public override int Execute(ParsingContext context)
{
Regulation regulation = context.Grammar[RegulationId - 1];
var newNode = new SyntaxTree();
int tokenCount = 0;
int count = regulation.RightPart.Count();
for (int i = 0; i < count; i++)
{
var item = context.TreeStack.Pop();
context.StateIdStack.Pop();//只弹出，不再使用。
newNode.Children.Insert(0, item);
item.Parent = newNode;
tokenCount += item.MappedTokenLength;
if (i == 0)
{
newNode.MappedTokenStartIndex = item.MappedTokenStartIndex;
}
}
newNode.MappedTokenLength = tokenCount;
newNode.MappedTotalTokenList = context.TokenList;
newNode.NodeType = regulation.Left;
context.TreeStack.Push(newNode);
int stateId = context.StateIdStack.Peek();
LRParsingAction gotoAction = context.ParsingMap.GetAction(stateId, regulation.Left);
gotoAction.Execute(context);
return(context.CurrentTokenIndex);
}
private static string getUniqueString(HashCache cache)
{
Regulation obj = cache as Regulation;
return(obj.Dump());
//StringBuilder builder = new StringBuilder();
//builder.Append(obj.Left.Nickname);
//builder.Append(" ::= ");
//builder.Append(obj.RightPart);
//builder.Append(" ;");
//return builder.ToString();
}
/// <summary>
/// LR(0)项：Regulation + 圆点的位置
/// </summary>
/// <param name="regulation"></param>
/// <param name="dotPosition"></param>
public LR0Item(Regulation regulation, int dotPosition)
: base(GetUniqueString)
{
if (regulation == null)
{
throw new ArgumentNullException();
}
if (dotPosition < 0 || regulation.RightPart.Count() < dotPosition)
{
throw new ArgumentOutOfRangeException();
}
this.Regulation = regulation;
this.DotPosition = dotPosition;
}
/// <summary>
/// LR(1)项（A->α.β,x）指出，序列α在栈顶，且输入中开头的是可以从βx导出的符号。
/// </summary>
/// <param name="regulation">A->αβ/param>
/// <param name="dotPosition">圆点的位置</param>
/// <param name="lookAheadNodeType">x代表的类型</param>
public LR1Item(Regulation regulation, int dotPosition, TreeNodeType lookAheadNodeType)
: base(GetUniqueString)
{
if (regulation == null || lookAheadNodeType == null)
{
throw new ArgumentNullException();
}
if (dotPosition < 0 || regulation.RightPart.Count() < dotPosition)
{
throw new ArgumentOutOfRangeException();
}
this.Regulation = regulation;
this.DotPosition = dotPosition;
this.LookAheadNodeType = lookAheadNodeType;
}
/// <summary>
/// 用SLR分析法计算分析表
/// </summary>
/// <param name="grammar"></param>
/// <returns></returns>
public static void GetSLRParsingMap(this RegulationList grammar,
out LRParsingMap map,
out LR0StateCollection stateCollection,
out LR0EdgeCollection edgeCollection, TextWriter writer)
{
// 给文法添加一个辅助的开始产生式 S' -> S $
// 如何添加一个外来的结点类型？用Enum是无法做到的。
var decoratedS = new TreeNodeType("__S2", "S'", "<S'>");
var decoratedEnd = TreeNodeType.endOfTokenListNode;
var decoratedRegulation = new Regulation(
decoratedS, grammar[0].Left, decoratedEnd);
var decoratedGrammar = new RegulationList(decoratedRegulation);
decoratedGrammar.AddRange(grammar);
// 初始化T为{ Closure(S' -> S $) }
var firstItem = new LR0Item(decoratedGrammar[0], 0);
var firstState = new LR0State(firstItem);
firstState = decoratedGrammar.Closure(firstState);
stateCollection = new LR0StateCollection(firstState);
edgeCollection = new LR0EdgeCollection(stateCollection);
var queue = new Queue <LR0State>();
queue.Enqueue(firstState);
int lastOutputLength = 0;
