private bool CheckExist(ISet <LR0Item> set, out LR0State targetState)
{
bool exist = false;
targetState = null;
foreach (var state in m_states)
{
if (set.SetEquals(state.ItemSet))
{
exist = true;
targetState = state;
break;
}
}
return(exist);
}
public void BuildModel()
{
ISet<LR0Item> initStateSet = new HashSet<LR0Item>();
initStateSet.Add(new LR0Item(m_infoManager.GetInfo(m_infoManager.RootProduction).Index, 0));
initStateSet = GetClosure(initStateSet);
LR0State initState = new LR0State(initStateSet);
initState.Index = 0;
m_states.Add(initState);
bool isChanged = false;
List<LR0State> changedStates = new List<LR0State>(m_states);
List<LR0State> swapList = new List<LR0State>();
//build shifts and gotos
do
{
isChanged = false;
//swap lists in different usages
var states = changedStates;
changedStates = swapList;
changedStates.Clear();
swapList = states;
Parallel.ForEach(states,
/*
* calculate goto/shift of each item set in parallel
*/
state =>
{
state.PossibleEdges.Clear();
foreach (var item in state.ItemSet)
{
var production = m_infoManager.Productions[item.ProductionIndex];
var info = m_infoManager.GetInfo(production);
//m_dotSymbolVisitor.DotLocation = item.DotLocation;
var symbols = production.Accept(m_dotSymbolVisitor, item.DotLocation);
foreach (var symbol in symbols)
{
if (symbol.IsEos)
{
//accept
state.IsAcceptState = true;
continue;
}
var targetStateSet = GetGoto(state.ItemSet, symbol);
state.PossibleEdges.Add(new KeyValuePair<IProduction, ISet<LR0Item>>(symbol, targetStateSet));
//calculate lexer states that the current LR0 state should cover
if (symbol.IsTerminal && !symbol.IsEos)
{
Terminal t = symbol as Terminal;
Token token = t.Token;
state.AddShiftingLexer(token.LexerIndex);
}
}
}
}
);
foreach (var state in states)
{
foreach (var possibleEdge in state.PossibleEdges)
{
var symbol = possibleEdge.Key;
var targetStateSet = possibleEdge.Value;
LR0State targetState;
//check if the target state is exist
bool exist = CheckExist(targetStateSet, out targetState);
if (exist)
{
//check edges
isChanged = state.AddEdge(symbol, targetState) || isChanged;
}
else
{
isChanged = true;
//create new state
targetState = new LR0State(targetStateSet);
targetState.Index = m_states.Count;
m_states.Add(targetState);
//create edge for it
state.AddEdge(symbol, targetState);
changedStates.Add(targetState);
}
}
}
} while (isChanged);
//build reduces
Parallel.ForEach(m_states,
state =>
{
foreach (var item in state.ItemSet)
{
var production = m_infoManager.Productions[item.ProductionIndex];
var info = m_infoManager.GetInfo(production);
if (item.DotLocation == info.SymbolCount)
{
foreach (var followSymbol in info.Follow)
{
//reduce
state.AddReduce(followSymbol, production);
if (!followSymbol.IsEos)
{
Terminal t = followSymbol as Terminal;
Token token = t.Token;
state.AddReducingLexer(token.LexerIndex);
}
}
}
}
}
);
}
private bool CheckExist(ISet<LR0Item> set, out LR0State targetState)
{
bool exist = false;
targetState = null;
foreach (var state in m_states)
{
if (set.SetEquals(state.ItemSet))
{
exist = true;
targetState = state;
break;
}
}
return exist;
}
public void BuildModel()
{
ISet <LR0Item> initStateSet = new HashSet <LR0Item>();
initStateSet.Add(new LR0Item(m_infoManager.GetInfo(m_infoManager.RootProduction).Index, 0));
initStateSet = GetClosure(initStateSet);
LR0State initState = new LR0State(initStateSet);
initState.Index = 0;
m_states.Add(initState);
bool isChanged = false;
List <LR0State> changedStates = new List <LR0State>(m_states);
List <LR0State> swapList = new List <LR0State>();
//build shifts and gotos
do
{
isChanged = false;
//swap lists in different usages
var states = changedStates;
changedStates = swapList;
changedStates.Clear();
swapList = states;
Parallel.ForEach(states,
/*
* calculate goto/shift of each item set in parallel
*/
state =>
{
state.PossibleEdges.Clear();
foreach (var item in state.ItemSet)
{
var production = m_infoManager.Productions[item.ProductionIndex];
var info = m_infoManager.GetInfo(production);
//m_dotSymbolVisitor.DotLocation = item.DotLocation;
var symbols = production.Accept(m_dotSymbolVisitor, item.DotLocation);
foreach (var symbol in symbols)
{
if (symbol.IsEos)
{
//accept
state.IsAcceptState = true;
continue;
}
var targetStateSet = GetGoto(state.ItemSet, symbol);
state.PossibleEdges.Add(new KeyValuePair <IProduction, ISet <LR0Item> >(symbol, targetStateSet));
//calculate lexer states that the current LR0 state should cover
if (symbol.IsTerminal && !symbol.IsEos)
{
Terminal t = symbol as Terminal;
Token token = t.Token;
state.AddShiftingLexer(token.LexerIndex);
}
}
}
}
);
foreach (var state in states)
{
foreach (var possibleEdge in state.PossibleEdges)
{
var symbol = possibleEdge.Key;
var targetStateSet = possibleEdge.Value;
LR0State targetState;
//check if the target state is exist
bool exist = CheckExist(targetStateSet, out targetState);
if (exist)
{
//check edges
isChanged = state.AddEdge(symbol, targetState) || isChanged;
}
else
{
isChanged = true;
//create new state
targetState = new LR0State(targetStateSet);
targetState.Index = m_states.Count;
m_states.Add(targetState);
//create edge for it
state.AddEdge(symbol, targetState);
changedStates.Add(targetState);
}
}
}
} while (isChanged);
//build reduces
Parallel.ForEach(m_states,
state =>
{
foreach (var item in state.ItemSet)
{
var production = m_infoManager.Productions[item.ProductionIndex];
var info = m_infoManager.GetInfo(production);
if (item.DotLocation == info.SymbolCount)
{
foreach (var followSymbol in info.Follow)
{
//reduce
state.AddReduce(followSymbol, production);
if (!followSymbol.IsEos)
{
Terminal t = followSymbol as Terminal;
Token token = t.Token;
state.AddReducingLexer(token.LexerIndex);
}
}
}
}
}
);
}
internal bool AddEdge(IProduction symbol, LR0State targetState)
{
ProductionBase production = symbol as ProductionBase;
return m_edges.Add(new LR0Edge(Index, production.Info.Index, targetState.Index));
}
internal bool AddEdge(IProduction symbol, LR0State targetState)
{
ProductionBase production = symbol as ProductionBase;
return(m_edges.Add(new LR0Edge(Index, production.Info.Index, targetState.Index)));
}