public LRItem FindByCore(LR0Item core)
{
foreach (LRItem item in this)
{
if (item.Core == core)
{
return(item);
}
}
return(null);
}
private static int CompareLR0Items(LR0Item x, LR0Item y)
{
if (x.ID < y.ID)
{
return(-1);
}
if (x.ID == y.ID)
{
return(0);
}
return(1);
}
public void AddItem(LR0Item core)
{
//Check if a core had been already added. If yes, simply return
if (!AllCores.Add(core))
{
return;
}
//Create new item, add it to AllItems, InitialItems, ReduceItems or ShiftItems
var item = new LRItem(State, core);
AllItems.Add(item);
if (item.Core.IsFinal)
{
ReduceItems.Add(item);
}
else
{
ShiftItems.Add(item);
}
if (item.Core.IsInitial)
{
InitialItems.Add(item);
}
if (core.IsFinal)
{
return;
}
//Add current term to ShiftTerms
if (!ShiftTerms.Add(core.Current))
{
return;
}
if (core.Current is Terminal)
{
ShiftTerminals.Add(core.Current as Terminal);
}
//If current term (core.Current) is a new non-terminal, expand it
var currNt = core.Current as NonTerminal;
if (currNt == null)
{
return;
}
foreach (var prod in currNt.Productions)
{
AddItem(prod.LR0Items[0]);
}
}//method
public LRItem(ParserState state, LR0Item core)
{
State = state;
Core = core;
_hashCode = unchecked (state.GetHashCode() + core.GetHashCode());
}