编译原理LL1文法分析表算法实现
import hjzgg.first.First; import hjzgg.follow.Follow; import hjzgg.tablenode.TableNode; import hjzgg.treenode.TreeNode; import java.util.ArrayList; import java.util.LinkedHashMap; import java.util.Map; import java.util.Set; import java.util.Stack; import java.util.TreeMap; import java.util.TreeSet; public class AnalysisTable { private final int noFinalCharacterCount = 100; private Map<String, Integer>stringToInt = new TreeMap<String, Integer>();//分析表行 列 字母映射到数字 private Map<Integer, String>tableRow = new TreeMap<Integer, String>();//分析表 行列 数字 映射到字母 private Map<Integer, String>tableCol = new TreeMap<Integer, String>(); private String[][] table = new String[noFinalCharacterCount][];//分析表 private Set<Character>terminalCharacters = new TreeSet<Character>();//终结符集合 private Map<String, Set<Character>> first = null; private Map<String, Set<Character>> follow = null; private Map<String, String[]> mp = null; private int nodeCntRow = 0, nodeCntCol=0; public static final int treeNodeCnt = 200;//树最多节点的个数 private int cntTreeNode = 0; private ArrayList<String> usedProduction = new ArrayList<String>();//预测分析中所用到的产生式 private int fatherNode;//treeGraphic搜素是的开始节点 private TreeNode[] treeGraphic = new TreeNode[treeNodeCnt]; private String[] analysisStack = null; public String[] getAnalysisStack(){ return analysisStack; } public Map<String, Integer> getStringToInt(){ return stringToInt; } public Set<Character> getTerminalCharacters(){ return terminalCharacters; } public int getFatherNode(){ return fatherNode; } public TreeNode[] getTreeGraphic(){ return treeGraphic; } public AnalysisTable(Map<String, Set<Character>> first, Map<String, Set<Character>> follow, Map<String, String[]> mp) { super(); this.first = first; this.follow = follow; this.mp = mp; init(); } private void init(){ for(String leftNode : mp.keySet()){ stringToInt.put(leftNode, ++nodeCntRow); tableRow.put(nodeCntRow, leftNode); String[] rightNodes = mp.get(leftNode); for(int i=0; i<rightNodes.length; ++i){//枚举每一个产生式 for(int j=0; j<rightNodes[i].length(); ++j) if(!mp.containsKey(""+rightNodes[i].charAt(j)) && rightNodes[i].charAt(j)!=‘\‘‘ && rightNodes[i].charAt(j)!=‘$‘){//每一个终结符 if(!stringToInt.containsKey(""+rightNodes[i].charAt(j))){ stringToInt.put(""+rightNodes[i].charAt(j), ++nodeCntCol); terminalCharacters.add(rightNodes[i].charAt(j)); tableCol.put(nodeCntCol, ""+rightNodes[i].charAt(j)); } } } } stringToInt.put("#", ++nodeCntCol); tableCol.put(nodeCntCol, "#"); terminalCharacters.add(‘#‘); } public ArrayList<TableNode> analysisTableKernealCode(){ for(String leftNode : mp.keySet()){ String[] rightNodes = mp.get(leftNode); for(int i=0; i<rightNodes.length; ++i){//枚举每一个产生式 for(Character terminal : terminalCharacters){//每一个终结符 char finalCharacter = terminal; Set<Character> productionFirstSet = new TreeSet<Character>();//产生式对应first集 for(int k=0; k<rightNodes[i].length(); ++k){ String node = ""+rightNodes[i].charAt(k); if(k+1 < rightNodes[i].length() && rightNodes[i].charAt(k+1)==‘\‘‘){ node += ‘\‘‘; ++k; } if(mp.containsKey(node)){//非终结符 productionFirstSet.addAll(first.get(node)); if(!first.get(node).contains(‘$‘)) break; } else {//终结符 productionFirstSet.add(node.charAt(0)); break; } } if(productionFirstSet.contains(finalCharacter)){//A->@ 对于每一个终结符 a属于FIRST(@),加入M[A, a] int col = stringToInt.get(""+finalCharacter); int row = stringToInt.get(leftNode); if(table[row]==null) table[row] = new String[nodeCntCol+1]; table[row][col] = leftNode + "->" + rightNodes[i]; } /***********************************************************************/ else if(productionFirstSet.contains(‘$‘)){//A->@ 对于$属于First(@),对任何b属于Follow(A)则把A->@加入 if(follow.get(leftNode).contains(finalCharacter)){ int col = stringToInt.get(""+finalCharacter); int row = stringToInt.get(leftNode); if(table[row]==null) table[row] = new String[nodeCntCol+1]; table[row][col] = leftNode + "->" + rightNodes[i]; } } } } } return printTalbe(); } public ArrayList<TableNode> printTalbe(){ ArrayList<TableNode> tableNodeAl = new ArrayList<TableNode>(); System.out.println("分析表如下:"); for(int i=1; i<=nodeCntRow; ++i){ for(int j=1; j<=nodeCntCol; ++j) if(table[i]!