private void EarleyReducer(EarleyItem completed, int setNumber)
{
int position = completed.GetOrignPosition();
EarleySet set = Sets[position];
List <EarleyItem> items = set.GetEarleyItemList();
for (int j = 0; j < items.Count; j++)
{
EarleyItem current = items[j];
Symbol next = current.GetCurrentNextSymbol();
if (next != null && next.Equals(completed.GetRule().GetLeftHandSideOfRule()))
{
EarleyItem newEarleyItem = new EarleyItem(
setNumber,
new DottedRule(current.GetRule(), current.GetRulePosition() + 1),
current.GetOrignPosition()
);
if (current.GetCurrentPrevSymbolList() != null && current.GetCurrentPrevSymbolList().Count > 0)
{
newEarleyItem.AddPredecessorLink(current, position);
}
newEarleyItem.AddReducerLink(completed, position);
AddToSet(newEarleyItem, setNumber, "EarleyReducer");
}
}
}
private void Scanner(EarleyItem current, int setNumber, Char inputSymbol)
{
Symbol nextSymbol = current.GetCurrentNextSymbol();
if (nextSymbol != null && nextSymbol.Equals(inputSymbol.ToString()))
{
EarleyItem newEarleyItem = new EarleyItem(
setNumber + 1,
new DottedRule(current.GetRule(), current.GetRulePosition() + 1),
current.GetOrignPosition()
);
if (newEarleyItem.GetCurrentPrevSymbolList() != null && newEarleyItem.GetCurrentPrevSymbolList().Count > 0)
{
newEarleyItem.AddPredecessorLink(current, setNumber);
}
AddToSet(newEarleyItem, setNumber + 1, "Scanner");
}
}
private void Predictor(EarleyItem current, int setNumber)
{
Symbol sym = current.GetCurrentNextSymbol();
List <Rule> filteredRules = Grammar.GetRulesWithSpecificStartSymbol(sym);
filteredRules.ForEach((Rule r) =>
{
List <Symbol> symList = r.GetRightHandSideOfRule();
if (symList.Count == 1 && Grammar.CheckIsSymbolANullStringSymbol(symList[0]))
{
AddToSet(new EarleyItem(setNumber, new DottedRule(current.GetRule(), current.GetRulePosition() + 1), setNumber), setNumber, "Predictor");
}
else
{
EarleyItem ei = new EarleyItem(setNumber, r, setNumber);
AddToSet(ei, setNumber, "Predictor");
LeoMemoization(ei, setNumber);
}
});
}
private void RunMarpa(String input, int fromPosition)
{
for (int i = fromPosition; i <= input.Length; i++)
{
EarleySet set = Sets[i];
List <EarleyItem> items = set.GetEarleyItemList();
for (int j = 0; j < items.Count; j++)
{
EarleyItem current = items[j];
if (current.IsCompleted())
{
Completer(current, i);
}
else
{
bool condition = Grammar.DoesBelongToTerminals(current.GetCurrentNextSymbol());
if (!condition)
{
Predictor(current, i);
}
else if (input.Length > i)
{
Scanner(current, i, input[i]);
}
}
}
if (i + 1 < Sets.Count && Sets[i + 1].GetEarleyItemList().Count == 0)
{
errorHandler.AddNewError(ErrorCode.UNRECOGNISED_SYMBOL, input[i], i);
return;
}
}
}