📄 语法分析器.cpp
字号:
return symtable[j].token;
case 12:
ch=nextchar();
if(ch>='0'&&ch<='9') state=13;
else state=fail();
break;
case 13:
ch=nextchar();
if(ch>='0'&&ch<='9') state=13;
else if (ch=='.') state=14;
else if (ch=='E') state=16;
else state=fail();
break;
case 14:
ch=nextchar();
if(ch>='0'&&ch<='9') state=15;
else {
cout<<"line"<<lineno<<":\terror"<<endl;
retract();
lexeme_beginning=forward;
return ERROR;
}
break;
case 15:
ch=nextchar();
if(ch>='0'&&ch<='9') state=15;
else if(ch=='E') state=16;
else state=fail();
break;
case 16:
ch=nextchar();
if(ch=='+'||ch=='-') state=17;
else if(ch>='0'&&ch<='9') state=18;
else state=fail();
break;
case 17:
ch=nextchar();
if(ch>='0'&&ch<='9') state=18;
else state=fail();
break;
case 18:
ch=nextchar();
if(ch>='0'&&ch<='9') state=18;
else state=19;
break;
case 19:
retract();
i=0;
while (lexeme_beginning!=forward) {
if(lexeme_beginning==1024) lexeme_beginning++;
else if(lexeme_beginning==2049) lexeme_beginning=0;
else lexbuf[i++]=file_buf[lexeme_beginning++];
}
lexbuf[i]='\0';
if(!(j=search(lexbuf))) {
lexical_value=insert(lexbuf,NUM);
if(lexical_value==0) return LY_EOF;
}
else
lexical_value=j;
lexeme_beginning=forward;
return NUM;
case 20:
ch=nextchar();
if(ch>='0'&&ch<='9') state=21;
else state=fail();
break;
case 21:
ch=nextchar();
if(ch>='0'&&ch<='9') state=21;
else if(ch=='.') state=22;
else state=fail();
break;
case 22:
ch=nextchar();
if(ch>='0'&&ch<='9') state=23;
else {
cout<<"line"<<lineno<<":\terror"<<endl;
retract();
lexeme_beginning=forward;
return ERROR;
}
break;
case 23:
ch=nextchar();
if(ch>='0'&&ch<='9') state=23;
else state=24;
break;
case 24:
retract();
i=0;
while (lexeme_beginning!=forward) {
if(lexeme_beginning==1024) lexeme_beginning++;
else if(lexeme_beginning==2049) lexeme_beginning=0;
else lexbuf[i++]=file_buf[lexeme_beginning++];
}
lexbuf[i]='\0';
if(!(j=search(lexbuf))) {
lexical_value=insert(lexbuf,NUM);
if(lexical_value==0) return LY_EOF;
}
else
lexical_value=j;
lexeme_beginning=forward;
return NUM;
case 25:
ch=nextchar();
if(ch>='0'&&ch<='9') state=26;
else state=fail();
break;
case 26:
ch=nextchar();
if(ch>='0'&&ch<='9') state=26;
else state=27;
break;
case 27:
retract();
i=0;
while (lexeme_beginning!=forward) {
if(lexeme_beginning==1024) lexeme_beginning++;
else if(lexeme_beginning==2049) lexeme_beginning=0;
else lexbuf[i++]=file_buf[lexeme_beginning++];
}
lexbuf[i]='\0';
if(!(j=search(lexbuf))) {
lexical_value=insert(lexbuf,NUM);
if(lexeme_beginning==0) return LY_EOF;
}
else
lexical_value=j;
lexeme_beginning=forward;
return NUM;
case 40:
ch=nextchar();
if(ch=='/') state=41;
else if(ch==34) state=48;
else if(ch==39) state=50;
else state=fail();
break;
case 41:
ch=nextchar();
if(ch=='*') state=43;
else if(ch=='/') state=42;
else state=44;
break;
case 42:
ch=nextchar();
if(ch==LY_EOF) return LY_EOF;
else if(ch=='\n') { state=47; lineno++;}
else state=42;
break;
case 43:
ch=nextchar();
