代码C++部分是我Liu Yudi写的，Python是室友Qu Ao和Che Pengyuan写的。 下面是PL/0语言的描述：
PL/0语言的BNF描述（扩充的巴克斯范式表示法） <prog> → program <id>；<block> <block> → [<condecl>][<vardecl>][<proc>]<body> <condecl> → const <const>{,<const>}; <const> → <id>:=<integer> <vardecl> → var <id>{,<id>}; <proc> → procedure <id>（[<id>{,<id>]}）;<block>{;<proc>} <body> → begin <statement>{;<statement>}end <statement> → <id> := <exp> |if <lexp> then <statement>[else <statement>] |while <lexp> do <statement> |call <id>（[<exp>{,<exp>}]） |<body> |read (<id>{，<id>}) |write (<exp>{,<exp>}) <lexp> → <exp> <lop> <exp>|odd <exp> <exp> → [+|-]<term>{<aop><term>} <term> → <factor>{<mop><factor>} <factor>→<id>|<integer>|(<exp>) <lop> → =|<>|<|<=|>|>= <aop> → +|- <mop> → *|/ <id> → l{l|d} （注：l表示字母） <integer> → d{d} 注释： <prog>：程序 ；<block>：块、程序体 ；<condecl>：常量说明 ；<const>：常量； <vardecl>：变量说明 ；<proc>：分程序 ； <body>：复合语句 ；<statement>：语句； <exp>：表达式 ；<lexp>：条件 ；<term>：项 ； <factor>：因子 ；<aop>：加法运算符； <mop>：乘法运算符； <lop>：关系运算符 odd：判断表达式的奇偶性。先来词法分析： 1．使用循环分支方法实现PL/0语言的词法分析器，该词法分析器能够读入使用PL/0语言书写的源程序，输出单词符号串及其属性到一中间文件中，具有一定的错误处理能力，给出词法错误提示（需要输出错误所在的行列）。
C++
#include <iostream> #include <fstream> #include <string> #include <cctype> #include <cstring> #include <stdio.h> #include <stdlib.h> using namespace std; string a_line; string reserve[36]={"program","function","procedure","array","const",\ "file","label","of","packed","record","set","type",\ "var","case","do","downto","else","for","forward",\ "goto","if","repeat","then","to","until","while",\ "with","and","div","in","mod","not","or","begin",\ "end","nil"}; bool isreserve(string s); int main(void) { fstream infile,outfile; infile.open("source.txt",ios::in); outfile.open("answer.txt",ios::out); if(outfile.fail()||infile.fail()) { cout<<"error"<<endl; exit(0); } int row = 1; //row代表行数 while(getline(infile,a_line,'\n')) //每次读取一行 { int column=0; //column代表这一行的第几列个字符 string temp; while(column<a_line.size()) { if(isalpha(a_line[column])) { int i=1; temp+=a_line[column]; while(isalpha(a_line[column+1])||isdigit(a_line[column+1])) { temp+=a_line[column+1]; column++; i++; } if(isreserve(temp)) { //cout<<temp<<endl; outfile<<"<"<<temp<<" , reserve"<<">"<<endl; } else outfile<<"<"<<temp<<" , symbol"<<">"<<endl; temp.erase(); } else if(isdigit(a_line[column])) { int i=1; temp+=a_line[column]; bool flag=0; while(isalpha(a_line[column+1])||isdigit(a_line[column+1])) { temp+=a_line[column+1]; if(isalpha(temp[i])) flag=1; column++; i++; } if(flag==0) outfile<<"<"<<temp<<" , number"<<">"<<endl; else //说明出现数字打头的保留字 cout<<"row: "<<row<<" column: "<<column<<" is error!"<<endl; temp.erase(); } else if(a_line[column]=='+'||a_line[column]=='-'||a_line[column]=='*'||a_line[column]=='/'||a_line[column]=='=') outfile<<"<"<<a_line[column]<<" , operator"<<">"<<endl; else if((a_line[column]=='/'&&a_line[column+1]=='*')||(a_line[column]=='*'&&a_line[column+1]=='/')) outfile<<"<"<<a_line[column]<<a_line[column+1]<<" , bound symbol"<<">"<<endl; else if(a_line[column]==';'||a_line[column]=='('||a_line[column]==')'||a_line[column]==',') outfile<<"<"<<a_line[column]<<" , bound symbol"<<">"<<endl; else if(a_line[column]==':') { if(a_line[column+1]=='=') { outfile<<"<"<<a_line[column]<<a_line[column+1]<<" , operator"<<">"<<endl; column++; } else cout<<"row: "<<row<<" column: "<<column<<" is error!"<<endl; } else if(a_line[column]=='<') { if(a_line[column+1]=='='||a_line[column+1]=='>') { outfile<<"<"<<a_line[column]<<a_line[column+1]<<" , operator"<<">"<<endl; column++; } else outfile<<"<"<<a_line[column]<<" , operator"<<">"<<endl; } else if(a_line[column]=='>') { if(a_line[column+1]=='=') { outfile<<"<"<<a_line[column]<<a_line[column+1]<<" , operator"<<">"<<endl; column++; } else outfile<<"<"<<a_line[column]<<" , operator"<<">"<<endl; } column++; } row++; } outfile.close(); infile.close(); return 0; } bool isreserve(string s) { for(int i = 0;i<36;i++) if(s.compare(reserve[i]) == 0) { return true; } return false; }Python
# -*- coding: utf-8 -*- """ Created on Sun Sep 27 18:19:51 2020 @author: chepengyuan """ #定义保留字 RESERVED_WORD= ['write','read','program','function','procedure','array','const','file','label','of','packed','record','set','type','var','case','do','downto','else','for','forward','goto','if','repeat','then','to','until','call','while','with','and','div','in','mod','not','or','begin','end','nil'] #判断保留字，如果是保留字则返回保留字,否则返回False def Is_Key(key): if key in RESERVED_WORD: return key else: return False def List_to_Str(l): l = str(l) #删除无用的字符,[ ] ' l = l.replace("'",'') l = l.replace("[",'') l = l.replace("]",'') l = l.replace(",",'') l = l.replace(' ','') return l CL = []#符号表 #读入源程序 fp = open('3.txt','r',encoding = 'utf-8') #缓冲区 buffer = fp.read() print('缓冲区buffer:',buffer) #替换换行符 buffer = buffer.strip() #行指针 line = 1 c = [] #获取一个字符 i = 0#字符指针 while i <len(buffer): #跳过空格和换行符 while(buffer[i]==' '): print('空格',buffer[i]) i = i + 1 ''' while(True): if buffer[i] =='\n': i = i + 1 line = line + 1 print(line) else: break ''' #读入单词首字符 c.append(buffer[i]) #如果是字母，则继续读取字符串，判断是保留字还是普通符号 if c[-1].isalpha(): #读入一个字符 i = i+1 if i<=len(buffer)-1: c.append(buffer[i]) while(c[-1].isalpha() or c[-1].isdigit()): #判断是否为字符或数字,如果是，则继续读入 if