说明：
分析的语言是SNL语言，详见《编译程序的设计与实现》（ 刘磊、金英、张晶、张荷花、单郸编著）
词法分析就是实现了词法分析的自动机
语法分析使用递归下降法
运行结果：
词法分析 得到TokenList
语法分析 输出语法树
运行输出：
代码：
main.cpp
#include<stdio.h>
#include<stdlib.h>
#include<vector>
#include<string.h>
using namespace std;
#define NUMOFRESERVED 22
#define NUMOFSYMBOLS 20
#define RES 0
#define ID 1
#define NUM 2
#define SYM 3
#define STR 4 #define PLUS 100
#define SUB 101
#define MUL 102
#define DIV 103
#define LT 104
#define LBRACK 105
#define RBRACK 106
#define LSQUBRACK 107
#define RSQUBRACK 108
#define POINT 109
#define SEMI 110
#define LBRACE 111
#define RBRACE 112
#define EOFF 113
#define BLANK 114
#define QUO 115
#define EQU 116
#define INDEX 117
#define ASSI 118
#define COM 119 #define uint unsigned typedef struct Token {
int id;
int ptr;
int linenum;
} Token;
typedef struct Node {
char *desc;
vector<Node*> children;
Node(const char* str) {
desc=new char[];
strcpy(desc,str);
}
} Node; vector<Token>* tokens;
int Token_n=;
const char* reserved_words[NUMOFRESERVED]= {"begin","end","program","var",
"type","procedure","while","endwh",
"integer","char","array","of",
"intc","record","if","then",
"else","fi","do","write",
"read","return"
}; static const char* symbol_table[NUMOFSYMBOLS]= {"+","-","*","/","<",
"(",")","[","]",".",
";","{","}","EOF","BLANK",
"\'","=","..",":=",","
};
void syntaxError(const char* message);
Node* MatchRES(const char* expected);
Node* MatchSYM(const int expected);
Node* MatchID();
Node* MatchNUM();
bool isRES(const char* res);
bool isSYM(const int res);
bool isID();
bool isNUM();
bool isLineEnd();
Node* Program();
Node* ProgramHead();
Node* DeclarePart();
Node* TypeDec();
Node* TypeDeclaration();
Node* TypeDecList();
Node* TypeDecMore();
Node* TypeId();
Node* TypeName();
Node* BaseType();
Node* StructureType();
Node* ArrayType();
Node* RecType();
Node* FieldDecList();
Node* FieldDecMore();
Node* IdList();
Node* IdMore();
Node* VarDec();
Node* VarDeclaration();
Node* VarDecList();
Node* VarDecMore();
Node* VarIdList();
Node* VarIdMore();
Node* ProcDec();
Node* ProcDeclaration();
Node* ParamList();
Node* ParamDecList();
Node* ParamMore();
Node* Param();
Node* FormList();
Node* FidMore();
Node* ProcDecPart();
Node* ProcBody();
Node* ProgramBody();
Node* StmList();
Node* StmMore();
Node* Stm();
Node* AssCall();
Node* AssignmentRest();
Node* ConditionalStm();
Node* LoopStm();
Node* InputStm();
Node* OutputStm();
Node* ReturnStm();
Node* CallStmRest();
Node* ActParamList();
Node* ActParamMore();
Node* Exp();
Node* Term();
Node* OtherFactor();
Node* OtherTerm();
Node* Factor();
Node* Variable();
Node* VariMore();
Node* FieldVar();
Node* FieldVarMore();
Node* Parse();
Node* CmpOp();
Node* AddOp();
Node* MultOp(); void show_tree(Node* root,int depth,vector<int>* v,bool islast); int add(vector<Node* >& children,Node* node) {
if(node!=NULL) {
children.push_back(node);
}
return ;
}
#define COMMENT_ERROR -1000
#define STR_ERROR -1001
#define SYM_ERROR -1002
