Examples with NGA priv.bajdcc.LALR1.syntax.automata.nga.NGA used on opensource projects

Example 1 with NGA

use of priv.bajdcc.LALR1.syntax.automata.nga.NGA in project jMiniLang by bajdcc.

the class NPA method generateNPA.

/**
 * 产生下推自动机
 */
private void generateNPA() {
    /* 下推自动机状态 */
    ArrayList<NPAStatus> NPAStatusList = new ArrayList<>();
    /* 文法自动机状态 */
    ArrayList<NGAStatus> NGAStatusList = new ArrayList<>();
    /* 下推自动机边（规则映射到NGA边） */
    HashMap<Rule, ArrayList<NGAEdge>> ruleEdgeMap = new HashMap<>();
    /* 遍历每条规则 */
    for (Entry<RuleItem, NGAStatus> entry : mapNGA.entrySet()) {
        RuleItem key = entry.getKey();
        NGAStatus value = entry.getValue();
        /* 保存规则 */
        arrRuleItems.add(key);
        /* 搜索当前规则中的所有状态 */
        ArrayList<NGAStatus> CurrentNGAStatusList = getNGAStatusClosure(new BreadthFirstSearch<>(), value);
        /* 搜索所有的边 */
        for (NGAStatus status : CurrentNGAStatusList) {
            /* 若边为非终结符边，则加入邻接表，终结符->带终结符的所有边 */
            status.outEdges.stream().filter(edge -> edge.data.kAction == NGAEdgeType.RULE).forEach(edge -> {
                Rule rule = edge.data.rule.rule;
                if (!ruleEdgeMap.containsKey(rule)) {
                    ruleEdgeMap.put(rule, new ArrayList<>());
                }
                ruleEdgeMap.get(rule).add(edge);
            });
        }
        /* 为所有的NGA状态构造对应的NPA状态，为一一对应 */
        for (NGAStatus status : CurrentNGAStatusList) {
            /* 保存NGA状态 */
            NGAStatusList.add(status);
            /* 新建NPA状态 */
            NPAStatus NPAStatus = new NPAStatus();
            NPAStatus.data.label = status.data.label;
            NPAStatus.data.iRuleItem = arrRuleItems.indexOf(key);
            NPAStatusList.add(NPAStatus);
        }
    }
    /* 遍历所有NPA状态 */
    for (int i = 0; i < NPAStatusList.size(); i++) {
        /* 获得NGA状态 */
        NGAStatus ngaStatus = NGAStatusList.get(i);
        /* 获得NPA状态 */
        NPAStatus npaStatus = NPAStatusList.get(i);
        /* 获得规则 */
        RuleItem ruleItem = arrRuleItems.get(npaStatus.data.iRuleItem);
        /* 检查是否为纯左递归，类似[A::=Aa]此类，无法直接添加纯左递归边，需要LA及归约 */
        if (!isLeftRecursiveStatus(ngaStatus, ruleItem.parent)) {
            /* 当前状态是否为初始状态且推导规则是否属于起始规则（无NGA入边） */
            boolean isInitRuleStatus = initRule == ruleItem.parent;
            /* 若是，则将当前状态对应的NPA状态加入初始状态表中 */
            if (ngaStatus.inEdges.isEmpty() && isInitRuleStatus) {
                arrInitStatusList.add(npaStatus);
            }
            /* 建立计算优先级使用的记号表，其中元素为从当前状态出发的Rule或Token边的First集（LA预查优先） */
            HashSet<Integer> tokenSet = new HashSet<>();
            /* 遍历文法自动机的所有边 */
            for (NGAEdge edge : ngaStatus.outEdges) {
                switch(edge.data.kAction) {
                    case EPSILON:
                        break;
                    case RULE:
                        /* 判断边是否为纯左递归 */
                        if (!isLeftRecursiveEdge(edge, ruleItem.parent)) {
                            for (RuleItem item : edge.data.rule.rule.arrRules) {
                                /* 起始状态 */
                                NGAStatus initItemStatus = mapNGA.get(item);
                                /* 判断状态是否为纯左递归 */
                                if (!isLeftRecursiveStatus(initItemStatus, item.parent)) {
                                    /* 添加Shift边，功能为将一条状态序号放入堆栈顶 */
                                    NPAEdge npaEdge = connect(npaStatus, NPAStatusList.get(NGAStatusList.indexOf(initItemStatus)));
                                    npaEdge.data.handler = edge.data.handler;
                                    npaEdge.data.action = edge.data.action;
                                    npaEdge.data.kAction = NPAEdgeType.SHIFT;
                                    npaEdge.data.inst = NPAInstruction.SHIFT;
                                    npaEdge.data.errorJump = NPAStatusList.get(NGAStatusList.indexOf(edge.end));
                                    /* 为移进项目构造LookAhead表，LA不吃字符，只是单纯压入新的状态（用于规约） */
                                    npaEdge.data.arrLookAhead = new HashSet<>();
                                    npaEdge.data.arrLookAhead.addAll(item.setFirstSetTokens.stream().filter(exp -> !tokenSet.contains(exp.id)).map(exp -> exp.id).collect(Collectors.toList()));
                                }
                            }
                            // 将当前非终结符的所有终结符First集加入tokenSet，以便非终结符的Move的LA操作（优先级）
                            tokenSet.addAll(edge.data.rule.rule.arrTokens.stream().map(exp -> exp.id).collect(Collectors.toList()));
                        }
                        break;
                    case TOKEN:
                        /* 添加Move边，功能为吃掉（匹配）一个终结符，若终结符不匹配，则报错（即不符合文法） */
                        NPAEdge npaEdge = connect(npaStatus, NPAStatusList.get(NGAStatusList.indexOf(edge.end)));