i<len(buffer) -1: i = i + 1 c.append(buffer[i]) else: break #如果不是，则退回一个字符 if i <len(buffer)-1: i = i -1 print('退回：',c[-1]) del (c[-1]) #将当前已经读入的字符列表转换为字符串 c = List_to_Str(c) #判断获取的字符是否为保留字，如果是，则返回保留字 if (Is_Key(c)): print('保留字:',c) token = {'value':List_to_Str(c),'attribute':'reserved_word','line_num':line} CL.append(token) c=list(c) c.clear() #如果不是，则插入符号表，返回标志符类型及在符号表中的指针 else: print('变量',c) token = {'value':List_to_Str(c),'attribute':'identifier','line_num':line} CL.append(token) #Insert_Character_Table(c) #清空当前字符串 c=list(c) c.clear() #如果是数字则继续读入直到读完所有数字 elif(c[-1].isdigit()): i = i + 1 c.append(buffer[i]) while(c[-1].isdigit()): i = i + 1 c.append(buffer[i]) #退回一个字符 i = i -1 del(c[-1]) #插入常数表，返回整型数据类型及在常数表中的指针 #Insert_Const_Table(c) c = List_to_Str(c) print('整型数据类型','常数表中的指针',c) token = {'value':List_to_Str(c),'attribute':'number','line_num':line} CL.append(token) c=list(c) c.clear() #如果是运算符，则返回 elif c[-1] =='(': print('符号：',c[-1]) token = {'value':List_to_Str(c),'attribute':'界符','line_num':line} CL.append(token) del(c[-1]) elif c[-1] ==')': print('符号：',c[-1]) token = {'value':List_to_Str(c),'attribute':'界符','line_num':line} CL.append(token) del(c[-1]) elif c[-1] ==';': print('符号：',c[-1]) token = {'value':List_to_Str(c),'attribute':'界符','line_num':line} CL.append(token) del(c[-1]) elif c[-1] =='=': print('符号：',c[-1]) token = {'value':List_to_Str(c),'attribute':'界符','line_num':line} CL.append(token) del(c[-1]) elif c[-1] ==',': print('符号：',c[-1]) token = {'value':c[-1],'attribute':'界符','line_num':line} CL.append(token) del(c[-1]) elif c[-1] =='+': print('符号：',c[-1]) token = {'value':List_to_Str(c),'attribute':'界符','line_num':line} CL.append(token) del(c[-1]) elif c[-1] =='/': print('符号：',c[-1]) token = {'value':List_to_Str(c),'attribute':'界符','line_num':line} CL.append(token) del(c[-1]) elif c[-1] ==':': #读入一个字符 i = i + 1 c.append(buffer[i]) #判断是否为=,如果是则返回:= if(c[-1] == '='): print('符号：',c[-2],c[-1]) token = {'value':List_to_Str(c),'attribute':'界符','line_num':line} CL.append(token) del (c[-2],c[-1]) #如果不是，则退回一个字符，返回* else: i = i-1 del (c[-1]) print('符号：',c[-1]) token = {'value':List_to_Str(c),'attribute':'界符','line_num':line} CL.append(token) del(c[-1]) elif c[-1] =='*': #读入一个字符 i = i + 1 c.append(buffer[i]) #判断是否为*,如果是则返回** if(c[-1] == '*'): print('符号：',c[-2],c[-1]) token = {'value':List_to_Str(c),'attribute':'界符','line_num':line} CL.append(token) del c[-1],c[-2] #如果不是，则退回一个字符，返回* else: i = i-1 del (c[-1]) print('符号：',c[-1]) token = {'value':List_to_Str(c),'attribute':'界符','line_num':line} CL.append(token) del(c[-1]) elif c[-1] =='<': #读入一个字符 i = i + 1 c.append(buffer[i]) #判断是否为>，如果是则返回<> if(c[-1]=='>'): print('符号：',c[-2],c[-1]) token = {'value':List_to_Str(c),'attribute':'界符','line_num':line} CL.append(token) del c[-2],c[-1] #判断是否为=,如果是则返回<= elif(c[-1] == '='): print('符号：',c[-2],c[-1]) token = {'value':List_to_Str(c),'attribute':'界符','line_num':line} CL.append(token) del(c[-2],c[-1]) #如果不是>,=，则退回一个字符，返回< else: i = i -1 del(c[-1]) print('符号：',c[-1]) token = {'value':List_to_Str(c),'attribute':'界符','line_num':line} CL.append(token) del(c[-1]) elif c[-1] =='>': #读入一个字符 i = i + 1 c.append(buffer[i]) #判断是否为=,如果是则返回>= if(c[-1] =='='): print('符号：',c[-2],c[-1]) token = {'value':List_to_Str(c),'attribute':'界符','line_num':line} CL.append(token) del (c[-2],c[-1]) #如果不是，则退回一个字符，返回> else: i = i-1 del(c[-1]) print('符号：',c[-1]) token = {'value':List_to_Str(c),'attribute':'界符','line_num':line} CL.append(token) del(c[-1]) elif c[-1]==' ': print(c[-1],'识别到空格') del c[-1] #如果时换行符，则跳过并行数加一 elif c[-1]=='\n': print('识别到换行符',c[-1]) line = line + 1 del(c[-1]) #如果啥都不是，则报错，并清空 else: print(c) print('出错字符:',c[-1]) print(c) del(c[-1]) print('_____________ERROR________________'+line) #下个单词的首字符 i =i + 1 fp = open('rr.txt','w') fp.write(str(CL)) print(CL)下面是语法分析： 根据上机练习一给出的PL/0语言扩充的巴克斯范式语法描述，利用递归下降的语法分析方法，编写PL/0语言的语法分析程序。 要求：
对给出的PL/0语言进行分析，证明其可以进行自上而下的语法分析；对block、proc、statement、condition、expression、term、factor进行分析，画出语法分析图，在此基础上描述这些子程序的设计思想；具有一定的语法错误处理能力；C++
#include <iostream> #include <fstream> #include <string> #include <cctype> #include <cstring> #include <stdio.h> #include <stdlib.h> #include <iomanip> using namespace std; int n=0; string a_line; int num = 0; // 结构体数组下标 struct yufa { string SYM; // 单词的类别 string strToken; // 用户所定义的标识符的值 int line; // 记录换行符的个数，即记录源文件的行数 }temp,yufa[1000]; string reserve[15]={"begin", "end", "if", "then", "else", "while", "write", "read", "do", "call", "const", "var", "procedure", "program", "odd"}; bool isreserve(string s); void prog(); void block(); void _const_(); void body(); void statement(); void exp(); void term(); void factor(); void lexp(); int main(void) { fstream infile; infile.open("source1.txt",ios::in); if(infile.fail()) { cout<<"error"<<endl; exit(0); } int row = 1; //row代表行数 while(getline(infile,a_line,'\n')) //每次读取一行 { int column=0; //column代表这一行的第几列个字符 string temp; while(column<a_line.size()) { if(isalpha(a_line[column])) { int i=1; temp+=a_line[column]; while(isalpha(a_line[column+1])||isdigit(a_line[column+1])) { temp+=a_line[column+1]; column++; i++; } if(isreserve(temp)) { yufa[n].SYM = temp; yufa[n].strToken = temp; yufa[n].line = row; n++; cout<<"<"<<temp<<" , reserve"<<">"<<endl; } else { yufa[n].SYM = "biaoshifu"; yufa[n].strToken = temp; yufa[n].line = row; n++; cout<<"<"<<temp<<" , symbol"<<">"<<endl; } temp.erase(); } else if(isdigit(a_line[column])) { int i=1; temp+=a_line[column]; bool flag=0; while(isalpha(a_line[column+1])||isdigit(a_line[column+1])) { temp+=a_line[column+1]; if(isalpha(temp[i])) flag=1; column++; i++; } if(flag==0) { yufa[n].SYM = "digit"; yufa[n].strToken = temp; yufa[n].line = row; n++; cout<<"<"<<temp<<" , number"<<">"<<endl; } else //说明出现数字打头的保留字 cout<<"row: "<<row<<" column: "<<column<<" is error!"