#define NOT_REC_SYMBOL -1003
vector<char*> ID_table;
vector<uint> NUM_table;
vector<char*> STR_table;
int ID_n=,NUM_n=,STR_n=;
int num_of_lines=;
FILE * file; /***************************************************************************************/
/***************** 词法分析 *****************/
/***************************************************************************************/ void handle_error(int error_num,const char* str) {
printf("行号:%d \t",num_of_lines);
switch(error_num) {
case COMMENT_ERROR:
printf("注释未结束 \t");
break;
case SYM_ERROR:
printf("出现未定义的符号，您想输入的是\":=\"吗? \t");
break;
case STR_ERROR:
printf("字符串未结束 \t");
break;
case NOT_REC_SYMBOL:
printf("出现未定义的符号 \t");
break;
}
printf("%s\n",str);
exit(-);
}
char getNextChar() {
char c;
c=fgetc(file);
return c;
} void ungetNextChar() {
fseek(file,-,SEEK_CUR);
} int reservedLookup(char* str) {
for(int i=; i<NUMOFRESERVED; i++) {
if(strcmp(str,reserved_words[i])==)return i;
}
return -;
}
int str_to_num(char* str) {
int len=strlen(str);
int n=;
for(int i=; i<len; i++) {
n=n*+str[i]-'';
}
return n;
}
int addIDTable(char* str) {
ID_table.push_back(str);
return ID_n++;
}
int addNUMTable(int num) {
NUM_table.push_back(num);
return NUM_n++;
}
int addSTRTable(char* str ) {
STR_table.push_back(str);
return STR_n++;
}
Token scan() {
static const char symbols[]= {'+','-','*','/','<','(',')','[',']',';','=',','};
static const int symbols_n[]= {PLUS,SUB,MUL,DIV,LT,LBRACK,RBRACK,LSQUBRACK,RSQUBRACK,SEMI,EQU,COM};
Token t;
t.linenum=num_of_lines;
char* str=new char[];
strcpy(str,"");//字符串要初始化，不然有乱码
char c[]= {'a','\0'};
c[]=getNextChar();
LS0:
if(c[]>='a'&&c[]<='z')goto LS1;
if(c[]>='A'&&c[]<='Z')goto LS1;
if(c[]>=''&&c[]<='')goto LS2;
int indexofsym;
for(indexofsym=; indexofsym<; indexofsym++) {
if(c[]==symbols[indexofsym]) {
goto LS3;
}
}
if(c[]=='.')goto LS4;
if(c[]=='{')goto LS5;
if(c[]==':')goto LS6;
if(c[]=='\'')goto LS7;
if(c[]=='\n')goto LS8;
if(c[]==EOF)goto LS9;
if(c[]=='\t'||c[]==' ')goto LS10;
goto OTHER;
LS1:
strcat(str,c);
c[]=getNextChar();
if(c[]>='a'&&c[]<='z')goto LS1;
else if(c[]>='A'&&c[]<='Z')goto LS1;
else if(c[]>=''&&c[]<='')goto LS1;
ungetNextChar();
int nres;
if(nres=reservedLookup(str),nres!=-) {
t.id=RES;
t.ptr=nres;
return t;
} else {
t.id=ID;
t.ptr=addIDTable(str);
return t;
}
LS2:
strcat(str,c);
c[]=getNextChar();
if(c[]>=''&&c[]<='')goto LS2;
ungetNextChar();
t.id=NUM;
t.ptr=addNUMTable(str_to_num(str));
return t;
LS3:
t.ptr=symbols_n[indexofsym];
t.id=SYM;
return t;
LS4:
strcat(str,c);
c[]=getNextChar();
if(c[]=='.') {
t.id=SYM;
t.ptr=INDEX;
return t;
}
else {
t.id=SYM;
t.ptr=POINT;
ungetNextChar();
return t;
}
LS5:
while(c[]=getNextChar(),c[]!=EOF&&c[]!='}') {
if(c[]=='\n'||c[]=='\r')num_of_lines++;
}
if(c[]=='}') {
c[]=getNextChar();
goto LS0;
} else {
handle_error(COMMENT_ERROR,"");
}
LS6:
strcat(str,c);
c[]=getNextChar();
if(c[]=='=') {
t.id=SYM;
t.ptr=ASSI;
return t;
} else {
handle_error(SYM_ERROR,"符号为 \':\'");
}
LS7:
while(c[]=getNextChar(),c[]!=EOF&&c[]!='\'') {
strcat(str,c);
}
if(c[]=='\'') {
t.id=STR;
t.ptr=addSTRTable(str);
return t;
} else {
handle_error(STR_ERROR,"");
}
LS8:
t.id=-;
num_of_lines++;
return t;
LS9:
t.id=SYM;
t.ptr=EOFF;
return t;
LS10:
t.id=-;
return t;
OTHER:
handle_error(NOT_REC_SYMBOL,c);
t.id=-;
return t;
}
void show_token(Token t) {
if(t.id==STR) {
printf("<%d %s %s> \n",t.linenum,"STR",STR_table[t.ptr]);
return ;
}
if(t.id==NUM) {
printf("<%d %s %d> \n",t.linenum,"NUM",NUM_table[t.ptr]);
return ;
}
if(t.id==ID) {
printf("<%d %s %s> \n",t.linenum,"ID",ID_table[t.ptr]);
return ;
}
if(t.id==RES) {
printf("<%d %s %s> \n",t.linenum,"RES",reserved_words[t.ptr]);
return ;
}
if(t.id==SYM) {
printf("<%d %s %s> \n",t.linenum,"SYM",symbol_table[t.ptr-]);
return ;
}
return ;
}
vector<Token>* getTokenlist(const char* filename) {
tokens->clear();
file=fopen(filename,"r");
Token temp;
while(temp=scan(),!(temp.id==SYM&&temp.ptr==EOFF)) {
if(temp.id!=-) {
tokens->push_back(temp);
if(temp.id==RES&&strcmp("end",reserved_words[temp.ptr])==) {
char c;
if(c=getNextChar(),c=='.') {
break;
} else {
ungetNextChar();
}
}
}
}
fclose(file);
return tokens;
}
void show_Token_list() {
int len=tokens->size();
for(int i=; i<len; i++) {
show_token(tokens->at(i));
}
} void write_token(FILE* file,Token t) {
if(t.id==STR) {
fprintf(file,"<%s %s> \n","STR",STR_table[t.ptr]);
return ;
}
if(t.id==NUM) {
fprintf(file,"<%s %d> \n","NUM",NUM_table[t.ptr]);
return ;
}
if(t.id==ID) {
fprintf(file,"<%s %s> \n","ID",ID_table[t.ptr]);
return ;
}
if(t.id==RES) {
fprintf(file,"<%s %s> \n","RES",reserved_words[t.ptr]);
return ;
}
if(t.id==SYM) {
fprintf(file,"<%s %s> \n","SYM",symbol_table[t.ptr-]);
return ;
}
return ;
}
void save_Token_list(const char* filename) {
FILE* f=fopen(filename,"w");
int len=tokens->size();
for(int i=; i<len; i++) {
write_token(f,tokens->at(i));
}
fclose(f);
} /***************************************************************************************/
/***************** 语法分析 *****************/
/***************************************************************************************/ void syntaxError(const char* message) {
if(strcmp(message,"outofrange")==) {
printf("出现越界错误");
printf(" Token_n:%d tokens->size:%d\n",Token_n,tokens->size());
exit(-);
}
printf("行号：%d %s",tokens->at(Token_n).linenum,message);
printf("当前token：");
show_token(tokens->at(Token_n));
exit(-);
}
Node* MatchRES(const char* expected) {
if(Token_n>=(int)tokens->size())syntaxError("outofrange");
int id=tokens->at(Token_n).id,ptr=tokens->at(Token_n).ptr;
if(id==RES&&strcmp(expected,reserved_words[ptr])==) {
Node*t =new Node(expected);
Token_n++;
return t;
}
char* message=new char[];
strcpy(message,"match res error.\nexpect: ");
strcat(message,expected);
strcat(message,"\n");
syntaxError(message);
delete message;
return NULL;
}
Node* MatchNUM() {
if(Token_n>=(int)tokens->size())syntaxError("outofrange");
int id=tokens->at(Token_n).id;
