四川大学Cminus语法分析器纯代码

#include<fstream>#include<iostream>#include<string>#include<strstream>using namespace std;#define BUFLEN 256#define MAXLEN 256#define MAXTOKENLEN 40#define MAXCHILDREN 4static int lineno;static int linepos = 0;//读取的字符在lineBuf的位置static int EOF_FLAG = false;static int bufsize = 0;//lineBuf的长度static char lineBuf[BUFLEN];FILE * source;char tokenString[MAXTOKENLEN+1];string output;//输出文件enum TokenType{ENDFILE,ERROR,IF,ELSE,INT,RETURN,VOID,WHILE,ID,NUM,ASSIGN,EQ,LT,PLUS,MINUS,TIMES,OVER,LPAREN,RPAREN,SEMI,LBRACKET,RBRA CKET,LBRACE,RBRACE,COMMA,GT,GEQ,NEQ,LEQ};enum StateType{START,INASSIGN,INCOMMENT,INNUM,INID,DONE,PRECOMMENT,AFTERCOMMENT };struct{char* str;TokenType tok;}ReserverWords[6]= { {"if",IF},{"else",ELSE},{"int",INT},{"return",RETURN},{"void",VOID},{"w hile",WHILE} };void UnGetNextChar(){if (!EOF_FLAG)linepos--;}int GetNextChar(){if(!(linepos<bufsize)){lineno++;if(fgets(lineBuf,BUFLEN-1,source)){bufsize=strlen(lineBuf);linepos=0;return lineBuf[linepos++];}else{EOF_FLAG=true;return EOF;}}else{return lineBuf[linepos++];}}TokenType ReservedLookUp(char * s){int i;for (i = 0; i < 6; i++){if(!strcmp(s,ReserverWords[i].str)){return ReserverWords[i].tok;}}return ID;}TokenType GetToken(){StateType state = START;//初始状态为startbool save;TokenType CurrentToken;int tokenStringIndex=0;string assign="";while(state!=DONE){int c=GetNextChar();save = true;switch (state){case START:if (isdigit(c)){state = INNUM;}else if (isalpha(c)){state = INID;}else if ((c == '<')||(c=='>')||(c=='=')||(c=='!')){state = INASSIGN;assign+=char(c);}else if ((c == ' ') || (c == '\t') || (c == '\n'))save = false;else if (c == '/'){save = false;state = PRECOMMENT;}else{state = DONE;switch (c){case EOF:save = false;CurrentToken = ENDFILE;break;case'+':CurrentToken = PLUS;break;case'-':CurrentToken = MINUS;break;case'*':CurrentToken = TIMES;break;case'(':CurrentToken = LPAREN;break;case')':CurrentToken = RPAREN;break;case';':CurrentToken = SEMI;break;case'[':CurrentToken = LBRACKET;break;case']':CurrentToken = RBRACKET;break;case'{':CurrentToken = LBRACE;break;case'}':CurrentToken = RBRACE;break;case',':CurrentToken = COMMA;break;default:CurrentToken = ERROR;break;}}break;case INCOMMENT:save = false;if (c == EOF){state = DONE;CurrentToken = ENDFILE;}else if (c == '*')state = AFTERCOMMENT;else{state=INCOMMENT;}break;case INASSIGN:if (c == '='){CurrentToken = EQ;state=DONE;}else if(assign=="!"){UnGetNextChar();save = false;CurrentToken = ERROR;state=DONE;}else if(assign=="="){UnGetNextChar();save = false;CurrentToken =ASSIGN ;state=DONE;}else if(assign=="<"){UnGetNextChar();save = false;CurrentToken =LT ;state=DONE;}else{UnGetNextChar();save = false;CurrentToken =GT ;state=DONE;}break;case INNUM:if (!isdigit(c)){UnGetNextChar();save = false;state = DONE;CurrentToken = NUM;}break;case INID:if (!isalpha(c)){UnGetNextChar();save = false;state = DONE;CurrentToken = ID;}break;case