<<endl; temp.erase(); } else if(a_line[column]=='+'||a_line[column]=='-'||a_line[column]=='*'||a_line[column]=='/'||a_line[column]=='=') { temp+=a_line[column]; yufa[n].SYM = temp; yufa[n].strToken = temp; yufa[n].line = row; n++; cout<<"<"<<a_line[column]<<" , operator"<<">"<<endl; temp.erase(); } /* else if((a_line[column]=='/'&&a_line[column+1]=='*')||(a_line[column]=='*'&&a_line[column+1]=='/')) cout<<"<"<<a_line[column]<<a_line[column+1]<<" , bound symbol"<<">"<<endl;*/ else if(a_line[column]==';'||a_line[column]=='('||a_line[column]==')'||a_line[column]==',') { temp+=a_line[column]; yufa[n].SYM = temp; yufa[n].strToken = temp; yufa[n].line = row; n++; cout<<"<"<<a_line[column]<<" , bound symbol"<<">"<<endl; temp.erase(); } else if(a_line[column]==':') { if(a_line[column+1]=='=') { yufa[n].SYM = "fuzhi"; yufa[n].strToken = ":="; yufa[n].line = row; n++; cout<<"<"<<a_line[column]<<a_line[column+1]<<" , operator"<<">"<<endl; column++; } else cout<<"row: "<<row<<" column: "<<column<<" is error!"<<endl; temp.erase(); } else if(a_line[column]=='<') { if(a_line[column+1]=='=') { yufa[n].SYM = "le"; yufa[n].strToken = "<="; yufa[n].line = row; n++; cout<<"<"<<a_line[column]<<a_line[column+1]<<" , operator"<<">"<<endl; column++; } else if(a_line[column+1]=='>') { yufa[n].SYM = "ne"; yufa[n].strToken = "<>"; yufa[n].line = row; n++; cout<<"<"<<a_line[column]<<a_line[column+1]<<" , operator"<<">"<<endl; column++; } else { yufa[n].SYM = "l"; yufa[n].strToken = "<"; yufa[n].line = row; n++; cout<<"<"<<a_line[column]<<" , operator"<<">"<<endl; } temp.erase(); } else if(a_line[column]=='>') { if(a_line[column+1]=='=') { yufa[n].SYM = "ge"; yufa[n].strToken = ">="; yufa[n].line = row; n++; cout<<"<"<<a_line[column]<<a_line[column+1]<<" , operator"<<">"<<endl; column++; } else { yufa[n].SYM = "g"; yufa[n].strToken = ">"; yufa[n].line = row; n++; cout<<"<"<<a_line[column]<<" , operator"<<">"<<endl; } temp.erase(); } column++; } row++; } infile.close(); for(int i=0;i<n;i++) { cout<<yufa[i].line<<"\t"<<yufa[i].SYM<<"\t"<<yufa[i].strToken<<endl; } prog(); for(int i = 0;i<n-1;i++) { if(yufa[i].SYM == ")"&&yufa[i+1].SYM !=";") cout<<"line"<<yufa[i].line<<": 分号缺失"<<endl; if(yufa[i].SYM == "("&&yufa[i+1].SYM == ")") cout<<"line"<<yufa[i].line<<": 函数内变量缺失"<<endl; } system("pause"); return 0; } bool isreserve(string s) { for(int i = 0;i<15;i++) { if(s.compare(reserve[i]) == 0) return true; } return false; } /*<prog> → program <id>；<block>*/ void prog() { temp = yufa[num]; cout<<"进入 prog 模块"<<endl; if(temp.SYM!="program") { num++; temp = yufa[num]; if(temp.SYM!=";") { cout<<"line"<<temp.line<<": program 拼写错误"<<endl; } else { num--; cout<<"line"<<temp.line<<": program 缺失"<<endl; } } else { num++; } temp = yufa[num]; if(temp.SYM != "biaoshifu") { cout<<"line"<<temp.line<<": 标识符错误"<<endl; } else { num++; } temp = yufa[num]; if(temp.SYM!=";") { cout<<"line"<<temp.line-1<<": 分号缺失"<<endl; } else { num++; } cout<<"prog 模块结束"<<endl; block(); } /* <block> → [<condecl>][<vardecl>][<proc>]<body> <condecl> → const <const>{,<const>}; <vardecl> → var <id>{,<id>}; <proc> → procedure <id>（[<id>{,<id>]}）;<block>{;<proc>} */ void block() { cout<<"进入 block 模块"<<endl; temp = yufa[num]; if(temp.SYM == "const") { num++; _const_(); temp = yufa[num]; while(temp.SYM == ",") { num++; _const_(); temp = yufa[num]; } if(temp.SYM == ";") { num++; temp = yufa[num]; } else { temp = yufa[num-1]; cout<<"line"<<temp.line<<": 分号缺失"<<endl; } temp = yufa[num]; cout<<"const 模块结束"<<endl; } if(temp.SYM == "var") { cout<<"进入 var 模块"<<endl; num++; temp = yufa[num]; if(temp.SYM == "biaoshifu") { num++; temp = yufa[num]; } else { cout<<"line"<<temp.line<<": 缺少变量声明"<<endl; } while(temp.SYM == ",") { num++; temp = yufa[num]; if(temp.SYM == "biaoshifu") { num++; temp = yufa[num]; } else { cout<<"line"<<temp.line<<": 逗号后变量缺失"<<endl; } } if(temp.SYM == ";") { num++; temp = yufa[num]; } else { temp = yufa[num-1]; cout<<"line"<<temp.line<<": 分号缺失"<<endl; num++; } cout<<"var 模块结束"<<endl; } while(temp.SYM == "procedure") { cout<<"进入 procedure 模块"<<endl; num++; temp = yufa[num]; if(temp.SYM == "biaoshifu") { num++; temp = yufa[num]; if(temp.SYM == "(") { num++; temp = yufa[num]; if(temp.SYM == "biaoshifu") { num++; temp = yufa[num]; } while(temp.SYM == ",") { num++; temp = yufa[num]; if(temp.SYM == "biaoshifu") { num++; temp = yufa[num]; } } if(temp.SYM == ")") { num++; } else { cout<<"line"<<temp.line<<": 右括号缺失"<<endl; } } else { cout<<"line"<<temp.line<<": 左括号缺失"<<endl; } } else { cout<<"line"<<temp.line<<": 函数名错误"<<endl; } temp = yufa[num]; if(temp.SYM != ";") { cout<<"line"<<temp.line<<": 分号缺失"<<endl; } else { num++; } block(); temp = yufa[num]; if(temp.SYM == ";") { num++; temp = yufa[num]; } else { break; } } body(); cout<<"block 模块结束"<<endl; } /*<body> → begin <statement>{;<statement>}end*/ void body() { cout<<"进入 body 模块"<<endl; int k=0; temp = yufa[num]; //cout<<temp.SYM; /*if(temp.SYM!