                        npaEdge.data.handler = edge.data.handler;
                        npaEdge.data.action = edge.data.action;
                        npaEdge.data.kAction = NPAEdgeType.MOVE;
                        npaEdge.data.iToken = edge.data.token.id;
                        npaEdge.data.iHandler = arrActions.indexOf(edge.data.action);
                        npaEdge.data.errorJump = npaEdge.end;
                        /* 根据StorageID配置指令 */
                        if (edge.data.iStorage != -1) {
                            npaEdge.data.inst = NPAInstruction.READ;
                            // 参数
                            npaEdge.data.iIndex = edge.data.iStorage;
                        } else {
                            npaEdge.data.inst = NPAInstruction.PASS;
                        }
                        /* 修改TokenSet */
                        if (tokenSet.contains(edge.data.token.id)) {
                            /* 使用LookAhead表 */
                            npaEdge.data.arrLookAhead = new HashSet<>();
                        } else {
                            tokenSet.add(edge.data.token.id);
                        }
                        break;
                    default:
                        break;
                }
            }
            /* 如果当前NGA状态是结束状态（此时要进行规约），则检查是否需要添加其他边 */
            if (ngaStatus.data.bFinal) {
                if (ruleEdgeMap.containsKey(ruleItem.parent)) {
                    /* 遍历文法自动机中附带了当前推导规则所属规则的边 */
                    ArrayList<NGAEdge> ruleEdges = ruleEdgeMap.get(// 当前规约的文法的非终结符为A，获得包含A的所有边
                    ruleItem.parent);
                    for (NGAEdge ngaEdge : ruleEdges) {
                        /* 判断纯左递归，冗长的表达式是为了获得当前边的所在推导式的起始非终结符 */
                        if (isLeftRecursiveEdge(ngaEdge, arrRuleItems.get(NPAStatusList.get(NGAStatusList.indexOf(ngaEdge.begin)).data.iRuleItem).parent)) {
                            /* 添加Left Recursion边（特殊的Reduce边） */
                            NPAEdge npaEdge = connect(npaStatus, NPAStatusList.get(NGAStatusList.indexOf(ngaEdge.end)));
                            npaEdge.data.kAction = NPAEdgeType.LEFT_RECURSION;
                            if (ngaEdge.data.iStorage != -1) {
                                npaEdge.data.inst = NPAInstruction.LEFT_RECURSION;
                                npaEdge.data.iIndex = ngaEdge.data.iStorage;
                            } else {
                                npaEdge.data.inst = NPAInstruction.LEFT_RECURSION_DISCARD;
                            }
                            // 规约的规则
                            npaEdge.data.iHandler = npaStatus.data.iRuleItem;
                            /* 为左递归构造Lookahead表（Follow集），若LA成功则进入左递归 */
                            npaEdge.data.arrLookAhead = new HashSet<>();
                            for (NGAEdge edge : ngaEdge.end.outEdges) {
                                /* 若出边为终结符，则直接加入（终结符First集仍是本身） */
                                if (edge.data.kAction == NGAEdgeType.TOKEN) {
                                    npaEdge.data.arrLookAhead.add(edge.data.token.id);
                                } else {
                                    /* 若出边为非终结符，则加入非终结符的First集 */
                                    npaEdge.data.arrLookAhead.addAll(edge.data.rule.rule.arrTokens.stream().map(exp -> exp.id).collect(Collectors.toList()));
                                }
                            }
                        } else {
                            /* 添加Reduce边 */
                            NPAEdge npaEdge = connect(npaStatus, NPAStatusList.get(NGAStatusList.indexOf(ngaEdge.end)));
                            npaEdge.data.kAction = NPAEdgeType.REDUCE;
                            npaEdge.data.status = NPAStatusList.get(NGAStatusList.indexOf(ngaEdge.begin));
                            if (ngaEdge.data.iStorage != -1) {
                                npaEdge.data.inst = NPAInstruction.TRANSLATE;
                                npaEdge.data.iIndex = ngaEdge.data.iStorage;
                            } else {
                                npaEdge.data.inst = NPAInstruction.TRANSLATE_DISCARD;
                            }
                            // 规约的规则
                            npaEdge.data.iHandler = npaStatus.data.iRuleItem;
                        }
                    }
                }
                if (isInitRuleStatus) {
                    /* 添加Finish边 */
                    NPAEdge npaEdge = connect(npaStatus, npaStatus);
                    npaEdge.data.kAction = NPAEdgeType.FINISH;
                    npaEdge.data.inst = NPAInstruction.TRANSLATE_FINISH;
                    npaEdge.data.iHandler = npaStatus.data.iRuleItem;
                }
            }
        }
    }
}