PRECOMMENT:if(c=='*'){state=INCOMMENT;save=false;}else{UnGetNextChar();CurrentToken=OVER;state=DONE;}break;case AFTERCOMMENT:save=false;if(c=='/'){state=START;}else if(c=='*'){state=AFTERCOMMENT;}else{state=INCOMMENT;}break;case DONE:default:state = DONE;CurrentToken = ERROR;break;}if((save)&&(tokenStringIndex<=MAXTOKENLEN)){tokenString[tokenStringIndex++]=(char)c;}if(state==DONE){tokenString[tokenStringIndex]='\0';if(CurrentToken==ID){CurrentToken=ReservedLookUp(tokenString);}}}return CurrentToken;}enum NodeKind//节点类型{FuncK,IntK,IdK,ParamsK,ParamK,CompK,ConstK,CallK,ArgsK,VoidK,Var_De clK,Arry_DeclK,Arry_ElemK,AssignK/*,WhileK*/,OpK,Selection_StmtK,Iteration_StmtK,Return_StmtK};struct//节点类型和字符串关系{string str;NodeKind nk;}nodekind[18]= { {"Funck",FuncK},{"IntK",IntK},{"IdK",IdK},{"ParamsK",ParamsK},{"ParamK" ,ParamK},{"CompK",CompK},{"ConstK",ConstK},{"CallK",CallK},{"ArgsK",ArgsK},{"VoidK",VoidK},{"Var_DeclK",Var_DeclK},{"Arry_DeclK",Arry_ DeclK},{"Arry_ElemK",Arry_ElemK},{"AssignK",AssignK},/*{"WhileK",WhileK},*/{"OpK",OpK},{"Selection_StmtK",Selection_StmtK},{"Ite ration_StmtK",Iteration_StmtK},{"Return_StmtK",Return_StmtK}};struct//符号与字符串关系{string str;TokenType tk;}Ope[11]= { {"=",ASSIGN},{"==",EQ},{"<",LT},{"+",PLUS},{"-",MINUS},{"*",TIMES},{"/" ,OVER},{">",GT},{">=",GEQ},{"!=",NEQ},{"<=",LEQ}};string OpeLookUp(TokenType tk)//操作符转换为字符串{int i;for(i=0;i<11;i++){if(tk==Ope[i].tk){return Ope[i].str;}}}string Change(NodeKind nk)//节点类型转换为字符串{int i;for(i=0;i<19;i++){if(nk==nodekind[i].nk){return nodekind[i].str;break;}}}TokenType token;struct TreeNode{struct TreeNode * child[4];struct TreeNode * sibling;int lineno;NodeKind nodekind;union { TokenType op; int val; const char * name;} attr;};TreeNode * declaration_list(void);TreeNode * declaration(void);TreeNode * params(void);TreeNode * param_list(TreeNode * p);TreeNode * param(TreeNode * p);TreeNode * compound_stmt(void);TreeNode * local_declaration(void);TreeNode * statement_list(void);TreeNode * statement(void);TreeNode * expression_stmt(void);TreeNode * selection_stmt(void);TreeNode * iteration_stmt(void);TreeNode * return_stmt(void);TreeNode * expression(void);TreeNode * var(void);TreeNode * simple_expression(TreeNode * p); TreeNode * additive_expression(TreeNode * p); TreeNode * term(TreeNode * p);TreeNode * factor(TreeNode * p);TreeNode * call(TreeNode * p);TreeNode * args(void);char * copyString(char *s){int n;char * t;if (s==NULL){return NULL;}n=strlen(s)+1;t=(char*)malloc(n);if (t==NULL){}else{strcpy(t,s);}return t;}void match(TokenType expected){if(token==expected)token=GetToken();else{cout<<"unexpected token"<<endl;}}TreeNode * newNode(NodeKind kind){TreeNode * t = (TreeNode *) malloc(sizeof(TreeNode));int i;if (t==NULL){;}else {for (i=0;i<4;i++){t->child[i] = NULL;}t->sibling = NULL;t->nodekind = kind;t->lineno = lineno;if (kind==OpK||kind==IntK||kind==IdK){if(kind==IdK)t-> = "";}if(kind==ConstK)t->attr.val = 0;}return t;}TreeNode * declaration_list(void)//declaration_list->declaration_list decla ration | declaration{TreeNode * t = declaration();TreeNode * p =t;while((token!