private static string GetUniqueString(HashCache cache) { FOLLOW obj = cache as FOLLOW; return(obj.Dump()); //StringBuilder builder = new StringBuilder(); //builder.Append("FOLLOW("); //builder.Append(obj.Target.Nickname); //builder.Append(") = 【 "); //int count = obj.values.Count; //for (int i = 0; i < count; i++) //{ // builder.Append(obj.values[i].Nickname); // builder.Append(" "); //} //builder.Append("】"); //return builder.ToString(); }
/// <summary> /// 计算文法的FOLLOW集 /// </summary> /// <param name="grammar"></param> /// <param name="nullableDict"></param> /// <param name="firstList4Node"></param> /// <returns></returns> private static void DoGetFollowList( this RegulationList grammar, out FOLLOWCollection followCollection, Dictionary <TreeNodeType, bool> nullableDict, FIRSTCollection firstList4Node) { // 初始化Follow list followCollection = new FOLLOWCollection(); foreach (var item in grammar.GetAllTreeNodeNonLeaveTypes()) { followCollection.TryInsert(new FOLLOW(item)); } // 迭代到不动点 bool changed = false; do { changed = false; foreach (var regulation in grammar) { int count = regulation.RightPart.Count(); for (int index = 0; index < count; index++) { // 准备为target添加follow元素 TreeNodeType target = regulation.RightNode(index); if (target.IsLeave) { continue; } // 叶结点没有follow FOLLOW follow = FindFollow(followCollection, target); // 找到follow对象 for (int checkCount = 0; checkCount < count - (index + 1); checkCount++) { if (Nullable(regulation.RightPart, index + 1, checkCount, nullableDict)) { // nullable之后的FIRST是target的follow的一部分 FIRST first = FindFirst( firstList4Node, regulation.RightNode(index + 1 + checkCount)); foreach (var value in first.Values) { if (value != TreeNodeType.NullNode) { changed = follow.TryInsert(value) || changed; } } } } { // 如果target之后的全部结点都是nullable,说明此regulation.Left的folow也是target的一部分。 if (Nullable(regulation.RightPart, index + 1, count - (index + 1), nullableDict)) { // 找到此regulation.Left的folow FOLLOW refFollow = FindFollow(followCollection, regulation.Left); if (refFollow != follow) { foreach (var item in refFollow.Values) { changed = follow.TryInsert(item) || changed; } } } } } } } while (changed); }
/// <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); } } } } }