Add FIRST and FOLLOW functions; syntaxInput.txt Modified;

This commit is contained in:
Saturneric 2021-04-26 02:24:29 +08:00
parent 0c5a118791
commit 5719281600
2 changed files with 367 additions and 372 deletions

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@ -1 +1,8 @@
struct_type->"struct" ID "{" member_list "}" EOF
@E -> T E'
E' -> "+" T E'
E' -> ε
T -> F T'
T' -> "*" F T'
T' -> ε
F -> "(" @E ")"
F -> "id"

708
main.cpp
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@ -1,70 +1,118 @@
#include <iostream>
#include <ctime>
#include <fstream>
#include <utility>
#include <vector>
#include <string>
#include <sstream>
#include <codecvt>
#include <set>
#include <map>
#include <memory>
#include <locale>
using namespace std;
using std::vector;
using std::string;
using std::stringstream;
using std::wstring;
using std::wstringstream;
using std::pair;
using std::shared_ptr;
using std::wcout;
using std::endl;
using std::to_string;
struct Symbol {
const int index;
const string name;
const wstring name;
const bool terminator;
const bool start;
Symbol(int index, string name, bool terminator):
Symbol(int index, wstring name, bool terminator, bool start):
index(index),
name(std::move(name)),
terminator(terminator)
terminator(terminator),
start(start)
{}
};
class SymbolTable {
int index = 0;
map<string, Symbol> table;
int index = 1;
map<wstring, Symbol *> table;
map<int, Symbol *> cache;
vector<const Symbol *> line;
public:
int addSymbol(const string& name, bool terminator) {
const auto &it = table.find(name);
if (it != table.end()) {
return it->second.index;
}
Symbol symbol = Symbol(index++, name, terminator);
table.insert(pair<string, Symbol>(symbol.name, symbol));
return symbol.index;
SymbolTable() {
auto symbol = new Symbol(0, L"ε", true, false);
table.insert(pair<wstring, Symbol *>(L"ε", symbol));
cache.insert(pair<int, Symbol *>(0, symbol));
line.push_back(symbol);
symbol = new Symbol(-1, L"$", true, false);
table.insert(pair<wstring, Symbol *>(L"$", symbol));
cache.insert(pair<int, Symbol *>(-1, symbol));
line.push_back(symbol);
}
int getSymbolIndex(const string &name) {
const vector<const Symbol *> &getAllSymbols() {
return line;
}
int addSymbol(const wstring& name, bool terminator) {
Symbol *symbol = nullptr;
if(name == L"ε") {
return 0;
} else if (name[0] == L'@') {
symbol = new Symbol(index, name, terminator, true);
} else {
symbol = new Symbol(index, name, terminator, false);
}
const auto &it = table.find(name);
if (it != table.end()) {
return it->second->index;
}
table.insert(pair<wstring, Symbol *>(symbol->name, symbol));
cache.insert(pair<int, Symbol *>(symbol->index, symbol));
line.push_back(symbol);
index++;
return symbol->index;
}
const Symbol *getSymbol(int symbol_index) {
const auto &it = cache.find(symbol_index);
if(it != cache.end()) {
return it->second;
} else {
throw runtime_error("symbol " + to_string(symbol_index) + " NOT Found");
}
}
int getSymbolIndex(const wstring &name) {
const auto &it = table.find(name);
if(it != table.end()) {
return it->second.index;
return it->second->index;
} else {
throw runtime_error("symbol " + name + " NOT Found");
throw runtime_error("symbol NOT Found");
}
}
};
// 产生式
class Production {
struct Production {
const int left;
const vector<int> right;
public:
Production(int left, vector<int> right): left(left), right(std::move(right)) {}
};
@ -72,50 +120,34 @@ public:
// 项
class Item{
// 对应的产生式
shared_ptr<Production> production;
Production* production;
// 点的位置
int dotIndex = 0;
public:
explicit Item(shared_ptr<Production> &&p_pdt) {
explicit Item(Production *p_pdt) {