="begin") { num++; cout<<"line"<<temp.line<<" begin is missed"<<endl; } else { num++; }*/ if(temp.SYM == "begin") { for(int i = num;i<n;i++) if(yufa[i].SYM == "end") k++; if(k == 0) cout<<"line"<<temp.line<<": begin 的 end 缺失"<<endl; } /*else if(temp.SYM != "begin") { cout<<"line"<<temp.line<<"begin缺失"<<endl; }*/ num++; statement(); temp = yufa[num]; while(temp.SYM == ";") { num++; temp = yufa[num]; if(temp.SYM == "end") { break; } else { statement(); temp = yufa[num]; } } if(temp.SYM != "end") { //cout<<"line"<<temp.line<<" end is missed"<<endl; } else num++; cout<<"body 模块结束"<<endl; } /* <statement> → <id> := <exp> |if <lexp> then <statement>[else <statement>] |while <lexp> do <statement> |call <id>（[<exp>{,<exp>}]） |<body> |read (<id>{，<id>}) |write (<exp>{,<exp>}) */ void statement() { cout<<"进入 statement 模块"<<endl; temp = yufa[num]; //cout<<temp.line<<temp.strToken<<endl; if(temp.SYM == "biaoshifu") { num++; temp = yufa[num]; //cout<<temp.SYM<<endl; if(temp.SYM != "fuzhi") { //cout<<"line"<<temp.line<<": 赋值符缺失"<<endl; } else num++; exp(); } else if(temp.SYM == "if") { cout<<"进入 if 模块"<<endl; num++; lexp(); temp = yufa[num]; if(temp.SYM != "then") { cout<<"line"<<temp.line<<": then缺失"<<endl; } else num++; statement(); temp = yufa[num]; if(temp.SYM == "else") { statement(); temp = yufa[num]; if(temp.SYM!=";") cout<<"line"<<temp.line<<": 分号缺失"<<endl; else num++; } } else if(temp.SYM == "while") { cout<<"进入 while 模块"<<endl; num++; lexp(); temp = yufa[num]; if(temp.SYM != "do") { cout<<"line"<<temp.line<<": do缺失"<<endl; } else { num++; statement(); } cout<<"while 结束"<<endl; } else if(temp.SYM == "call") { cout<<"进入 call 模块"<<endl; num++; temp = yufa[num]; if(temp.SYM != "biaoshifu") { cout<<"line"<<temp.line<<": 函数名错误"<<endl; } else { num++; temp = yufa[num]; if(temp.SYM != "(") cout<<"line"<<temp.line<<": 右括号缺失"<<endl; else num++; exp(); temp = yufa[num]; while(temp.SYM == ",") { num++; temp = yufa[num]; exp(); temp = yufa[num]; } if(temp.SYM != ")") { cout<<"line"<<temp.line<<": 左括号缺失"<<endl; } else num++; } } else if(temp.SYM == "read") { cout<<"进入 read 模块"<<endl; num++; temp = yufa[num]; if(temp.SYM != "(") cout<<"line"<<temp.line<<": 左括号缺失"<<endl; else num++; temp = yufa[num]; if(temp.SYM != "biaoshifu") cout<<"line"<<temp.line<<": 变量缺失"<<endl; else num++; temp = yufa[num]; while(temp.SYM == ",") { num++; temp = yufa[num]; if(temp.SYM == "biaoshifu") { num++; temp = yufa[num]; } else cout<<"line"<<temp.line<<": 逗号后变量缺失"<<endl; } if(temp.SYM != ")") cout<<"line"<<temp.line<<": 右括号缺失"<<endl; else num++; } else if(temp.SYM == "write") { cout<<"进入 write 模块"<<endl; num++; temp = yufa[num]; //cout<<temp.SYM<<endl<<endl<<endl; if(temp.SYM != "(") { cout<<"line"<<temp.line<<": 左括号缺失"<<endl; } else num++; exp(); temp = yufa[num]; while(temp.SYM == ",") { num++; exp(); temp = yufa[num]; } if(temp.SYM != ")") cout<<"line"<<temp.line<<": 右括号缺失"<<endl; else num++; cout<<"write 模块结束"<<endl; } else cout<<"statement 模块结束"<<endl; } /*<exp> → [+|-]<term>{<aop><term>}*/ void exp() { cout<<"进入 exp 模块"<<endl; temp = yufa[num]; if(temp.SYM == "+"|| temp.SYM == "-") { num++; term(); } else term(); temp = yufa[num]; while(temp.SYM == "+"|| temp.SYM == "-") { num++; term(); temp = yufa[num]; } cout<<"exp 模块结束"<<endl; } /*<term> → <factor>{<mop><factor>}*/ void term() { cout<<"进入 term 模块"<<endl; factor(); temp = yufa[num]; while(temp.SYM == "*"|| temp.SYM == "/") { num++; factor(); temp = yufa[num]; } cout<<"term 模块结束"<<endl; } /*<factor>→<id>|<integer>|(<exp>)*/ void factor() { cout<<"进入 factor 模块"<<endl; temp = yufa[num]; if(temp.SYM == "biaoshifu") num++; else if(temp.SYM == "digit") num++; else if(temp.SYM == "(") { num++; exp(); temp = yufa[num]; if(temp.SYM != ")") cout<<"line"<<temp.line<<": 右括号缺失"<<endl; } cout<<"factor 模块结束"<<endl; } /*<lexp> → <exp> <lop> <exp>|odd <exp>*/ void lexp() { cout<<"进入 lexp 模块"<<endl; temp = yufa[num]; if(temp.SYM == "odd") { exp(); } else { exp(); temp = yufa[num]; if(temp.SYM!="="&&temp.SYM!="ne"&&temp.SYM!="l"&&temp.SYM!="le"&&temp.SYM!="g"&&temp.SYM!="ge") cout<<"line"<<temp.line<<": 比较运算符缺失"<<endl; else num++; exp(); cout<<"lexp 模块结束"<<endl; } } /*<const> → <id>:=<integer>*/ void _const_() { cout<<"进入 const 模块"<<endl; temp = yufa[num]; if(temp.SYM == "biaoshifu") { num++; temp = yufa[num]; if(temp.SYM == "fuzhi") { num++; temp = yufa[num]; if(temp.SYM == "digit") { num++; } else { temp = yufa[num-1]; cout<<"line"<<temp.line<<": 赋值符号后不是数字"<<endl; } } else { cout<<"line"<<temp.line<<": 赋值符缺失"<<endl; } } else { cout<<"line"<<temp.line<<": 标识符错误"<<endl; } cout<<"const 模块结束"<<endl; }Python 室友一