if(id==NUM) {
Node* t= new Node("NUM");
Token_n++;
return t;
}
syntaxError("match num error\n");
return NULL;
}
Node* MatchSTR() {
if(Token_n>=(int)tokens->size())syntaxError("outofrange");
int id=tokens->at(Token_n).id;
if(id==STR) {
Node* t= new Node("STR");
Token_n++;
return t;
}
syntaxError("match str error\n");
return NULL;
}
Node* MatchID() {
if(Token_n>=(int)tokens->size())syntaxError("outofrange");
int id=tokens->at(Token_n).id;
if(id==ID) {
Node* t =new Node("ID");
Token_n++;
return t;
}
syntaxError("match id error\n");
return NULL;
}
Node* MatchSYM(const int expected) {
if(Token_n>=(int)tokens->size())syntaxError("outofrange");
int id=tokens->at(Token_n).id,ptr=tokens->at(Token_n).ptr;
if(id==SYM&&ptr==expected) {
Node* t =new Node(symbol_table[ptr-]);
Token_n++;
return t;
}
char* message=new char[];
strcpy(message,"match symbol error.\nexpect: ");
strcat(message,symbol_table[expected-]);
strcat(message,"\n");
syntaxError(message);
delete message;
return NULL;
}
bool isRES(const char* res) {
if(Token_n>=(int)tokens->size())syntaxError("outofrange");
int id=tokens->at(Token_n).id,ptr=tokens->at(Token_n).ptr;
if(id==RES&&strcmp(reserved_words[ptr],res)==)return true;
return false;
}
bool isSYM(const int res) {
if(Token_n>=(int)tokens->size())syntaxError("outofrange");
int id=tokens->at(Token_n).id,ptr=tokens->at(Token_n).ptr;
if(id==SYM&&ptr==res)return true;
return false;
}
bool isID() {
if(Token_n>=(int)tokens->size())syntaxError("outofrange");
int id=tokens->at(Token_n).id;
if(id==ID)return true;
return false;
}
bool isNUM() {
if(Token_n>=(int)tokens->size())syntaxError("outofrange");
int id=tokens->at(Token_n).id;
if(id==NUM)return true;
return false;
}
bool isSTR() {
if(Token_n>=(int)tokens->size())syntaxError("outofrange");
int id=tokens->at(Token_n).id;
if(id==STR)return true;
return false;
}
Node* Program() {
Node* t=new Node("Program");
add(t->children,ProgramHead());
add(t->children,DeclarePart());
add(t->children,ProgramBody());
return t;
}
Node* ProgramHead() {
Node* t=new Node("ProgramHead");
add(t->children,MatchRES("program"));
add(t->children,MatchID());
return t;
} Node* DeclarePart() {
Node* t=new Node("DeclarePart");
add(t->children,TypeDeclaration());
add(t->children,VarDeclaration());
add(t->children,ProcDeclaration());
return t;
}
Node* TypeDec() {
Node* t=new Node("TypeDec");
add(t->children,MatchRES("type"));
add(t->children,TypeDecList());
return t;
}
Node* TypeDeclaration() {
Node*t=NULL;
if(isRES("type")) {
t=new Node("TypeDeclaration");
add(t->children,TypeDec());
}
return t;
}
Node* TypeDecList() {
Node* t=new Node("TypeDecList");
add(t->children,TypeId());
add(t->children,MatchSYM(EQU));
add(t->children,TypeName());
add(t->children,MatchSYM(SEMI));
add(t->children,TypeDecMore());
return t;
}
Node* TypeDecMore() {
Node*t=NULL;
if(isID()) {
t=new Node("TypeDecMore");
add(t->children,TypeDecList());
}
return t;
}
Node* TypeId() {
Node* t=new Node("TypeId");