production = p_pdt;
}
};
class Generator{
// 文件输入
wifstream input;
ifstream input("syntaxInput.txt");
// 符号表
SymbolTable symbolTable;
// 产生式
vector<Production *> productions;
map<int, shared_ptr<Production>> productions;//读入文件后,存放产生式
map<string, set<string>> project;//在每个产生式右部前面加上点,得到初始项目集
map<int, set<string>> StateSet;//状态
map<int, set<string>> StateSetTemp;
string css_by_order[20];
string link[12][12];//存放各个状态之间的关系
// FIRST结果存储表
map<int, set<int> *> firsts;
SymbolTable symbolTable;
// FOLLOW结果存储表
map<int, set<int> *> follows;
vector<vector<string>> ActionTable;
vector<vector<int>> GoToTable;
set<string> Vn;
set<string> Vt;
vector<string> vn_index;
vector<string> vt_index;
bool isVn(char ch) {
if (ch >= 'A' && ch <= 'Z') {
return true;
} else{
return false;
}
}
// 去掉首尾空格
string& trim(string &&str) {
// 去掉首尾空格
static wstring& trim(wstring &&str) {
if (str.empty()) {
return str;
}
@ -123,45 +155,282 @@ string& trim(string &&str) {
str.erase(0,str.find_first_not_of(' '));
str.erase(str.find_last_not_of(' ') + 1);
return str;
}
}
//得到最初项目集
void getProject() {
set<int > *FIRST(const vector<int> &symbols, int start_index) {
// 生成集合
auto *non_terminator_symbols = new set<int>();
for(int i = start_index; i < symbols.size(); i++) {
const auto p_non_term_set = FIRST(symbols[i]);
non_terminator_symbols->insert(p_non_term_set->begin(), p_non_term_set->end());
const auto sec_it = p_non_term_set->find(0);
if(sec_it != p_non_term_set->end()) {
continue;
} else {
break;
}
}
return non_terminator_symbols;
}
set<int>* FIRST(int symbol) {
// 查找缓存
const auto it = firsts.find(symbol);
if(it != firsts.end()) {
return it->second;
}
// 生成集合
auto *non_terminator_symbols = new set<int>();
// 如果是终结符
if(symbolTable.getSymbol(symbol)->terminator) {
non_terminator_symbols->insert(symbol);
} else {
bool production_found = false;
// 遍历每一产生式
for (const auto &production : productions) {
Production *p_pdt = production;
if (p_pdt->left != symbol) continue;
production_found = true;
for (const auto &right_symbol : p_pdt->right) {
const auto p_non_term_set = FIRST(right_symbol);
non_terminator_symbols->insert(p_non_term_set->begin(), p_non_term_set->end());
const auto sec_it = p_non_term_set->find(0);
if(sec_it != p_non_term_set->end()) {
continue;
} else {
break;
}
}
}
if (!production_found) non_terminator_symbols->insert(0);
}
this->firsts.insert(pair<int, set<int> *>(symbol, non_terminator_symbols));
return non_terminator_symbols;
}
const set<int> *FOLLOW(int symbol) {
if(follows.empty()) {
FOLLOW();
}
const auto it = follows.find(symbol);
if(it != follows.end()) {
return it->second;
} else {
throw runtime_error("symbol NOT Found");
}
}
void FOLLOW() {
for (const auto &symbol : symbolTable.getAllSymbols()) {
if (!symbol->terminator) {
if (symbol->start) {
set<int> *non_terminator_symbols = get_follow_set(symbol->index);
non_terminator_symbols->insert(-1);
}
}
}
// 指导没有新的符号被添加到任意FOLLOW集合
bool ifAdded = true;
while(ifAdded) {
ifAdded = false;
set<int> *non_terminator_symbols = nullptr;
for (const auto &production : productions) {
const auto &right_symbols = production->right;
set<int> equal_left_non_terminators;
for (int i = 0; i < right_symbols.size() - 1; i++) {
// 非终结符
if (!symbolTable.getSymbol(right_symbols[i])->terminator) {
const auto p_non_term_set = FIRST(right_symbols, i + 1);
// 获得FOLLOW集
non_terminator_symbols = get_follow_set(right_symbols[i]);
const size_t set_size = non_terminator_symbols->size();
non_terminator_symbols->insert(p_non_term_set->begin(), p_non_term_set->end());
// 在集合中发现空字符
if(non_terminator_symbols->find(0) != non_terminator_symbols->end()) {