int stateListCount = 1;
int queueCount = 1;
while (queue.Count > 0)
{
LR0State fromState = queue.Dequeue(); queueCount--;
int itemIndex = 0;
int itemCount = fromState.Count();
foreach (var item in fromState)
{
{
TextWriter currentWriter = Console.Out;
if (Console.Out != writer)
{
Console.SetOut(writer);
}
for (int i = 0; i < lastOutputLength; i++)
{
Console.Write('\u0008');
}
string output = string.Format("Calculating SLR State List: {0} <-- {1}, working on {2}/{3} ...",
stateListCount, queueCount, 1 + itemIndex++, itemCount);
Console.Write(output);
lastOutputLength = output.Length;
Console.SetOut(currentWriter);
}
TreeNodeType x = item.GetNodeNext2Dot();
if (x == null || x == decoratedEnd)
{
continue;
}
LR0State toState = decoratedGrammar.Goto(fromState, x);
if (stateCollection.TryInsert(toState))
{
queue.Enqueue(toState);
stateListCount++;
queueCount++;
var edge = new LR0Edge(fromState, x, toState);
edgeCollection.TryInsert(edge);
}
else
{
int index = stateCollection.IndexOf(toState);
toState = stateCollection[index];
var edge = new LR0Edge(fromState, x, toState);
edgeCollection.TryInsert(edge);
}
}
}
{
TextWriter currentWriter = Console.Out;
if (Console.Out != writer)
{
Console.SetOut(writer);
}
Console.WriteLine();
Console.SetOut(currentWriter);
}
map = new LRParsingMap();
foreach (var edge in edgeCollection)
{
if (edge.X.IsLeave)
{
int stateId = edge.From.ParsingMapIndex + 1; //stateCollection.IndexOf(edge.From) + 1
int gotoStateId = edge.To.ParsingMapIndex + 1; //stateCollection.IndexOf(edge.To) + 1
map.SetAction(stateId, edge.X, new LR1ShiftInAction(gotoStateId));
}
else
{
int stateId = edge.From.ParsingMapIndex + 1; //stateCollection.IndexOf(edge.From) + 1
int gotoStateId = edge.To.ParsingMapIndex + 1; //stateCollection.IndexOf(edge.To) + 1
map.SetAction(stateId, edge.X, new LR1GotoAction(gotoStateId));
}
}
var endItem = new LR0Item(decoratedRegulation, 1);
FOLLOWCollection followCollection;
decoratedGrammar.GetFollowCollection(out followCollection);
foreach (var state in stateCollection)
{
if (state.Contains(endItem))
{
int stateId = state.ParsingMapIndex + 1;//stateCollection.IndexOf(state) + 1
map.SetAction(stateId, decoratedEnd, new LR1AceptAction());
}
foreach (var lr0Item in state)
{
if (lr0Item.GetNodeNext2Dot() == null)
{
FOLLOW follow = FindFollow(followCollection, lr0Item.Regulation.Left);
foreach (var value in follow.Values)
{
int stateId = state.ParsingMapIndex + 1;// stateCollection.IndexOf(state) + 1;
int reductionId = decoratedGrammar.IndexOf(lr0Item.Regulation);
var action = new LR1ReducitonAction(reductionId);
map.SetAction(stateId, value, action);
}
}
}
}
}
/// <summary>
/// 用LR(1)分析法计算分析表
/// </summary>
/// <param name="grammar"></param>
/// <returns></returns>
public static void GetLR1ParsingMap(this RegulationList grammar,
out LRParsingMap map,
out LR1StateCollection stateCollection,
out LR1EdgeCollection edgeCollection, TextWriter originalOut)
{
// 给文法添加一个辅助的开始产生式 S' -> S $
// 如何添加一个外来的结点类型？用Enum是无法做到的。
var decoratedS = new TreeNodeType("__S2", "S'", "<S'>");
var decoratedEnd = TreeNodeType.endOfTokenListNode;
var decoratedRegulation = new Regulation(
decoratedS, grammar[0].Left, decoratedEnd);
var decoratedGrammar = new RegulationList(decoratedRegulation);
