/// <summary>
/// Adds a new event to the state machine.
/// </summary>
/// <param name="eventname"></param>
/// <returns></returns>
public Event AddEvent(string eventname)
{
Event e;
if (!_events.TryGetValue(eventname, out e))
{
_events[eventname] = e = new Event(eventname);
}
return e;
}
/// <summary>
/// Emits code for a single event handler.
/// </summary>
/// <param name="e"></param>
private void EmitEventHandler(Event e)
{
BeginHandler(e);
PrepareTransitionSet(e);
// use gate converter to schedule condition evaluation
ConvertConditions(e);
// stage 0: preconditions and LEAVE handlers
_guards.AddLeaveEffects(_effectsbefore);
_guards.AddEnterEffects(_effectsafter);
AddTriggerEffects(e.Triggers);
foreach(var t in e.Triggers)
{
var c = _gc.ConvertToGate(0, t.PreCondition);
_gc.Schedule(c);
}
_effectsbefore.Schedule(_gc);
_effectsafter.Schedule(_gc);
// code output: precondition labels
EmitCodeLabels(0);
// pre-effects
if (!_effectsbefore.IsEmpty)
{
Writer.AppendComment();
Writer.AppendComment("state exit handler effects");
EmitEffects(_effectsbefore.GetEffectConditions());
}
// emit state transition code
EmitTriggerStateChange(_writer, e.Triggers);
// stage 1: postconditions and other handlers.
_gc.SetNextStage();
// code output: postcondition labels
EmitCodeLabels(1);
// post-effects
if (!_effectsafter.IsEmpty)
{
Writer.AppendComment();
Writer.AppendComment("state entry handler effects");
EmitEffects(_effectsafter.GetEffectConditions());
}
EndHandler();
}
private void PrepareTransitionSet(Event e)
{
// next state inference ...
_tset = new TransitionSet();
_tset.AddRange(e.Triggers
.SelectMany(t => t.Transitions)
);
// set of modified variable indexes
_modified = e.Triggers
.SelectMany(t => t.ModifiedVariables)
.Distinct()
.Select(z => z.Index).ToList();
}
private void BeginHandler(Event e)
{
// code generation start here
EmitHandlerHeader(e.Name);
EmitEnterBlock();
_gc = new GateConverter();
// process labels before they are added ...
_gc.OnBeforeAddLabel = EvaluateCodeLabelBefore;
_guards = new GuardCollection();
_effectsbefore = new EffectsCollection();
_effectsafter = new EffectsCollection();
}
private void ConvertConditions(Event e)
{
var c = new TriggerTermCollection<bool>(true);
foreach (var t in e.Triggers)
{
c.Add(t);
}
foreach (var t in e.Triggers)
{
foreach (var g in t.Guards)
{
_guards.AddGuard(t, g);
}
}
}
protected abstract void EmitSwitchCaseLabel(Event e);
protected abstract void EmitHandlerInvocation(Event e);
protected override void EmitSwitchCaseLabel(Event e)
{
var caselabel = Parameters.EventTypeName + "." + e.Name;
Writer.AppendLine("case " + caselabel + ":");
}
protected override void EmitHandlerInvocation(Event e)
{
Writer.AppendLine(e.Name + "_Handler();");
Writer.AppendLine("break;");
Writer.AppendLine();
}
public Trigger(Event e, ICondition c)
: base(e.Name, c)
{
Event = e;
}