add(t->children,MatchID());
return t;
}
Node* TypeName() {
Node* t=new Node("TypeName");
if(isRES("integer")||isRES("char")) {
add(t->children,BaseType());
return t;
}
if(isRES("array")||isRES("record")) {
add(t->children,StructureType());
return t;
}
add(t->children,MatchID());
return t;
}
Node* BaseType() {
Node*t=NULL;
if(isRES("integer")) {
t=new Node("BaseType");
add(t->children,MatchRES("integer"));
return t;
}
if(isRES("char")) {
t=new Node("BaseType");
add(t->children,MatchRES("char"));
return t;
}
syntaxError("not a base type\n");
return t;
}
Node* StructureType() {
Node*t=NULL;
if(isRES("array")) {
t=new Node("StructureType");
add(t->children,ArrayType());
return t;
}
if(isRES("record")) {
t=new Node("StructureType");
add(t->children,RecType());
return t;
}
return t;
}
Node* ArrayType() {
Node* t=new Node("ArrayType");
add(t->children,MatchRES("array"));
add(t->children,MatchSYM(LSQUBRACK));
add(t->children,MatchNUM());
add(t->children,MatchSYM(INDEX));
add(t->children,MatchNUM());
add(t->children,MatchSYM(RSQUBRACK));
add(t->children,MatchRES("of"));
add(t->children,BaseType());
return t;
}
Node* RecType() {
Node* t=new Node("RecType");
add(t->children,MatchRES("record"));
add(t->children,FieldDecList());
add(t->children,MatchRES("end"));
return t;
}
Node* FieldDecList() {
Node*t=NULL;
if(isRES("integer")||isRES("char")) {
t=new Node("FieldDecList");
add(t->children,BaseType());
add(t->children,IdList());
add(t->children,MatchSYM(SEMI));
add(t->children,FieldDecMore());
return t;
}
if(isRES("array")) {
t=new Node("FieldDecList");
add(t->children,ArrayType());
add(t->children,IdList());
add(t->children,MatchSYM(SEMI));
add(t->children,FieldDecMore());
return t;
}
syntaxError("field declare list error\n");
return t;
}
Node* FieldDecMore() {
Node*t=NULL;
if(isRES("integer")||isRES("char")||isRES("array")) {
t=new Node("FieldDecMore");
add(t->children,FieldDecList());
}
return t;
}
Node* IdList() {
Node* t=new Node("IdList");
add(t->children,MatchID());
add(t->children,IdMore());
return t;
}
Node* IdMore() {
Node*t=NULL;
if(isSYM(COM)) {
t=new Node("IdMore");
add(t->children,MatchSYM(COM));
add(t->children,IdList());
}
return t;
}
Node* VarDec() {
Node* t=new Node("VarDec");
add(t->children,MatchRES("var"));
add(t->children,VarDecList());
return t;
}
Node* VarDeclaration() {
Node*t=NULL;
if(isRES("var")) {
t=new Node("VarDeclaration");
add(t->children,VarDec());
}
return t;
}
Node* VarDecList() {
Node* t=new Node("VarDecList");
add(t->children,TypeName());
add(t->children,VarIdList());
add(t->children,MatchSYM(SEMI));
add(t->children,VarDecMore());
return t;
}
Node* VarDecMore() {
Node*t=NULL;
if(isRES("integer")||isRES("char")||isRES("array")||isRES("record")||isID()) {
t=new Node("VarDecMore");
add(t->children,VarDecList());
}
return t;
}
Node* VarIdList() {
Node* t=new Node("VarIdList");
add(t->children,MatchID());
add(t->children,VarIdMore());
return t;
}
Node* VarIdMore() {