non_terminator_symbols->erase(0);
equal_left_non_terminators.insert(right_symbols[i]);
}
// 检查是否有新的终结符号被添加
if(set_size < non_terminator_symbols->size()) {
ifAdded = true;
}
}
}
if(!right_symbols.empty()) {
if (!symbolTable.getSymbol(right_symbols[right_symbols.size() - 1])->terminator) {
equal_left_non_terminators.insert(right_symbols[right_symbols.size() - 1]);
}
}
for(const auto symbol : equal_left_non_terminators) {
// 获得左边非终结符的FOLLOW集
const auto left_non_terminator_symbols = get_follow_set(production->left);
// 获得FOLLOW集
non_terminator_symbols = get_follow_set(symbol);
const size_t set_size = non_terminator_symbols->size();
non_terminator_symbols->insert(
left_non_terminator_symbols->begin(),
left_non_terminator_symbols->end());
if(non_terminator_symbols->find(0) != non_terminator_symbols->end()) {
non_terminator_symbols->erase(0);
}
// 检查是否有新的终结符号被添加
if(set_size < non_terminator_symbols->size()) {
ifAdded = true;
}
}
}
}
}
set<int>* get_follow_set(int symbol) {
set<int> *non_terminator_symbols = nullptr;
// 查找缓存
auto it = follows.find(symbol);
if(it != follows.end()) {
non_terminator_symbols = it->second;
} else {
non_terminator_symbols = new set<int>();
this->follows.insert(pair<int, set<int> *>(symbol, non_terminator_symbols));
}
return non_terminator_symbols;
}
void print_symbols(const set<int> &symbols_index) {
wcout << L"{ ";
for(const auto & symbol_index : symbols_index) {
auto *p_sym = symbolTable.getSymbol(symbol_index);
if(p_sym->terminator) {
if (p_sym->name == L"ε") {
wcout << L" [Epsilon] ";
}
else wcout << L" \"" << p_sym->name << L"\" ";
} else {
wcout << L" " << p_sym->name << L" ";
}
}
wcout << L"}" << endl;
}
public:
Generator(): input("syntaxInput.txt", std::ios::binary) {
auto* codeCvtToUTF8= new std::codecvt_utf8<wchar_t>;
input.imbue(std::locale(input.getloc(), codeCvtToUTF8));
}
void test() {
auto p_non_term_set = FIRST(1);
print_symbols(*p_non_term_set);
p_non_term_set = FIRST(3);
print_symbols(*p_non_term_set);
p_non_term_set = FIRST(6);
print_symbols(*p_non_term_set);
FOLLOW();
print_symbols(*FOLLOW(2));
print_symbols(*FOLLOW(6));
print_symbols(*FOLLOW(3));
}
// 得到所有的产生式
void getProductions() {
//读入文法文件
string temp_line;
wstring temp_line;
while (getline(input, temp_line)) {
auto middle_index = temp_line.find("->", 0);
auto middle_index = temp_line.find(L"->", 0);
if(middle_index == string::npos) {
throw runtime_error("-> NOT FOUND");
}
string front = trim(temp_line.substr(0, middle_index));
wstring front = trim(temp_line.substr(0, middle_index));
int left = symbolTable.addSymbol(front, false);
string back = trim(temp_line.substr(middle_index + 2, temp_line.size() - middle_index - 2));
wstring back = trim(temp_line.substr(middle_index + 2, temp_line.size() - middle_index - 2));
stringstream terminator, non_terminator;
wstringstream terminator, non_terminator;
vector<int> symbols;
bool is_terminator = false;
for(const auto &c : back) {
if (c == '\"') {
if (c == L'\"') {
if(is_terminator) {
symbols.push_back(symbolTable.addSymbol(trim(terminator.str()), true));
terminator.str("");
terminator.str(L"");
terminator.clear();
}
is_terminator = !is_terminator;
continue;
}
if(c == ' ') {
string temp_symbol = trim(non_terminator.str());
if(c == L' ' || c == L'\r') {
wstring temp_symbol = trim(non_terminator.str());
if(!temp_symbol.empty()) {
symbols.push_back(symbolTable.addSymbol(trim(non_terminator.str()), false));
non_terminator.str("");
non_terminator.str(L"");
non_terminator.clear();
}
continue;
@ -173,309 +442,28 @@ void getProject() {
}
}