#语法分析的任务： #根据文法产生式，判断给定的输入符号串是否为一个句子 index = 0 ERROR= [] #错误信息列表 def get_token(): global index if index < len(CL): return CL[index] else: print('分析完成') # <prog> → program <id>；<block> def prog(): global index token = get_token() print('进入prog分析') if token['value'] != 'program': # 第一个单词不是program，两种错误，拼写或缺失错误 index = index + 1 token = get_token() if token['value'] != ';': #拼写错误 print('出错行数：',token['line_num'], '\t\t错误原因：program拼写错误') else: #缺失错误 index = index - 1 print('出错行数：',token['line_num'], '\t\t错误原因：缺少program关键字') else: index = index + 1 token = get_token() if token['attribute'] != 'identifier': # 第二个是程序名称 print('出错行数：',token['line_num'], '\t\t出错原因：语法错误,缺少程序名称') else: index = index + 1 token = get_token() if token['value'] != ';': # 第三个是分号 然后进入block阶段 print('出错行数：',token['line_num'], '\t\t出错原因：缺少;') else: index = index + 1 print('prog___________________over') block() # <block> → [<condecl>][<vardecl>][<proc>]<body> # 考虑到因为;缺失导致获取的下一个单词不方便放回去，所以condecl vardecl proc在block层进行解析 def block(): # 常量表达式 <condecl> → const <const>{,<const>}; print('进入block分析') global index token = get_token() if token['value'] == 'const': index = index + 1 const() token = get_token() while token['value'] == ',': index = index + 1 const() token = get_token() if token['value'] == ';': index = index + 1 token = get_token() else: print('出错行数：',token['line_num'], '\t\t错误原因：缺少 ;') # 变量表达式 <vardecl> → var <id>{,<id>}; if token['value'] == 'var': print('进入变量分析') index = index + 1 token = get_token() if token['attribute'] == 'identifier': index = index + 1 token = get_token() else: print('出错行数：',token['line_num'], '\t\t错误原因：var后缺少变量声明') while token['value'] == ',': index = index + 1 token = get_token() if token['attribute'] == 'identifier': index = index + 1 token = get_token() if token['value'] == ';': index = index + 1 token = get_token() else: print('出错行数：',token['line_num'], '\t\t错误原因：缺少 ;') print('变量分析完成') # 这里用while循环表示函数定义可以嵌套 # 函数定义 <proc> → procedure <id>（[<id>{,<id>}]）;<block>{;<proc>} while token['value'] == 'procedure': print('进入函数分析（---------------procedure）') index = index + 1 token = get_token() if token['attribute'] != 'identifier': print('出错行数：',token['line_num'], '\t\t出错原因：函数名必须是标识符') else: index = index + 1 token = get_token() if token['value'] != '(': print('出错行数：',token['line_num'], '\t\t出错原因 :缺少(') else: index = index + 1 token = get_token() if token['attribute'] != 'identifier': print('出错行数：',token['line_num'], '\t\t出错原因 :缺少函数参数') else: index = index + 1 token = get_token() #[<id>{,<id>}] while token['value'] == ',': index = index + 1 token = get_token() if token['attribute'] == 'identifier': index = index + 1 token = get_token() if token['value'] != ')': print('出错行数：',token['line_num'], '\t\t出错原因 :缺少 )') else: index = index + 1 token = get_token() if token['value'] != ';': #当产生错误时，index不再前进，报错后继续向后分析 print('出错行数：',token['line_num'], '\t\t出错原因：缺少;') else: index = index + 1 # 下面进入block定义 进入block之前需要更新嵌套层数level 同时记录当前栈的情况便于恢复 block() token = get_token() if token['value'] == ';': # 如果是分号 继续进行proc index = index + 1 token = get_token() elif token['value'] != 'procedure': break elif token['value'] == 'procedure': print('出错行数：',token['line_num'], '\t\t出错原因：缺少;') #<body> body() print('block分析完成') # <const> → <id>:=<integer> def const(): print('进入常量分析') global index token = get_token() if token['attribute'] != 'identifier': # 这里有变量 需要记录在符号表中 print(token['line_num'], '缺少标识符') else: index = index + 1 token = get_token() if token['value'] != ':=': print('出错行数：',token['line_num'], '\t\t出错原因：缺少:=') else: index = index + 1 token = get_token() if token['attribute'] != 'number': print('出错行数：',token['line_num'], '\t\t出错原因：:=后面需要跟整数') else: index = index + 1 print('常量分析完成') # <body> → begin <statement>{;<statement>}end def body(): print('进入body分析') global index token = get_token() if token['value'] != 'begin': index = index + 1 print('出错行数：',token['line_num'], '\t\t出错原因：缺少begin') else: index = index + 1 statement() token = get_token() #??????????????????????处理缺失的;???????????????????????? while token['value']==';' or is_statement()==True: # 循环statement if token['value']!=';': prior = index - 1 if CL[prior]['value']!='end': print('出错行数：',token['line_num'], '\t\t出错原因：缺少 ;') else: index = index + 1 statement() token = get_token() print(token['value']) print('55555555555555555555555555555555555555555555555') token = get_token() if token['value'] != ';': print('出错行数：',token['line_num'], '\t\t出错原因：缺少;') else: index = index + 1 token =get_token() if token['value'] != 'end': print('出错行数：',token['line_num'], '\t\t出错原因：缺少end') else: print('识别到end') index = index + 1 print('body分析完成') # <statement> → <id> :=<exp>; # |if <lexp> then <statement>[else <statement>] # |while <lexp> do <statement> # |call <id>（[<exp>{,<exp>}]） # |<body> # |read (<id>{，<id>}) # |write (<exp>{,<exp>}) def is_statement(): token = get_token() if token['value'] in ['if','while','call','read','write','begin']: return True elif token['attribute'] == 'identifier': return True else: return False def statement(): global index ''' if token['value'] == 'end': # 这一步是因为如果最后有人多写了一个; 会继续进入statement,但实际上会退出 error(token['line_num'], ';是多余的') token_index -= 1 return ''' # <id> := <exp> print('进入statement分析') token = get_token() print('statement识别到',token['value']) #print(token['value'],'44444444444444444444444444') if token['attribute'] == 'identifier': index = index + 1 token = get_token() if token['value'] != ':=': print('出错行数：',token['line_num'],'\t\t出错原因：缺少：=') else: #print(token['value'],'5555555555555555555555555555555555555') index = index + 1 #print(token['value'],'66666666666666666666666666') expression() # if <lexp> then <statement>[else <statement>] elif token['value'] == 'if': print('进入if语句分析') index = index + 1 lexp() token = get_token() # print('____________________当前token',token) if token['value'] != 'then': print('出错行数：',token['line_num'], '\t\t出错原因：缺少关键字then') else: print('_____________识别到then___________') index = index + 1 statement() token = get_token() print('dangqian',token['value']) if token['value'] == 'else': statement() token = get_token() if token['value']!