Node*t=NULL;
if(isSYM(COM)) {
t=new Node("VarIdMore");
add(t->children,MatchSYM(COM));
add(t->children,VarIdList());
}
return t;
}
Node* ProcDec() {
Node* t=new Node("ProcDec");
add(t->children,MatchRES("procedure"));
add(t->children,MatchID());
add(t->children,MatchSYM(LBRACK));
add(t->children,ParamList());
add(t->children,MatchSYM(RBRACK));
add(t->children,MatchSYM(SEMI));
add(t->children,DeclarePart());
add(t->children,ProcBody());
add(t->children,ProcDeclaration());
return t;
}
Node* ProcDeclaration() {
Node*t=NULL;
if(isRES("procedure")) {
t=new Node("ProcDeclaration");
add(t->children,ProcDec());
}
return t;
}
Node* ParamList() {
Node*t=NULL;
if(isRES("integer")||isRES("char")||isRES("array")||isRES("record")||isID()||isRES("var")) {
t=new Node("ParamList");
add(t->children,ParamDecList());
}
return t;
}
Node* ParamDecList() {
Node* t=new Node("ParamDecList");
add(t->children,Param());
add(t->children,ParamMore());
return t;
}
Node* ParamMore() {
Node*t=NULL;
if(isSYM(SEMI)) {
t=new Node("ParamMore");
add(t->children,MatchSYM(SEMI));
add(t->children,ParamDecList());
}
return t;
}
Node* Param() {
Node*t=NULL;
if(isRES("integer")||isRES("char")||isRES("array")||isRES("record")||isID()) {
t=new Node("Param");
add(t->children,TypeName());
add(t->children,FormList());
return t;
}
if(isRES("var")) {
t=new Node("Param");
add(t->children,MatchRES("var"));
add(t->children,TypeName());
add(t->children,FormList());
return t;
}
syntaxError("param error\n");
return t;
}
Node* FormList() {
Node* t=new Node("FormList");
add(t->children,MatchID());
add(t->children,FidMore());
return t;
}
Node* FidMore() {
Node*t=NULL;
if(isSYM(COM)) {
t=new Node("FidMore");
add(t->children,MatchSYM(COM));
add(t->children,FormList());
}
return t;
}
Node* ProcDecPart() {
Node* t=new Node("ProcDecPart");
add(t->children,DeclarePart());
return t;
}
Node* ProcBody() {
Node* t=new Node("ProcBody");
add(t->children,ProgramBody());
return t;
}
Node* ProgramBody() {
Node* t=new Node("ProgramBody");
add(t->children,MatchRES("begin"));
add(t->children,StmList());
add(t->children,MatchRES("end"));
return t;
}
Node* StmList() {
Node* t=new Node("StmList");
add(t->children,Stm());
add(t->children,StmMore());
return t;
}
Node* StmMore() {
Node*t=NULL;
if(isSYM(SEMI)) {
t=new Node("StmMore");
add(t->children,MatchSYM(SEMI));
add(t->children,StmList());
}
return t;
}
Node* Stm() {
Node* t=new Node("Stm");
if(isRES("if")) {
add(t->children,ConditionalStm());
return t;
}
if(isRES("while")) {
add(t->children,LoopStm());
return t;
}
if(isRES("read")) {
add(t->children,InputStm());
return t;
}
if(isRES("write")) {
add(t->children,OutputStm());
return t;
}
if(isRES("return")) {
add(t->children,ReturnStm());
return t;
}
if(isID()) {
add(t->children,MatchID());
add(t->children,AssCall());
return t;
}
delete t;
return NULL;
}
Node* AssCall() {
Node*t=NULL;
if(isSYM(LSQUBRACK)||isSYM(POINT)||isSYM(ASSI)) {
t=new Node("AssCall");