decoratedGrammar.AddRange(grammar);
// 初始化T为{ Closure(S' -> S $) }
var firstItem = new LR1Item(decoratedGrammar[0], 0, decoratedEnd);
var firstState = new SmallerLR1State(firstItem);
Dictionary <TreeNodeType, bool> nullableDict;
decoratedGrammar.GetNullableDict(out nullableDict);
FIRSTCollection firstCollection;
decoratedGrammar.GetFirstCollection(out firstCollection, nullableDict);
firstState = decoratedGrammar.Closure(firstState, nullableDict, firstCollection);
stateCollection = new LR1StateCollection(firstState);
edgeCollection = new LR1EdgeCollection(stateCollection);
var queue = new Queue <SmallerLR1State>();
queue.Enqueue(firstState);
int lastOutputLength = 0;
int stateListCount = 1;
int queueCount = 1;
while (queue.Count > 0)
{
SmallerLR1State fromState = queue.Dequeue(); queueCount--;
int itemIndex = 0;
int groupCount = fromState.GroupCount;
foreach (var group in fromState.GetGroups())
{
{
TextWriter currentWriter = Console.Out;
if (Console.Out != originalOut)
{
Console.SetOut(originalOut);
}
for (int i = 0; i < lastOutputLength; i++)
{
Console.Write('\u0008');
}
string output = string.Format("Calculating LR(1) State List: {0} <-- {1}, working on group {2}/{3} ...",
stateListCount, queueCount, 1 + itemIndex++, groupCount);
Console.Write(output);
lastOutputLength = output.Length;
Console.SetOut(currentWriter);
}
TreeNodeType x = group.Item1.GetNodeNext2Dot();
if (x == null || x == decoratedEnd)
{
continue;
}
SmallerLR1State toState = decoratedGrammar.Goto(fromState, x, nullableDict, firstCollection);
if (stateCollection.TryInsert(toState))//融入组织之中吧
{
int index = stateCollection.IndexOf(toState);
toState = stateCollection[index];
queue.Enqueue(toState);
stateListCount++;
queueCount++;
var edge = new LR1Edge(fromState, x, toState);
edgeCollection.TryInsert(edge);
}
else
{
int index = stateCollection.IndexOf(toState);
toState = stateCollection[index];
var edge = new LR1Edge(fromState, x, toState);
edgeCollection.TryInsert(edge);
}
}
}
{
TextWriter currentWriter = Console.Out;
if (Console.Out != originalOut)
{
Console.SetOut(originalOut);
}
Console.WriteLine();
Console.SetOut(currentWriter);
}
map = new LRParsingMap();
foreach (var edge in edgeCollection)
{
if (edge.X.IsLeave)
{
int stateId = edge.From.ParsingMapIndex + 1; // stateCollection.IndexOf(edge.From) + 1;
int gotoId = edge.To.ParsingMapIndex + 1; //stateCollection.IndexOf(edge.To) + 1
map.SetAction(stateId, edge.X, new LR1ShiftInAction(gotoId));
}
else
{
int stateId = edge.From.ParsingMapIndex + 1; // stateCollection.IndexOf(edge.From) + 1;
int gotoId = edge.To.ParsingMapIndex + 1; //stateCollection.IndexOf(edge.To) + 1
map.SetAction(stateId, edge.X, new LR1GotoAction(gotoId));
}
}
// TODO: not implemented
var endItem = new LR1Item(decoratedRegulation, 1, decoratedEnd);
foreach (var state in stateCollection)
{
if (state.Contains(endItem))
{
int stateId = state.ParsingMapIndex + 1;// stateCollection.IndexOf(state) + 1;
map.SetAction(stateId, decoratedEnd, new LR1AceptAction());
}
foreach (var LR1Item in state)
{
if (LR1Item.GetNodeNext2Dot() == null)
{
int stateId = state.ParsingMapIndex + 1;// stateCollection.IndexOf(state) + 1;
map.SetAction(stateId, LR1Item.LookAheadNodeType,
new LR1ReducitonAction(decoratedGrammar.IndexOf(LR1Item.Regulation)));
}
}
}
}