=';': print('出错行数：',token['line_num'],'\t\t出错原因：缺少 ; ') else: index = index + 1 # while <lexp> do <statement> elif token['value'] == 'while': print('进入while语句分析') index = index + 1 lexp() token = get_token() if token['value'] != 'do': print('出错行数：',token['line_num'], '\t\t出错原因：缺少do关键字') else: index = index + 1 statement() print('while语句分析完成') # call <id>（[<exp>{,<exp>}]） elif token['value'] == 'call': print('进入call==========================') index = index + 1 token = get_token() if token['attribute'] != 'identifier': print('出错行数：',token['line_num'], '\t\t出错原因：函数名必须是标识符') else: print('识别到',token['value']) index = index + 1 token = get_token() if token['value']!='(': print('出错行数：',token['line_num'],'\t\t出错原因：缺少（') else: print('识别到',token['value']) index = index + 1 #????????????????????????????????????? token = get_token() print('识别到===========+++++++++',token['value']) if token['value']==')': print('识别到-----------',token['value']) else: expression() while token['value']==',': print(token['value'],11111111111111111111111111111) index = index + 1 expression() token = get_token() token = get_token() if token['value'] != ')': print(token['value'],'errrrrrrrrrrrrrrrrrrrrrrrrrrr') print('出错行数：',token['line_num'],'\t\t出错原因：缺少 )') else: index = index + 1 #read (<id>{，<id>}) elif token['value'] == 'read': print('进入read语句分析') index = index + 1 token = get_token() if token['value'] != '(': print('出错行数：',token['line_num'],'\t\t出错原因：缺少（') else: print('识别到 _________(____________') index = index +1 token = get_token() if token['attribute'] !='identifier': print('出错行数：',token['line_num'],'\t\t出错原因：缺少变量') else: print('识别到',token['value']) index = index + 1 token = get_token() while(token['value'] == ','): index = index + 1 token = get_token() if token['attribute'] != 'identifier': print('出错行数：',token['line_num'],'\t\t出错原因：,后缺少变量') else: print('识别到',token['value']) if index !=len(CL)-1: index = index + 1 token = get_token() if token['value'] !=')': print('出错行数：',token['line_num'],'\t\t出错原因：缺少 ）') else: print('识别到',token['value']) index = index + 1 print('read分析完成') # write (<exp>{,<exp>}) elif token['value'] == 'write': print('进入write语句分析-------------------------------------') index = index + 1 token = get_token() if token['value'] !='(': print('出错行数：',token['line_num'],'\t\t出错原因：write后缺少（') else: index = index + 1 expression() token = get_token() while token['value'] == ',': index = index + 1 expression() token = get_token() if token['value'] !=')': print('出错行数：',token['line_num'],'\t\t出错原因:缺少）') else: index = index + 1 print('write语句分析完成') # body elif token['value']=='begin': print('----------------------------------再次进入body分析-----------------------------------------------') body() print('statement分析完成') # <exp> → [+|-]<term>{<aop><term>} def expression(): print('进入expression分析') global index token = get_token() #print(token['value'],'44444444444444444444444444') if token['value'] == '+' or token['value'] == '-': index = index + 1 term() else: term() token = get_token() while token['value'] == '+' or token['value'] == '-': print('识别到',token['value']) index = index + 1 term() token = get_token() print('expression分析完成') # <term> → <factor>{<mop><factor>} def term(): print('进入term分析') global index factor() token = get_token() # 处理乘除 while token['value'] == '*' or token['value'] == '/': index = index + 1 factor() token = get_token() print('term分析完成') # <factor>→<id>|<integer>|(<exp>) def factor(): print('进入factor分析') global index token = get_token() if token['attribute'] == 'identifier': print('识别到变量',token['value']) index = index + 1 elif token['attribute'] == 'number': # 遇到数字 print('识别到',token['value']) index = index + 1 elif token['attribute'] == '(': # 遇到左括号要进入表达式 index = index + 1 expression() token = get_token() if token['attribute'] != ')': # 没有右括号报错 print('出错行数：',token['line_num'], '\t\t出错原因：缺少 ）') else: print('出错行数：',token['line_num'],'\t\t出错原因：此处缺少factor') print('factor分析完成') #?????????????????????????????????????????????????????? # <lexp> → <exp> <lop> <exp>|odd <exp> # <lop> → =|<>|<|<=|>|>= def lexp(): print('进入lexp分析') global index token = get_token() if token['value'] == 'odd': expression() else: expression() token = get_token() # <lop> → =|<>|<|<=|>|>= if token['value'] != '=' and token['value'] != '<>' and token['value'] != '<' and token['value'] != '<=' \ and token['value'] != '>' and token['value'] != '>=': print('出错行数：',token['line_num'], '\t\t出错原因：缺少比较运算符') else: print('识别到比较运算符',token['value']) index = index + 1 expression() print('lexp分析完成') try: prog() except: if index ==len(CL): if CL[index-1]['value'] !