if(ch==LY_EOF) return LY_EOF;
else if(ch=='*') state=45;
else state=43;
break;
case 44:
retract();
if(!search("/")) {
lexical_value=insert("/",'/');
if(lexical_value==0) return LY_EOF;
}
lexeme_beginning=forward;
return '/';
case 45:
ch=nextchar();
if(ch==LY_EOF) return LY_EOF;
else if(ch=='/') state=46;
else if(ch=='\n') {lineno++; state=43;}
else state=43;
break;
case 46:
lexeme_beginning=forward;
return NOTE;
case 47:
lexeme_beginning=forward;
return NOTE;
case 48:
ch=nextchar();
if(ch==LY_EOF) return LY_EOF;
else if(ch==34) state=49;
else state=48;
break;
case 49:
lexeme_beginning=forward;
return NOTE;
case 50:
ch=nextchar();
if(ch==LY_EOF) return LY_EOF;
else if(ch==39) state=52;
else if(ch==92) state=54;
else state=51;
break;
case 51:
ch=nextchar();
if(ch==LY_EOF) return LY_EOF;
else if(ch==39) state=52;
else state=53;
break;
case 52:
lexeme_beginning=forward;
return NOTE;
case 53:
retract();
lexeme_beginning=forward;
cout<<"line"<<lineno<<":\terror"<<endl;
return ERROR;
case 54:
ch=nextchar();
if(ch==LY_EOF) return LY_EOF;
else state=51;
break;
default:
ch=nextchar();
lexbuf[0]=ch;
lexbuf[1]='\0';
if(!search(lexbuf)) {
lexical_value=insert(lexbuf,ch);
if(lexical_value==0) return LY_EOF;
}
lexeme_beginning=forward;
return ch;
}
}
}
double expparse();
int compare(int Vt1,int Vt2);
int Switch(int Vt);
int parse(){
int a;
int b,temp;
state=0;
start=0;
a=lexan();
if(a==LY_EOF) return a;
if(a>=310&&a<=313){
state=0;
start=0;
b=lexan();
while(1){
if(b!=ID) {
cout<<"line"<<lineno<<":\t语法错误：定义不完整"<<endl;
while(b!=59&&b!=LY_EOF) {
state=0;
start=0;
b=lexan();
}
return b;
}
else{
if(symtable[lexical_value].type!=0)
cout<<"line"<<lineno<<":\t语法错误：重复定义了同一个变量"<<endl;
else
symtable[lexical_value].type=a;
temp=lexical_value;
state=0;
start=0;
b=lexan();
if(b==59) return b;
if(b==EL) {
state=0;
start=0;
b=lexan();
if(b!=ID&&b!=NUM){
cout<<"line"<<lineno<<":\t语法错误：表达式不完整"<<endl;
while(b!=59&&b!=LY_EOF) {
state=0;
start=0;
b=lexan();
}
return b;
}
else{
symtable[temp].value=symtable[lexical_value].value;
}
state=0;
start=0;
b=lexan();
if(b==59) return b;
if(b!=',') {
cout<<"line"<<lineno<<":\t语法错误：本程序暂不能处理"<<endl;
while(b!=59&&b!=LY_EOF) {
state=0;
start=0;
b=lexan();
}
return b;
}
}
else if(b!=','){
cout<<"line"<<lineno<<":\t语法错误：定义语句有错（可能是缺少；）"<<endl;
while(b!=59&&b!=LY_EOF) {
state=0;
start=0;
b=lexan();
}
return b;
}
state=0;
start=0;
b=lexan();
}
}
}
else if(a==ID){
if(symtable[lexical_value].type==0)
cout<<"line"<<lineno<<":\t语法错误：该变量还没有定义"<<endl;
temp=lexical_value;
state=0;
start=0;
a=lexan();
if(a==EL) {
symtable[temp].value=expparse();
return a;
}
else{
cout<<"line"<<lineno<<":\t语法错误： 本程序暂不能处理"<<endl;
while(a!=59&&a!=LY_EOF) {
state=0;
start=0;
a=lexan();
}
return a;
}
}
else if(a==NOTE){
return a ;
}
else{
cout<<"line"<<lineno<<":\t语法错误： 本程序暂不能处理"<<endl;
while(a!=59&&a!=LY_EOF) {
state=0;
start=0;
⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -