internal DFATable ToDFATable()
{
var dfa = new DFATable();
var mergedStates = new List <HashSet <Node> >();
foreach (var entry in this._relations)
{
if (entry.Value != Relation.Equivalent)
{
continue;
}
var pair = entry.Key;
bool merged = false;
foreach (var mergedState in mergedStates)
{
if (mergedState.Contains(pair.A) || mergedState.Contains(pair.B))
{
mergedState.Add(pair.A);
mergedState.Add(pair.B);
merged = true;
break;
}
}
if (!merged)
{
mergedStates.Add(new HashSet <Node>()
{
pair.A, pair.B
});
}
}
// Create new states.
var mergedStateMap = new Dictionary <Node, Node>();
foreach (var mergedState in mergedStates)
{
var node = dfa.CreateNode();
foreach (var state in mergedState)
{
node.UnionTags(state.GetTags());
mergedStateMap[state] = node;
}
// Merged states will not have conflicting values for IsFinal.
node.IsFinal = mergedState.First().IsFinal;
}
var symbols = this._dfa.GetAllPossibleSymbols();
foreach (var mergedState in mergedStates)
{
foreach (var symbol in symbols)
{
Debug.Assert(symbol != NFATable.Epsilon, $"DFATable cannot contain epsilon transition.");
var resultingStates = this._dfa.ApplyTransition(mergedState, symbol);
var source = mergedStateMap[mergedState.First()];
var destination = mergedStateMap[resultingStates.First()];
dfa.AddTransition(source, destination, symbol);
}
}
dfa.StartState = mergedStateMap[this._dfa.StartState];
return(dfa);
}
public DFAMinimizationTable(DFATable dFATable)
{
this._dfa = dFATable;
this._relations = new Dictionary <NodePair, Relation>();
}