPasta someState)
{
var next = CanTransition(someState, CookPasta.BoilWater);
Contract.Assert(!next, "there is no way to transition to boiling water");
}
static public bool IsTerminal(CookPasta state)
{
return(state == CookPasta.Eat);
}
static public bool IsInitial(CookPasta state)
{
return(state == CookPasta.BoilWater);
}
