private TItemState ComputeClosure(TItemState itemState)
{
List <TransRule> rules = parent.rules;
HashSet <TItem> closure = new HashSet <TItem>(itemState.stateItems);
Queue <TItem> closeless = new Queue <TItem>(itemState.stateItems);
while (closeless.Count != 0)
{
TItem item = closeless.Dequeue();
if (rules[item.ruleNum].body.Count == item.dotPos)
{
continue;
}
TransToken nextToken = rules[item.ruleNum].body[item.dotPos];
for (int i = 0; i < rules.Count; ++i)
{
if (nextToken.token != rules[i].head.token)
{
continue;
}
TItem newItem = new TItem(i, 0);
if (closure.Add(newItem))
{
closeless.Enqueue(newItem);
}
}
}
return(new TItemState(closure));
}
private HashSet <TItemState> FindAllStates()
{
var allTokens = new HashSet <TransToken> {
};
allTokens.UnionWith(parent.nonterms);
allTokens.UnionWith(parent.terms);
var foundStates = new HashSet <TItemState> {
};
var transitionlessItems = new Queue <TItemState> {
};
int stateIdCounter = 0;
// Didn't want to create a variable for one time use
// So, created a variable with reuseable name
// These three lines add initial state kernel [S' -> .S]
// anNtYWNoaW5lcy5zb3VyY2Vmb3JnZS5uZXQ=
TItemState kernelState = new TItemState(new TItem(0, 0));
kernelState.stateId = stateIdCounter++;
foundStates.Add(kernelState);
transitionlessItems.Enqueue(kernelState);
while (transitionlessItems.Count != 0)
{
kernelState = transitionlessItems.Dequeue();
TItemState kernelClosure = ComputeClosure(kernelState);
foreach (TransToken token in allTokens)
{
TItemState newState = Goto(kernelClosure, token);
if (newState.stateItems.Count == 0)
{
continue;
}
kernelState.transitions[token] = newState;
bool f**k = foundStates.Contains(newState);
int ass = newState.GetHashCode();
if (foundStates.TryGetValue(newState, out var oldState))
{
kernelState.transitions[token] = oldState;
}
else
{
newState.stateId = stateIdCounter++;
foundStates.Add(newState);
transitionlessItems.Enqueue(newState);
}
}
}
return(foundStates);
}
public override bool Equals(object obj)
{
if (!(obj is TItemState))
{
return(false);
}
TItemState other = (TItemState)obj;
if (this.stateItems.SetEquals(other.stateItems))
{
return(true);
}
else
{
return(false);
}
}
private TItemState Goto(TItemState itemState, TransToken nextTerm)
{
HashSet <TItem> resultingSet = new HashSet <TItem> {
};
foreach (TItem item in itemState.stateItems)
{
TransRule rule = parent.rules[item.ruleNum];
if (rule.body.Count == item.dotPos)
{
continue;
}
if (rule.body[item.dotPos].token == nextTerm.token)
{
resultingSet.Add(new TItem(item.ruleNum, item.dotPos + 1));
}
}
return(new TItemState(resultingSet));
}
