/// <summary>
/// Creates a version of the current
/// <see cref="NFAState{TCheck, TNFAState, TDFAState, TSourceElement}"/> which is
/// deterministic by creating a left-side union on elements
/// which overlap on their <typeparamref name="TCheck"/>
/// transition requirements.
/// </summary>
/// <returns>A new <typeparamref name="TDFAState"/>
/// instance which represents the current automation
/// in a deterministic manner.</returns>
public TDFAState DeterminateAutomata()
{
DFAEntryTable entrySet = new DFAEntryTable(this.GetDFAState);
TDFAState result = GetRootDFAState();
if (!this.IgnoreSources)
{
ReplicateSourcesToAlt <TDFAState, TDFAState>(result);
}
result.IsReductionSite = this.IsReductionSite;
ReplicateStateTransitions(result, this.OutTransitions, entrySet);
result.IsEdge = this.IsEdge;
return(result);
}
private void ReplicateStateTransitions(TDFAState result, IFiniteAutomataMultiTargetTransitionTable <TCheck, TNFAState> table, DFAEntryTable entrySet)
{
/* *
* For every transition on the current transition table,
* construct a new version of the target state via merging
* the full transition tables of the NFA states.
* *
* This process is repeated with this merged table.
* */
foreach (var transition in table.Keys)
{
var set = table[transition].Distinct().ToList();
if (entrySet.ContiansEntryFor(transition, set))
{
result.MoveTo(transition, entrySet[transition][set].DFA);
}
else
{
var newElement = entrySet.Add(transition, set);
FiniteAutomataMultiTargetTransitionTable <TCheck, TNFAState> mergedTable = new FiniteAutomataMultiTargetTransitionTable <TCheck, TNFAState>();
foreach (var subState in set)
{
foreach (var subTransition in subState.OutTransitions.Keys.ToArray())
{
mergedTable.Add(subTransition, subState.OutTransitions[subTransition]);
}
}
var curDFA = newElement.DFA;
result.MoveTo(transition, curDFA);
foreach (var item in set)
{
if (!item.IgnoreSources)
{
item.ReplicateSourcesToAlt <TDFAState, TDFAState>(curDFA);
}
}
curDFA.ReduceSources();
ReplicateStateTransitions(newElement.DFA, mergedTable, entrySet);
}
}
}