add(t->children,AssignmentRest());
return t;
}
if(isSYM(LBRACK)) {
t=new Node("AssCall");
add(t->children,CallStmRest());
return t;
}
syntaxError("ass call error\n");
return t;
}
Node* AssignmentRest() {
Node* t=new Node("AssignmentRest");
if(isSYM(LSQUBRACK)||isSYM(POINT)) {
add(t->children,VariMore());
}
add(t->children,MatchSYM(ASSI));
add(t->children,Exp());
return t;
}
Node* ConditionalStm() {
Node* t=new Node("ConditionalStm");
add(t->children,MatchRES("if"));
add(t->children,Exp());
if(isSYM(LT))add(t->children,MatchSYM(LT));
else if(isSYM(EQU))add(t->children,MatchSYM(EQU));
else syntaxError("condition error\n");
add(t->children,Exp());
add(t->children,MatchRES("then"));
add(t->children,StmList());
add(t->children,MatchRES("else"));
add(t->children,StmList());
add(t->children,MatchRES("fi"));
return t;
}
Node* LoopStm() {
Node* t=new Node("LoopStm");
add(t->children,MatchRES("while"));
add(t->children,Exp());
if(isSYM(LT))add(t->children,MatchSYM(LT));
else if(isSYM(EQU))add(t->children,MatchSYM(EQU));
else syntaxError("condition error\n");
add(t->children,Exp());
add(t->children,MatchRES("do"));
add(t->children,StmList());
add(t->children,MatchRES("endwh"));
return t;
}
Node* InputStm() {
Node* t=new Node("InputStm");
add(t->children,MatchRES("read"));
add(t->children,MatchSYM(LBRACK));
add(t->children,MatchID());
add(t->children,MatchSYM(RBRACK));
return t;
}
Node* OutputStm() {
Node* t=new Node("OutputStm");
add(t->children,MatchRES("write"));
add(t->children,MatchSYM(LBRACK));
add(t->children,Exp());
add(t->children,MatchSYM(RBRACK));
return t;
}
Node* ReturnStm() {
Node* t=new Node("ReturnStm");
add(t->children,MatchRES("return"));
return t;
}
Node* CallStmRest() {
Node* t=new Node("CallStmRest");
add(t->children,MatchSYM(LBRACK));
add(t->children,ActParamList());
add(t->children,MatchSYM(RBRACK));
return t;
}
Node* ActParamList() {
Node*t=NULL;
if(isSYM(LBRACK)||isNUM()||isID()) {
t=new Node("ActParamList");
add(t->children,Exp());
add(t->children,ActParamMore());
}
return t;
}
Node* ActParamMore() {
Node*t=NULL;
if(isSYM(COM)) {
t=new Node("ActParamMore");
add(t->children,MatchSYM(COM));
add(t->children,ActParamList());
}
return t;
}
Node* Exp() {
Node* t=new Node("Exp");
add(t->children,Term());
add(t->children,OtherTerm());
return t;
}
Node* OtherTerm() {
Node*t=NULL;
if(isSYM(PLUS)||isSYM(SUB)) {
t=new Node("OtherTerm");
add(t->children,AddOp());
add(t->children,Exp());
}
return t;
}
Node* Term() {
Node* t=new Node("Term");
add(t->children,Factor());
add(t->children,OtherFactor());
return t;
}
Node* OtherFactor() {
Node*t=NULL;
if(isSYM(MUL)||isSYM(DIV)) {
t=new Node("OtherFactor");
add(t->children,MultOp());
add(t->children,Term());
}
return t;
}
Node* Factor() {
Node* t=new Node("Factor");
if(isNUM()) {
add(t->children,MatchNUM());
return t;
}
if(isSTR()) {
add(t->children,MatchSTR());
return t;
}
if(isSYM(LBRACK)) {
add(t->children,MatchSYM(LBRACK));
add(t->children,Exp());