=null && table[i][j]!=null){ tableNodeAl.add(new TableNode(i, j, table[i][j])); System.out.println(tableRow.get(i) + ":" + tableCol.get(j) + " " + table[i][j]); } } return tableNodeAl; } public boolean predictiveAnalysis(String formula){ ArrayList<String>stringStack = new ArrayList<String>(); System.out.println("开始进行预测分析,分析栈如下:"); Stack<String> stack = new Stack<String>(); stack.push("#"); stack.push(tableRow.get(1)); int formulaIndex = 0; char a = formula.charAt(formulaIndex++); boolean flag = false; while(true){ if(stack.size() == 0){ //error break; } stringStack.add(stack.toString()); System.out.println(stack); String x = stack.pop(); if(!mp.containsKey(x)){//终结符 if(x.charAt(0)==a){ if(a==‘#‘){ flag = true; break; } a = formula.charAt(formulaIndex++); } else { //error } } else {//非终结符 if(table[stringToInt.get(x)] != null){ String production = table[stringToInt.get(x)][stringToInt.get(""+a)]; if(production != null){ usedProduction.add(production); if(!production.contains("$")){//X->X1X2X3....Xk 中 Xk....X3X2X1压入栈中 for(int i=production.length()-1; i>=0; --i){ if(production.charAt(i)==‘>‘) break; if(production.charAt(i)==‘\‘‘){ stack.push(""+production.charAt(i-1)+production.charAt(i)); --i; } else{ stack.push(""+production.charAt(i)); } } } } else { //error } } else { //error } } } analysisStack = stringStack.toArray(new String[stringStack.size()]); return flag; } private int produceAnalysisTree(int curRow, String preNode){ String curProduction = usedProduction.get(curRow); String splits[] = curProduction.split("->"); if(preNode != null && !preNode.equals(splits[0])) return produceAnalysisTree(curRow+1, preNode); TreeNode treeNode = new TreeNode(); treeNode.content = splits[0]; for(int i=0; i<splits[1].length(); ++i){//右部的产生式 String node = "" + splits[1].charAt(i); if(i+1<splits[1].length() && splits[1].charAt(i+1)==‘\‘‘){ node += ‘\‘‘; ++i; } if(!mp.containsKey(node)){//不是 非终结点 TreeNode tmpTreeNode = new TreeNode(); tmpTreeNode.content = node; treeNode.child.add(cntTreeNode);//加入孩子节点 treeGraphic[cntTreeNode++] = tmpTreeNode; } else {//非终结点 int childNodeCnt = produceAnalysisTree(curRow+1, node);//得到这个孩子的节点 treeNode.child.add(childNodeCnt); } } treeGraphic[cntTreeNode] = treeNode; return cntTreeNode++; } private void printAnalysisTree(int curNode){ System.out.print(" " + treeGraphic[curNode].content); for(int i=0; i<treeGraphic[curNode].child.size(); ++i) printAnalysisTree(treeGraphic[curNode].child.get(i)); } public void AnalysisTree(){ fatherNode = produceAnalysisTree(0, null); System.out.println("分析树的先序遍历如下:"); printAnalysisTree(fatherNode); } public static void main(String[] args) { // String[] rightLinearGrammar ={ // "S->iCtSA|a", // "A->$|eS", // "C->b" // }; String[] rightLinearGrammar = { "E->TE\‘", "E\‘->+TE\‘|$", "T->FT\‘", "T\‘->*FT\‘|$", "F->(E)|i" }; // String[] rightLinearGrammar = { // "S->ABc", // "A->a|$", // "B->b|$" // }; Map<String, String[]> mp = new LinkedHashMap<String, String[]>(); try{ for(int i=0; i<rightLinearGrammar.length; ++i){ String split1[] = rightLinearGrammar[i].split("->"); String split2[] = split1[1].split("\\|"); mp.put(split1[0], split2); } } catch(Exception e){ e.printStackTrace(); System.out.println("右线性文法错误!"); } First first = new First(mp); first.firstKernealCode(); Follow follow = new Follow(mp, first.getFirstSet()); follow.followKernealCode(); AnalysisTable analysisTable = new AnalysisTable(first.getFirstSet(), follow.getFollowSet(), mp); analysisTable.analysisTableKernealCode(); analysisTable.predictiveAnalysis("i+i#"); analysisTable.AnalysisTree(); } }
郑重声明:本站内容如果来自互联网及其他传播媒体,其版权均属原媒体及文章作者所有。转载目的在于传递更多信息及用于网络分享,并不代表本站赞同其观点和对其真实性负责,也不构成任何其他建议。