private bool LeoReducer(EarleyItem completed, int setNumber)
{
int position = completed.GetOrignPosition();
Symbol lhs = completed.GetRule().GetLeftHandSideOfRule();
EarleySet set = Sets[position];
LeoItem transitiveItem = set.FindLeoItemBySymbol(lhs);
if (transitiveItem == null)
{
return(false);
}
EarleyItem newEarleyItem = new EarleyItem(
setNumber,
transitiveItem.GetDottedRule(),
transitiveItem.GetOrignPosition()
);
EarleyItem current = Sets[transitiveItem.GetOrignPosition()].GetEarleyItemList()
.Find(el => el.GetDottedRule().Equals(transitiveItem.GetDottedRule()) && el.GetOrignPosition() == transitiveItem.GetOrignPosition());
if (current.GetCurrentPrevSymbolList() != null && current.GetCurrentPrevSymbolList().Count > 0)
{
newEarleyItem.AddPredecessorLink(current, position);
}
newEarleyItem.AddReducerLink(completed, position);
AddToSet(
newEarleyItem,
setNumber,
"LeoReducer"
);
return(true);
}
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 BuildTree(TreeNode parent, EarleyItem current)
{
current.SetItemIsProcessed();
Symbol lhs = current.GetRule().GetLeftHandSideOfRule();
List <Symbol> prev = current.GetCurrentPrevSymbolList();
int setNumber = current.GetSetNumber();
if (IsEmptyRule(current))
{
if (!parent.DoesChildExists(new TreeNode(lhs, setNumber, setNumber)))
{
parent.AddChild(new TreeNode(_grammar.GetNullStringSymbol(), setNumber, setNumber));
}
}
else if (prev.Count == 1 && IsLastSymbolBeforeDotTerminal(prev))
{
Symbol symBeforeDot = prev[prev.Count - 1];
if (!parent.DoesChildExists(new TreeNode(symBeforeDot, setNumber, setNumber)))
{
parent.AddChild(new TreeNode(symBeforeDot, setNumber - 1, setNumber));
}
}
else if (prev.Count == 1 && IsLastSymbolBeforeDotNonTerminal(prev))
{
Symbol symBeforeDot = prev[prev.Count - 1];
TreeNode newNode = new TreeNode(symBeforeDot, current.GetOrignPosition(), setNumber);
if (!parent.DoesChildExists(newNode))
{
parent.AddChild(newNode);
}
current.GetReducerLinks().ForEach(el =>
{
if (el._label == current.GetOrignPosition() && !el._link.IsItemProcessed())
{
BuildTree(newNode, el._link);
}
});
}
else if (IsLastSymbolBeforeDotTerminal(prev))
{
Symbol symBeforeDot = prev[prev.Count - 1];
TreeNode newNode = new TreeNode(symBeforeDot, setNumber - 1, setNumber);
if (!parent.DoesChildExists(newNode))
{
parent.AddChild(newNode);
}
TreeNode newComplexNode = new TreeNode(
new DottedRule(current.GetRule(), current.GetRulePosition() - 1),
current.GetOrignPosition(),
setNumber - 1
);
if (!parent.DoesChildExists(newComplexNode))
{
parent.AddChild(newComplexNode);
}
current.GetPredecessorLinks().ForEach(link =>
{
if (link._label == setNumber - 1 && !link._link.IsItemProcessed())
{
BuildTree(newComplexNode, link._link);
}
});
}
else if (IsLastSymbolBeforeDotNonTerminal(prev))
{
Symbol symBeforeDot = prev[prev.Count - 1];
current.GetReducerLinks().ForEach(item =>
{
TreeNode newNode = new TreeNode(symBeforeDot, item._label, setNumber);
if (!parent.DoesChildExists(newNode))
{
parent.AddChild(newNode);
}
if (!item._link.IsItemProcessed())
{
BuildTree(newNode, item._link);
}
TreeNode newComplexNode = new TreeNode(
new DottedRule(current.GetRule(), current.GetRulePosition() - 1),
current.GetOrignPosition(),
item._label
);
if (!parent.DoesChildExists(newComplexNode))
{
parent.AddChild(newComplexNode);
}
current.GetPredecessorLinks().ForEach(predItem =>
{
if (!predItem._link.IsItemProcessed())
{
BuildTree(newComplexNode, predItem._link);
}
});
});
}
;
}