='end': print('出错行数：',index-1, '\t\t出错原因：缺少end') print('__________________________________分析完成_____________________________') else: print('unkown error index = ',index) ''' <block> → [<condecl>][<vardecl>][<proc>]<body> <condecl> → const <const>{,<const>}; <const> → <id>:=<integer> <vardecl> → var <id>{,<id>}; <proc> → procedure <id>（[<id>{,<id>]}）;<block>{;<proc>} <body> → begin <statement>{;<statement>}end <statement> → <id> := <exp> |if <lexp> then <statement>[else <statement>] |while <lexp> do <statement> |call <id>（[<exp>{,<exp>}]） |<body> |read (<id>{，<id>}) |write (<exp>{,<exp>}) <lexp> → <exp> <lop> <exp>|odd <exp> <exp> → [+|-]<term>{<aop><term>} <term> → <factor>{<mop><factor>} <factor>→<id>|<integer>|(<exp>) <lop> → =|<>|<|<=|>|>= <aop> → +|- <mop> → *|/（**//） <id> → l{l|d} （注：l表示字母） <integer> → d{d} 注释： <prog>：程序 ；<block>：块、程序体 ；<condecl>：常量说明 ；<const>：常量； <vardecl>：变量说明 ；<proc>：分程序 ； <body>：复合语句 ；<statement>：语句； <exp>：表达式 ；<lexp>：条件 ；<term>：项 ； <factor>：因子 ；<aop>：加法运算符； <mop>：乘法运算符； <lop>：关系运算符 odd：判断表达式的奇偶性。 '''室友二
def keep(a,k,i): if a[k:i] in save: return 1 else: return 0 save=['write','read','call','program','function','procedure','array','const','file','label','of','packed','record','set','type','var','case','do','downto','else','for','forward','goto','if','repeat','then','to','until','while','with','and','div','in','mod','not','or','begin','end','nil','readln'] get1=[] with open('1.txt','r',encoding='utf-8') as f: a=f.read() i=0 while i<len(a): b=a if b[i]==' ' or b[i]=='\n': pass else: k=i #print(b[k]) if b[i].isalpha(): c=b while c[i].isalpha() or c[i].isdigit(): i=i+1 if i==len(c): break; #print(i) if keep(b,k,i): get1.append("保留字:"+b[k:i]) i=i-1 else: get1.append("变量:"+b[k:i]) i=i-1 else: if b[i].isdigit(): while b[i].isdigit(): i=i+1 if i==len(c): break; get1.append("常量:"+b[k:i]) i=i-1 else: if b[i]==':': if b[i+1]=='=': i=i+1 get1.append("符号:"+b[k:i+1]) else: get1.append("符号:"+b[k:i+1]) elif b[i]=='>': if b[i+1]=='=': i=i+1 get1.append("符号:"+b[k:i+1]) else: get1.append("符号:"+b[k:i+1]) elif b[i]=='<': if b[i+1]=='=': i=i+1 get1.append("符号:"+b[k:i+1]) else: get1.append("符号:"+b[k:i+1]) elif b[i]=='<': if b[i+1]=='>': i=i+1 get1.append("符号:"+b[k:i+1]) else: get1.append("符号:"+b[k:i+1]) else: get1.append("符号:"+b[k:i+1]) i=i+1 print(get1) def printii(get1): i=0 while i<len(get1): if get1[i]!="符号::=": print(get1[i].split(':')[1],end=' ') else: print(":=",end=' ') i=i+1 print('\n') def p1(get1): if p21(get1): return False if p22(get1): return False if p23(get1): return False if block(get1): return False return True def p21(get1): #print(get1[0].split(':')[1]) if get1[0].split(':')[1]=='program': get1.pop(0) return False else: return True def p22(get1): if get1[0].split(':')[0]=='变量': get1.pop(0) return False else: return True def p23(get1): if get1[0].split(':')[1]==';': get1.pop(0) return False else: return True def block(get1):#匹配成功返回False if get1[-1]!='保留字:end': return True i=len(get1)-2 j=1 while i>=0 and j!=0: if get1[i]=='保留字:begin': j=j-1 elif get1[i]=='保留字:end': j=j+1 i=i-1 if i==-1 and j!=0: return True i=i+1 get2=get1[0:i] get3=get1[i:len(get1)] #print(get2) #print(get3) if convar(get2) and body(get3): return False return True def convar(get2):#匹配成功返回True while len(get2)>0: get2i=[] while len(get2)>0: if get2[0]!='符号:;': get2i.append(get2[0]) get2.pop(0) else: get2.pop(0) break printii(get2i) #print(proc(get2i)) if proc(get2i): #print(block(get2)) return not block(get2) get2=[] if condec(get2i) or vardec(get2i):#匹配成功返回真 continue else: return False return True def condec(get2i): get2j=[] j=0 while j<len(get2i): get2j.append(get2i[j]) j=j+1 if get2j[0]=='保留字:const': get2j.pop(0) else: return False ### i=0 while i<len(get2j): if i%4==0 and get2j[i].split(':')[0]=="变量": i=i+1 continue if i%4==1 and get2j[i]=="符号::=": i=i+1 continue if i%4==2 and get2j[i].split(':')[0]=="常量": i=i+1 continue if i%4==3 and get2j[i].split(':')[1]==",": i=i+1 continue return False return True def vardec(get2i): get2j=[] j=0 while j<len(get2i): get2j.append(get2i[j]) j=j+1 if get2j[0]=='保留字:var': get2j.pop(0) else: return False i=0 while i<len(get2j): if i%2==0 and get2j[i].split(':')[0]=="变量": i=i+1 continue if i%2==1 and get2j[i].split(':')[1]==",": i=i+1 continue return False return True def proc(get2i): get2j=[] j=0 while j<len(get2i): get2j.append(get2i[j]) j=j+1 if len(get2j)>3 and get2j[0]=='保留字:procedure' and get2j[1].split(':')[0]=="变量" and get2j[2]=='符号:(': get2j.pop(0) get2j.pop(0) get2j.pop(0) else: return False #print(get2j) i=0 while i<len(get2j) and get2j[i]!='符号:)': if i%2==0 and get2j[i].split(':')[0]=="变量": i=i+1 continue if i%2==1 and get2j[i]=="符号:,": i=i+1 continue return False #print(get2j[i]) if get2j[i]=='符号:)': return True else: return False ''' get2j=get2j[i+1:len(get2i)] j=0 while get2j[j]!="保留字:procedure"&j<len(get2j): j=j+1 if get2j[j-1]!