Example 2 with NGA

use of priv.bajdcc.LALR1.syntax.automata.nga.NGA in project jMiniLang by bajdcc.

the class NGA method generateNGAMap.

/**
 * 产生NGA映射表
 */
private void generateNGAMap() {
    int j = 0;
    for (RuleExp exp : arrNonTerminals) {
        j++;
        int i = 0;
        j = j + i - i;
        for (RuleItem item : exp.rule.arrRules) {
            /* 表达式转换成NGA */
            bag = new NGABag();
            bag.expression = item.expression;
            bag.prefix = exp.name + "[" + i + "]";
            bag.expression.visit(this);
            ENGA enga = bag.nga;
            /* NGA去Epsilon边 */
            NGAStatus status = deleteEpsilon(enga);
            /* 保存 */
            mapNGA.put(item, status);
            i++;
        }
    }
}

Example 3 with NGA

use of priv.bajdcc.LALR1.syntax.automata.nga.NGA in project jMiniLang by bajdcc.

the class NGA method getNGAString.

/**
 * 非确定性文法自动机描述
 *
 * @param status
 *            NGA状态
 * @param prefix
 *            前缀
 * @return 描述
 */
public String getNGAString(NGAStatus status, String prefix) {
    NGAToString alg = new NGAToString(prefix);
    status.visit(alg);
    return alg.toString();
}