add(t->children,MatchSYM(RBRACK));
return t;
}
if(isID()) {
add(t->children,Variable());
return t;
}
delete t;
syntaxError("factor error\n");
return NULL;
}
Node* Variable() {
Node* t=new Node("Variable");
add(t->children,MatchID());
add(t->children,VariMore());
return t;
}
Node* VariMore() {
Node*t=NULL;
if(isSYM(LSQUBRACK)) {
t=new Node("VariMore");
add(t->children,MatchSYM(LSQUBRACK));
add(t->children,Exp());
add(t->children,MatchSYM(RSQUBRACK));
}
if(isSYM(POINT)) {
t=new Node("VariMore");
add(t->children,MatchSYM(POINT));
add(t->children,FieldVar());
}
return t;
}
Node* FieldVar() {
Node* t=new Node("FieldVar");
add(t->children,MatchID());
add(t->children,FieldVarMore());
return t;
}
Node* FieldVarMore() {
Node*t=NULL;
if(isSYM(LSQUBRACK)) {
t=new Node("FieldVarMore");
add(t->children,MatchSYM(LSQUBRACK));
add(t->children,Exp());
add(t->children,MatchSYM(RSQUBRACK));
}
return t;
}
Node* CmpOp() {
Node*t=NULL;
if(isSYM(LT)) {
t=new Node("CmpOp");
add(t->children,MatchSYM(LT));
return t;
}
if(isSYM(EQU)) {
t=new Node("CmpOp");
add(t->children,MatchSYM(EQU));
return t;
}
syntaxError("cmpop error\n");
return t;
}
Node* AddOp() {
Node*t=NULL;
if(isSYM(PLUS)) {
t=new Node("AddOp");
add(t->children,MatchSYM(PLUS));
return t;
}
if(isSYM(SUB)) {
t=new Node("AddOp");
add(t->children,MatchSYM(SUB));
return t;
}
syntaxError("cmpop error\n");
return t;
}
Node* MultOp() {
Node*t=NULL;
if(isSYM(MUL)) {
t=new Node("MultOp");
add(t->children,MatchSYM(MUL));
return t;
}
if(isSYM(DIV)) {
t=new Node("MultOp");
add(t->children,MatchSYM(DIV));
return t;
}
syntaxError("cmpop error\n");
return t;
}
Node* Parse() {
num_of_lines=;
Node* root=Program();
return root;
}
void show_tree(Node* root,int depth,vector<int>* v,bool islast) {
if(root==NULL)return ;
printf("\n");
for(int i=; i<depth; i++) {
if(v->at(i)==)printf(" │");
else printf(" ");
}
if(islast) {
printf(" └─%s",root->desc);
v->at(depth)=;
} else printf(" ├─%s",root->desc);
if(depth+==(int)v->size())v->push_back();
v->at(depth+)=;
int len=root->children.size();
for(int i=; i<len; i++) {
if(i==len-)show_tree(root->children.at(i),depth+,v,true);
else show_tree(root->children.at(i),depth+,v,false);
}
} int main() {
tokens=new vector<Token>();
getTokenlist("cs1.txt");
save_Token_list("tokens.txt");
//打印显示
printf("TOKENS:\n\n");
show_Token_list();
printf("\n\n\n\n语法树:\n\n");
vector<int>* v=new vector<int>();
v->push_back();
show_tree(Parse(),,v,true);
return ;
}
cs1.txt
{冒泡排序}
{输入m,表示要排序的数的个数；接着输入m个整数；
输出从小到大排序后的结果}
program p
var integer i,j,num;
array[..] of integer a;
procedure q(integer num);
var integer i,j,k;
integer t;
begin
i:='lklklk';
j:=;
while i < num do
j:=num-i+;
k:=;
while k<j do
if a[k+] < a[k]
then t:=a[k];
a[k]:=a[k+];
a[k+]:=t
else t:=
fi;
k:=k+
endwh;
i:=i+
endwh
end
begin
read(num);
i:=;
while i<(num+) do
read(j);
a[i]:=j;
i:=i+
endwh;
q(num);
i:=;
while i<(num+) do
write(a[i]);
i:=i+
endwh
end.
END
代码写于大三下6月份，编译原理课程设计
随笔写于2016.7.13