="符号:;": get2m=get2j[0:j-1] get2n=get2j[j:len(get2j)] block(get2m) proc(get2n) else: return False ''' def body(get3):#匹配成功返回True if get3[0]=='保留字:begin' and get1[-1]=='保留字:end': get3.pop(0) get3.pop(-1) else: return False while len(get3)>0: get3i=[] while len(get3)>0: if get3[0]!='符号:;': get3i.append(get3[0]) get3.pop(0) else: get3.pop(0) break printii(get3i) if statement(get3i): continue else: return False return True def statement(get3i): if stat1(get3i) or stat2(get3i) or stat3(get3i) or stat4(get3i) or stat5(get3i) or stat6(get3i) or stat7(get3i):#匹配成功返回真 return True else: return False def stat1(get2i): get3i=[] j=0 while j<len(get2i): get3i.append(get2i[j]) j=j+1 if get3i[0].split(':')[0]=="变量" and get3i[1]=="符号::=": get3i.pop(0) get3i.pop(0) else: return False #time.sleep(4) return exp(get3i) def stat2(get2i): get3i=[] j=0 while j<len(get2i): get3i.append(get2i[j]) j=j+1 if get3i[0]=="保留字:if": get3i.pop(0) else: return False j=0 while j<len(get3i) and get3i[j]!="保留字:then": j=j+1 if j==len(get3i): return False else: get3j=get3i[0:j] get3k=get3i[j:len(get3i)] if lexp(get3j): pass else: return False get3k.pop(0) j=0 while j<len(get3k) and get3k[j]!="保留字:else": j=j+1 if j==len(get3k): return statement(get3k) else: get3m=get3k[0:j] get3n=get3k[j+1:len(get3k)] #print(get3m) #print(statement(get3m)) if statement(get3m) and statement(get3n): return True else: return False def stat3(get2i): get3i=[] j=0 while j<len(get2i): get3i.append(get2i[j]) j=j+1 if get3i[0]=="保留字:while": get3i.pop(0) else: return False j=0 while j<len(get3i) and get3i[j]!="保留字:do": j=j+1 if j==len(get3i): return False else: get3m=get3i[0:j] get3n=get3i[j+1:len(get3i)] #print(get3n) #print(statement(get3n)) if lexp(get3m) and statement(get3n): return True else: return False def stat4(get2i): get3i=[] j=0 while j<len(get2i): get3i.append(get2i[j]) j=j+1 if len(get3i)>=3 and get3i[0]=="保留字:call" and get3i[1].split(':')[0]=="变量" and get3i[2]=="符号:(" and get3i[len(get3i)-1]=="符号:)": get3i.pop(0) get3i.pop(0) get3i.pop(0) get3i.pop(len(get3i)-1) else: return False #print(get3i) while len(get3i)>0: get3j=[] while len(get3i)>0: if get3i[0]!='符号:,': get3j.append(get3i[0]) get3i.pop(0) else: get3i.pop(0) break if exp(get3j): continue else: return False return True def stat5(get2i): get3i=[] j=0 while j<len(get2i): get3i.append(get2i[j]) j=j+1 return body(get3i) def stat6(get2i): get3i=[] j=0 while j<len(get2i): get3i.append(get2i[j]) j=j+1 if len(get3i)>3 and get3i[0]=="保留字:read" and get3i[1]=="符号:(" and get3i[len(get3i)-1]=="符号:)": get3i.pop(0) get3i.pop(0) get3i.pop(len(get3i)-1) else: return False while len(get3i)>0: get3j=[] while len(get3i)>0: if get3i[0]!='符号:,': get3j.append(get3i[0]) get3i.pop(0) else: get3i.pop(0) break if len(get3j)==1 and get3j[0].split(':')[0]=="变量": continue else: return False return True def stat7(get2i): get3i=[] j=0 while j<len(get2i): get3i.append(get2i[j]) j=j+1 if get3i[0]=="保留字:write" and get3i[1]=="符号:(" and get3i[len(get3i)-1]=="符号:)": get3i.pop(0) get3i.pop(0) get3i.pop(len(get3i)-1) else: return False if len(get3i)==0: return False while len(get3i)>0: get3j=[] while len(get3i)>0: if get3i[0]!='符号:,': get3j.append(get3i[0]) get3i.pop(0) else: get3i.pop(0) break if exp(get3j): continue else: return False return True def lexp(get1): #print(get1) get2i=[] j=0 while j<len(get1): get2i.append(get1[j]) j=j+1 if get2i[0]=='odd': get1.pop(0) return exp(get2i) else: get3i=[] j=0 while j<len(get2i): get3i.append(get2i[j]) j=j+1 while len(get3i)>0: get3j=[] while len(get3i)>0: if lop(get3i[0]): get3i.pop(0) break else: get3j.append(get3i[0]) get3i.pop(0) if exp(get3j): continue else: return False return True def exp(get2i): get3i=[] j=0 while j<len(get2i): get3i.append(get2i[j]) j=j+1 while len(get3i)>0: get3j=[] while len(get3i)>0: if get3i[0]!='符号:+' and get3i[0]!='符号:-': get3j.append(get3i[0]) get3i.pop(0) else: get3i.pop(0) break if len(get3j)>0 and term(get3j): continue else: return False return True def term(get2i): get3i=[] j=0 while j<len(get2i): get3i.append(get2i[j]) j=j+1 while len(get3i)>0: get3j=[] while len(get3i)>0: if get3i[0]!='符号:*' and get3i[0]!='符号:/': get3j.append(get3i[0]) get3i.pop(0) else: get3i.pop(0) break if len(get3j)>0 and factor(get3j): continue else: return False return True def factor(get1): if len(get1)==1 and (get1[0].split(':')[0]=="变量" or get1[0].split(':')[0]=="常量"): return True else: return False def lop(get1): if get1=='符号:>' or get1=='符号:<' or get1=='符号:<>' or get1=='符号:<=' or get1=='符号:>=' or get1=='符号:=': return True else: return False print(p1(get1))C++测试文件（source.txt）错误自己添加
program xi; const a:=5; var j,sum,x; procedure sum1(x); begin while j<=5 do write (x); if j <=1 then read (x); write (x); call sum1(j+1); write(x); endPython测试文件1（3.txt）错误自己添加
program xi; const a:=5; var j,sum,x; procedure sum1(x); begin j:=1; sum:=0; while j<=x do write(sum); read(x); write(x); begin read(j); write(j); write(x); end read(j); write(j); call sum1(j+5); write(j); endPython测试文件2（1.txt）错误自己添加
program xi; const a:=5; var j,sum,x; procedure sum1(x); begin if a>b1 then while j<=x write (sum) else call sum1(j + 5) end begin j:=1; sum:=0; read(x); write(x); read(j); write(j); call s (j+5); write(j) end以上代码可跑通，但可能有Bug，我觉得明年NUAA的学弟学妹可能用得到哈哈哈！加油！
