www.pudn.com > yufafenxiqi.rar > c--.l

%{ 
#include  
#include  
#include  
#include 	 
#include  "y.tab.h" 
#define HASHLEN 1024 
int nline = 1; 
 
struct id_entry { 
	char * id; 
	struct id_entry *next; /* next entry on hash chain */ 
}; 
 
struct id_entry * id_hash_table[HASHLEN]; 
 
int hash(char * name)  
{ 
  int h = *name++; 
  while (*name) h = h << 4 + *name++; 
  return h; 
} 
 
char * insert_id(char *name) 
{ int h = hash(name) & (HASHLEN-1); 
  struct id_entry *p=id_hash_table[h]; 
  while (p && (strcmp(p->id, name) != 0)) p = p->next; 
  if (p) return p->id; 
  p = (struct id_entry *)malloc(sizeof *p); 
  p->id = (char *)malloc(strlen(name)+1); 
  strcpy(p->id, name); 
  p->next = id_hash_table[h]; 
  id_hash_table[h] = p; /* 新名字在表头 */ 
  return p->id; 
}   
 
%} 
 
/*正规定义*/ 
delim      [ \t] 
ws         {delim}+ 
leter      [A-Za-z]                                         
digit      [0-9] 
id         {leter}({leter}|{digit})*   
number     {digit}+(\.{digit}+)?(E[+\-]?{digit}+)?           
comment    (\#[^\n]*)|(\/\*(((\*)*[^\*\/]+(\/)*)*|(\*)*|(\/)*)\*\/)|(\/\/[^\n]*) 
sentence   \"(.)*\" 
chartype   (\'([^\n]|\n)\')|\'\' 
special    [\@\~\\\$\`]     
%% 
"\n"          { nline++;} 
{comment}  {/*对预处理和注释部分没有动作和返回值*/} 
{ws}       {/*对空白串没有动作和返回值*/} 
{number}   { yylval._ident = insert_id(yytext); return NUM;} 
"__stdcall" {return STDCALL;} 
{chartype}  { yylval._op=yytext[0]; return CHARATER;} 
{sentence}  { yylval._ident=yytext; return STRING ;} 
"__cdecl"   {return CDECL;} 
"if"   {return IF;} 
"int"   {return INT;} 
"void"   {return VOID;} 
"char"   {return CHAR;} 
"else"   {return ELSE;} 
"while"   {return WHILE;} 
"return"   {return RETURN;} 
{id}       { yylval._ident = insert_id(yytext); return ID;} 
"<="       {return LE;} 
">="       {return GE;} 
"<"        {return LT;} 
">"        {return GT;} 
"!="       {return NE;} 
"=="       {return EQ;} 
[+-]	   {yylval._op = yytext[0]; return ADDOP;} 
.          { return yytext[0]; } 
%% 
 
error(char *m) 
{ 
     fprintf(stderr,"%s\n",m); 
     exit(1);         /*非正常终止*/ 
} 
 
int yywrap(){return 1;}