auto p_pdt = make_shared<Production>(left, symbols);
auto p_pdt = new Production(left, symbols);
productions[left] = p_pdt;
}
productions.push_back(p_pdt);
//构造基本项目集,即圆点位于右部开头的位置
string dot = "*";
for(const auto &item : productions) {
for(set<string>::iterator ij =it->second.begin(); ij != it->second.end(); ij++) {
string startStr = *ij;
startStr.insert(0, dot, 0, 1);
project[it->first].insert(startStr);
}
}
}
void Init_I0() {
StateSet[0].insert("S'->*S");
//先将所有的左部为S的产生式加入0号状态中
for(map<string, set<string> >::iterator it = project.begin(); it != project.end(); it++) {
if ((it->first) == "S") {
for(set<string>::iterator ij = it->second.begin(); ij != it->second.end(); ij++) {
StateSetTemp[0].insert(it->first + "->" + *ij);
}
}
}
//根据I0状态中已知内容添加后续
while (! StateSetTemp[0].empty()){
set<string>::iterator it = StateSetTemp[0].begin();
string it_str = *it;//暂时集合中的每一条产生式
//如果点后面是非终结符在project例找到它能推出来的产生式加入temp,
if (isVn(it_str[4])) {
string after_dot_ch = it_str.substr(4,1);
for(set<string>::iterator css = project[after_dot_ch].begin(); css != project[after_dot_ch].end(); css++) {
StateSetTemp[0].insert(after_dot_ch + "->" + *css);
}
StateSetTemp[0].erase(it_str);
StateSet[0].insert(it_str);
}else if(! isVn(it_str[4])) {
StateSetTemp[0].erase(it_str);
StateSet[0].insert(it_str);
}
}
}
string MoveDot(string s, int pos) {
s.erase(pos,1);
s = s.substr(0, pos+1) + "*" + s.substr(pos+1, s.length()-pos);
return s;
}
void GenerateState() {
Init_I0();
int i = 0;
int state_num = 0;
string enter;
//对于每一个状态
while (i < StateSet.size()) {
map<string, set<string>> after_dot_ch;
//构造该状态中的after_dot_ch的mapfirst为点后面的字母即输入字母second为输入字母为first时的项目
for (set<string>::iterator it = StateSet[i].begin(); it != StateSet[i].end(); it++) {//对于此状态的每一个项目
int dot_pos = (*it).find("*");
if (dot_pos + 1 != (*it).length()) {
string s = (*it).substr(dot_pos + 1, 1);//点后面的字母
after_dot_ch[s].insert(*it);
}
}
if (after_dot_ch.size() == 0) {
i++;
continue;
}
for (map<string, set<string>>::iterator adc = after_dot_ch.begin(); adc != after_dot_ch.end(); adc++) {
enter = adc->first;
state_num++;
for (set<string>::iterator p = adc->second.begin(); p != adc->second.end(); p++) {
int dot_pos = (*p).find("*");
string moved_proj = MoveDot(*p, dot_pos);
int moved_dot_pos = (moved_proj).find("*");
StateSet[state_num].insert(moved_proj);
string moved_adc = moved_proj.substr(moved_dot_pos + 1, 1);
if (isVn(moved_adc[0])) {
//如果点移动后的字符串中点后字母是非终结符则将以该非终结符开头的project加入该状态
for (set<string>::iterator proj_css = project[moved_adc].begin();
proj_css != project[moved_adc].end(); proj_css++) {
StateSet[state_num].insert(moved_adc + "->" + (*proj_css));
}
}
}
//--------判断之前是否有与新产生的状态相等的--------
bool is_equal = false;
for (int j = 0; j < state_num; ++j) {
if (StateSet[state_num].size() == StateSet[j].size()) {
for (set<string>::iterator str = StateSet[j].begin(); str != StateSet[j].end(); str++) {
if (StateSet[state_num].count(*str) == 0){
break;
} else{
link[i][j] = enter;
is_equal = true;
}
}
}
}
if (is_equal == true) {//两个状态全部项目都相等
StateSet.erase(state_num);
state_num--;
} else{
link[i][state_num] = enter;
}
//--------------------------------------------
}
i++;
}
}
void printState() {
cout << "-------------------------Status--------------------------"<<endl;
for(map<int, set<string>>::iterator it = StateSet.begin(); it != StateSet.end(); it++) {
cout << "I_" << it->first << ": ";
for(set<string>::iterator ij = it->second.begin(); ij != it->second.end(); ij++) {
cout << *ij << ", ";
}
cout << endl;
}
cout << "---------------------------------------------------------"<<endl;
}
void printLinkedTable() {
cout << "============================================DFA================================================"<<endl;
cout << '\t';
for (int i = 0; i < 11; ++i) {
cout << i << '\t';
}
cout << endl;
for (int i = 0; i < 11; ++i) {
cout << i << '\t';
for (int j = 0; j < 11; ++j) {
cout << link[i][j] << '\t';
}
cout << endl;
}
}
void getVnandVt() {
for(map<string, set<string>>::iterator it = productions.begin(); it != productions.end(); it++) {
string c = it->first;
if (c != "S'")
Vn.insert(c);
for(set<string>::iterator ij = it->second.begin(); ij != it->second.end(); ij++) {
for (int i = 0; i < (*ij).length(); ++i) {
if (!isVn((*ij)[i])) {
Vt.insert((*ij).substr(i, 1));
}
}
}
}
Vt.insert("#");
}
int findIndex(string enter) {
int pos;
if (!isVn(enter[0])) {
for (int k = 0; k < 10; ++k) {
if (vt_index[k] == enter) {
pos = k;
break;
}
}
} else{
for (int k = 0; k < 10; ++k) {
if (vn_index[k] == enter) {
pos = k;
break;
}
}
}
return pos;
}
void GenerateAction_Table() {
//构造Action分析表的行名与列名
ActionTable[0][0] = "";
int j = 0;
set<string>::iterator ij = Vt.begin();
while (j < Vt.size()) {
vt_index[j] = *ij;
ij++; j++;
}
//构造Action表
// ---------移入
for (int i = 0; i < StateSet.size(); ++i) {
for (int j = 0; j < StateSet.size(); ++j) {
if (link[i][j].length() != 0 && (!isVn(link[i][j][0]))) {
string enter = link[i][j];
int pos = findIndex(enter);
ActionTable[i][pos] = "s" + to_string(j);
}
}
}
// ---------规约
for (int l = 0; l < StateSet.size(); ++l) {
if (StateSet[l].size() == 1) {
set<string>::iterator it = StateSet[l].begin();
string proj = *it;
if (proj == "S'->S*") {
ActionTable[l][findIndex("#")] = "acc";
continue;
}
int dot_pos = proj.find("*");
if (dot_pos+1 == proj.length()) {
string no_dot_proj = proj.erase(dot_pos,1);
//先找到这个项目对应的无点产生式index
int index = 0;//无点产生式的编号index。第几条产生式
for (index = 0; index < 20; ++index) {
if (css_by_order[index] == no_dot_proj) {
break;
}
}
for (int m = 0; m < Vt.size(); ++m) {
ActionTable[l][m] = "r" + to_string(index);
}
}
}
}
cout << endl;
cout << endl;
cout << "----------------------[Action]---------------------" << endl;
int m = 0;
cout << '\t';
while (vt_index[m].length() != 0) {
cout << vt_index[m] << '\t';
m++;
}
cout << endl;
for (int k = 0; k < StateSet.size(); ++k) {
cout << k << '\t';
for (int l = 0; l < Vt.size(); ++l) {
cout << ActionTable[k][l] << '\t';
}
cout <<endl;
}
}
void GenerateGoTo_Table() {
for(const auto& item : Vn) {
vn_index.push_back(item);
}
// 初始化GOTO表
for(int i = 0; i < StateSet.size(); i++) {
GoToTable.emplace_back();
for(int j = 0; i < StateSet.size(); j++){
GoToTable[i].emplace_back();
}
}
//构造GoTo表
//在link表中遍历
for (int i = 0; i < StateSet.size(); ++i) {
for (int j = 0; j < StateSet.size(); ++j) {
if ( link[i][j].length() != 0 && isVn(link[i][j][0]) ) {
string enter = link[i][j];
int pos = findIndex(enter);
GoToTable[i][pos] = j;
}
}
}
cout << endl;
cout << endl;
cout << "----------------------[GoTo]---------------------" << endl;
int m = 0;
cout << '\t';
while (vn_index[m].length() != 0) {
cout << vn_index[m] << '\t';
m++;
}
cout << endl;
for (int k = 0; k < StateSet.size(); ++k) {
cout << k << '\t';
for (int l = 0; l < Vn.size(); ++l) {
if (GoToTable[k][l] != 0)
cout << GoToTable[k][l] << '\t';
else
cout << '\t';
}
cout << endl;
}
}
};
int main() {
clock_t start,end;//定义clock_t变量
start = clock(); //开始时间
getProject();
// GenerateState();
// printState();
// printLinkedTable();
// getVnandVt();
// GenerateAction_Table();
// GenerateGoTo_Table();
Generator generator;
generator.getProductions();
generator.test();
//输出时间
end = clock(); //结束时间
cout << endl;