c--.l.txt

用yacc写的c编译器

digit [0-9] 
letter [A-Za-z] 
other_char [!-@\[-~] 
id ({letter}|[_])({letter}|{digit}|[_])* 
string {({letter}|{digit}|{other_char})+} 
int_num {digit}+ 

%% 
[ |\t|\n]+ 
"auto"|"double"|"int"|"struct"|"break"|"else"|"long"|"switch"|"case"|"enum"|"register"|"typedef"|"char"|"extern"|"return"|"union"|"const"|"float"|"short"|"unsigned"|"continue"|"for"|"signed"|"void"|"default"|"goto"|"sizeof"|"do"|"if"|"static"|"while"|"main" {Upper(yytext,yyleng);printf("%s,NULL\n",yytext);} 
\"([!-~])*\" {printf("CONST_string,%s\n",yytext);} 
-?{int_num}[.]{int_num}?([E][+|-]?{int_num})? {printf("CONST_real,%s\n",yytext);} 
"0x"?{int_num} {printf("CONST_int,%s\n",yytext);} 
","|";"|"("|")"|"{"|"}"|"["|"]"|"->"|"."|"!"|"~"|"++"|"--"|"*"|"&"|"sizeof"|"/"|"%"|"+"|"-"|">"|"<"|">="|"<="|"=="|"!="|"&"|"^"|"|"|"&"|"||"|"+="|"-="|"*="|"/="|"%="|">>="|"<<="|"&="|"^="|"|="|"=" {printf("%s,NULL\n",yytext);} 
{id} {printf("ID,%s\n",yytext);} 

{digit}({letter})+ {printf("error1:%s\n",yytext);} 

%% 
＃i nclude <ctype.h> 
Upper(char *s,int l) 
{ 
int i; 
for(i=0;i<l;i++) 
{ 
s[i]=toupper(s[i]); 
} 
} 
yywrap() 
{ 
return 1; 
}