=INT)&&(token!=VOID)&&(token!=ENDFILE)){token = GetToken();if(token==ENDFILE)break;}while(token==INT||token==VOID){TreeNode * q;q = declaration();if (q!=NULL){if (t==NULL){t=p=q;}else{p->sibling=q;p=q;}}}match(ENDFILE);return t;}TreeNode * declaration(void){TreeNode * t = NULL;TreeNode * p = NULL;TreeNode * q = NULL;TreeNode * s = NULL;TreeNode * a = NULL;if (token==INT){p=newNode(IntK);match(INT);}else//(token==VOID){p=newNode(VoidK);match(VOID);}if(p!=NULL&&token==ID){q = newNode(IdK);q-> = copyString(tokenString);match(ID);if (token==LPAREN){t = newNode(FuncK);t->child[0] = p; //p是t子节点t->child[1] = q;match(LPAREN);t->child[2] = params();match(RPAREN);t->child[3] = compound_stmt();}else if (token==LBRACKET){t = newNode(Var_DeclK);a = newNode(Arry_DeclK);t->child[0] = p; //p是t子节点t->child[1] = a;match(LBRACKET);s = newNode(ConstK);s->attr.val = atoi(tokenString);match(NUM);a->child[0]=q;a->child[1]=s;match(RBRACKET);match(SEMI);}else if (token==SEMI){t = newNode(Var_DeclK);t->child[0] = p;t->child[1] = q;match(SEMI);}else{;}}else{;}return t;}TreeNode * params(void)//params_list | void{TreeNode * t = newNode(ParamsK);TreeNode * p = NULL;if (token==VOID){p = newNode(VoidK);match(VOID);if (token==RPAREN){if(t!=NULL)t->child[0] = p;}else//参数列表为(void id,[……]){t->child[0] = param_list(p);}}else//(token==INT){t->child[0] = param_list(p);}return t;}TreeNode * param_list(TreeNode * k)//params_list->params_list,param | param {TreeNode * t = param(k);TreeNode * p = t;k = NULL;//没有要传给param的VoidK，所以将k设为NULLwhile (token==COMMA){TreeNode * q = NULL;match(COMMA);q = param(k);if (q!=NULL){if (t==NULL){t=p=q;}else{p->sibling = q;p = q;}}}return t;}TreeNode * param(TreeNode * k){TreeNode * t = newNode(ParamK);TreeNode * p = NULL;TreeNode * q = NULL;if(k==NULL&&token==VOID){p = newNode(VoidK);match(VOID);}else if(k==NULL&&token==INT){p = newNode(IntK);match(INT);}else if (k!=NULL){p = k;}if(p!=NULL){t->child[0] = p;if (token==ID){q = newNode(IdK);q-> = copyString(tokenString);t->child[1] = q;match(ID);}if (token==LBRACKET&&(t->child[1]!=NULL))//@@@@@@@@@@@@{match(LBRACKET);t->child[2] = newNode(IdK);match(RBRACKET);}else{return t;}}else{;}return t;}TreeNode * compound_stmt(void){TreeNode * t = newNode(CompK);match(LBRACE);t->child[0] = local_declaration();t->child[1] = statement_list();match(RBRACE);return t;}TreeNode * local_declaration(void){TreeNode * t = NULL;TreeNode * q = NULL;TreeNode * p = NULL;while(token==INT || token==VOID){p = newNode(Var_DeclK);if(token==INT){TreeNode * q1 = newNode(IntK);p->child[0] = q1;match(INT);}else if(token==VOID){TreeNode * q1 = newNode(VoidK);p->child[0] = q1;match(INT);}if((p!=NULL)&&(token==ID)){TreeNode * q2 = newNode(IdK);q2-> = copyString(tokenString);p->child[1] = q2;match(ID);if(token==LBRACKET){TreeNode * q3 = newNode(Var_DeclK);p->child[3] = q3;match(LBRACKET);match(RBRACKET);match(SEMI);}else if(token==SEMI){match(SEMI);}else{match(SEMI);}}if(p!=NULL){if(t==NULL)t = q = p;else{q->sibling = p;q = p;}}}return t;}TreeNode * statement_list(void){TreeNode * t = statement();TreeNode * p = t;while (IF==token || LBRACKET==token || ID==token || WHILE==token || RETURN ==token || SEMI==token || LPAREN==token || NUM==token){TreeNode * q;q = statement();if(q!=NULL){if(t==NULL){t = p = q;}else{p->sibling = q;p = q;}}}return t;}TreeNode * statement(void){TreeNode * t = NULL;switch(token){case IF:t = selection_stmt();break;case WHILE:t = iteration_stmt();break;case RETURN:t = return_stmt();break;case LBRACE:t = compound_stmt();break;case ID: case SEMI: case LPAREN: case NUM:t = expression_stmt();break;default:token = GetToken();break;}return t;}TreeNode * selection_stmt(void){TreeNode * t = newNode(Selection_StmtK);match(IF);match(LPAREN);if(t!=NULL){t->child[0] = expression();}match(RPAREN);t->child[1] = statement();if(token==ELSE){match(ELSE);if(t!=NULL){t->child[2] = statement();}}return t;}TreeNode * iteration_stmt(void){TreeNode * t = newNode(Iteration_StmtK);match(WHILE);match(LPAREN);if(t!=NULL){t->child[0] = expression();}match(RPAREN);if(t!=NULL){t->child[1] = statement();}return t;}TreeNode * return_stmt(void){TreeNode * t = newNode(Return_StmtK);match(RETURN);if (token==SEMI){match(SEMI);return t;}else{if(t!=NULL){t->child[0] = expression();}}match(SEMI);return t;}TreeNode * expression_stmt(void){TreeNode * t = NULL;if(token==SEMI){match(SEMI);return t;}else{t = expression();match(SEMI);}return t;}TreeNode * expression(void){TreeNode * t = var();if(t==NULL)//不是以ID开头，只能是simple_expression情况{t = simple_expression(t);}else//以ID开头，可能是赋值语句，或simple_expression中的var和call类型的情况{TreeNode * p = NULL;if(token==ASSIGN)//赋值语句{p = newNode(AssignK);match(ASSIGN);p->child[0] = t;p->child[1] = expression();return p;}else//simple_expression中的var和call类型的情况{t = simple_expression(t);}}return t;}TreeNode * var(void){TreeNode * t = NULL;TreeNode * p = NULL;TreeNode * q = NULL;if(token==ID){p = newNode(IdK);p-> = copyString(tokenString);match(ID);if(token==LBRACKET){match(LBRACKET);q = expression();match(RBRACKET);t = newNode(Arry_ElemK);t->child[0] = p;t->child[1] = q;}else{t = p;}}return t;}TreeNode * simple_expression(TreeNode * k){TreeNode * t = additive_expression(k);k = NULL;if(EQ==token || GT==token || GEQ==token || LT==token || LEQ==token || NEQ==token){TreeNode * q = newNode(OpK);q->attr.op = token;q->child[0] = t;t = q;match(token);t->child[1] = additive_expression(k);return t;}return t;}TreeNode * additive_expression(TreeNode * k){TreeNode * t = term(k);k = NULL;while((token==PLUS)||(token==MINUS)){TreeNode * q = newNode(OpK);q->attr.op = token;q->child[0] = t;match(token);q->child[1] = term(k);t = q;}return t;}TreeNode * term(TreeNode * k){TreeNode * t = factor(k);k = NULL;while((token==TIMES)||(token==OVER)){TreeNode * q = newNode(OpK);q->attr.op = token;q->child[0] = t;t = q;match(token);q->child[1] = factor(k);}return t;}TreeNode * factor(TreeNode * k){TreeNode * t = NULL;if(k!=NULL)//k为上面传下来的已经解析出来的以ID开头的var,可能为call或var{if(token==LPAREN && k->nodekind!=Arry_ElemK) //call{t = call(k);}else{t = k;}}else//没有从上面传下来的var{switch(token){case LPAREN:match(LPAREN);t = expression();match(RPAREN);break;case ID:k = var();if(LPAREN==token && k->nodekind!=Arry_ElemK){t = call(k);}else//如果是连续计算，进入这一步{t=k;}break;case NUM:t = newNode(ConstK);if((t!=NULL)&&(token==NUM)){t->attr.val = atoi(tokenString);}match(NUM);break;default:token = GetToken();break;}}return t;}TreeNode * call(TreeNode * k){TreeNode * t = newNode(CallK);if(k!=NULL)t->child[0] = k;match(LPAREN);if(token==RPAREN){match(RPAREN);return t;}else if(k!=NULL){t->child[1] = args();match(RPAREN);}return t;}TreeNode * args(void){TreeNode * t = newNode(ArgsK);TreeNode * s = NULL;TreeNode * p = NULL;if(token!=RPAREN){s = expression();p = s;while(token==COMMA){TreeNode * q;match(COMMA);q = expression();if(q!=NULL){if(s==NULL){s = p = q;}else{p->sibling = q;p = q;}}}}if(s!=NULL){t->child[0] = s;}return t;}int blank_number=0;void PreOrder(TreeNode* t){string blank=" ";int i;for(i=0;i<blank_number;i++){blank+=" ";}if(t!=NULL){if(t->nodekind==OpK){cout<<blank<<"Op: "<<OpeLookUp(t->attr.op)<<endl;output+=blank+"Op: "+OpeLookUp(t->attr.op)+"\n";}else if(t->nodekind==IdK){cout<<blank<<Change(t->nodekind)<<": "<<t-><<endl;output+=blank+Change(t->nodekind)+": "+t->+"\n";}else if(t->nodekind==ConstK){cout<<blank<<Change(t->nodekind)<<": "<<t->attr.val<<endl;int n=t->attr.val;strstream ss;string s;ss << n;ss >> s;output+=blank+Change(t->nodekind)+": "+s+"\n";}else if(t->nodekind==AssignK){cout<<blank<<"Assign"<<endl;output+=blank+"Assign"+"\n";}else if(t->nodekind==Selection_StmtK){cout<<blank<<"If"<<endl;output+=blank+"If"+"\n";}else if(t->nodekind==Iteration_StmtK){cout<<blank<<"While"<<endl;output+=blank+"While"+"\n";}else if(t->nodekind==Return_StmtK){cout<<blank<<"Return"<<endl;output+=blank+"Return"+"\n";}else{cout<<blank<<Change(t->nodekind)<<endl;output+=blank+Change(t->nodekind)+"\n";}}for(i=0;i<MAXCHILDREN;i++){if(t->child[i]!=NULL){blank_number+=2;PreOrder(t->child[i]);blank_number-=2;}}if(t->sibling!=NULL){PreOrder(t->sibling);}}void parse(void){TreeNode * t;cout<<"Syntax tree:"<<endl;token = GetToken();t = declaration_list();PreOrder(t);}void main(){char* file=(char *)malloc(100);//打开的文件名string result;//输出结果文件名cout<<"请输入文件名.例如：gcd.c-"<<endl;scanf("%s",file);while((source=fopen(file,"r"))==NULL){cout<<"文件名无效,请重新输入"<<endl;scanf("%s",file);}ofstream write;//输出文件result=string(file)+"-Result.txt";write.open(result);write<<"Syntax tree:"<<endl;parse();write<<output;write.close();system("PAUSE");}。