c-.l

一个编译器的例子,基于c语言,在linux下开发 现在了简单的c语言例子

/*
 *  COMP510-04A  COMPILER
 *  Project for 510  
 *  name:   Yinghao Qin
 *  
 *  username: yq11
 *  ID:   0130348
 *  Date: 16/06/2004
 */

      
%{
#include "stdio.h"
#include "c-.tab.h"
//char yytext[];
char *getmem(char *); 
void count(); 

//int column = 0;
%}

eol            "\n"
linecomment    "//"[^\n]*{eol}
blockcomment   "/*"

digit          [0-9]
letter         [A-Za-z_]
string         \"([^\"])*\"
hex           [a-fA-F0-9]
exponent   [Ee][+-]?{digit}+
integer      {digit}+
float          {digit}+\.{digit}+

identifier     {letter}(_|{letter}|{digit})* 

%%

{linecomment}         { ++currLine;}         
{blockcomment}        { blcomment();}

{string}              { count(); yylval.val = getmem(yytext); return  (STRING);}

"void"               { count(); yylval.val = getmem(yytext);return  (VOID);}
"char"               { count(); yylval.val = getmem(yytext);return  (CHAR);}
"int"                  { count(); yylval.val = getmem(yytext);return  (INT);}
"float"                { count(); yylval.val = getmem(yytext);return  (FLOAT);}
"double"            { count(); yylval.val = getmem(yytext);return  (DOUBLE);}

"if"                    { count(); yylval.val = getmem(yytext);return  (IF);}
"else"                { count(); yylval.val = getmem(yytext);return  (ELSE);}
"break"              { count(); yylval.val = getmem(yytext);return  (BREAK);}
"continue"          { count(); yylval.val = getmem(yytext);return  (CONTINUE);}
"while"               { count(); yylval.val = getmem(yytext);return  (WHILE);}

"return"              { count(); yylval.val = getmem(yytext);return  (RETURN);}
"goto"                { count(); yylval.val = getmem(yytext);return  (GOTO);}
"do"                   { count(); yylval.val = getmem(yytext);return  (DO);}
"switch"              { count(); yylval.val = getmem(yytext);return  (SWITCH);}
"case"                { count(); yylval.val = getmem(yytext);return  (CASE);}
"default"              { count(); yylval.val = getmem(yytext);return  (DEFAULT);}
"for"                    { count(); yylval.val = getmem(yytext);return  (FOR);}
"struct"                { count(); yylval.val = getmem(yytext);return  (STRUCT);}
"println"                { yylval.val = getmem(yytext);return  (PRINTLN);}

{integer}              { count(); yylval.val = getmem(yytext); return  (INT_VAL);}
'(\\.|[^\\'])+'         { count(); yylval.val = getmem(yytext); return  (CHAR_VAL);}
0[xX]{hex}+         { count(); yylval.val = getmem(yytext); return  (HEX_VAL);}
{float}                 { count(); yylval.val = getmem(yytext); return  (FLT_VAL);}
{exponent}         { count(); yylval.val = getmem(yytext); return  (EP_VAL);}

"{"                   { count(); yylval.val = getmem(yytext);return  ('{');}
"}"                   { count(); yylval.val = getmem(yytext);return  ('}');}
"("                   { count(); yylval.val = getmem(yytext);return  ('(');}
")"                   { count(); yylval.val = getmem(yytext);return  (')');}
"["                   { count(); yylval.val = getmem(yytext);return  ('[');}
"]"                   { count(); yylval.val = getmem(yytext);return  (']');}
"&&"                  { count(); yylval.val = getmem(yytext);return  (AND_OP); }
"||"                  { count(); yylval.val = getmem(yytext);return  (OR_OP); }
"<="                  { count(); yylval.val = getmem(yytext);return  (LE_OP); }
">="                  { count(); yylval.val = getmem(yytext);return  (GE_OP); }
"=="                  { count(); yylval.val = getmem(yytext);return  (EQ_OP); }
"!="                  { count(); yylval.val = getmem(yytext);return  (NE_OP); }

">>="               { count(); yylval.val = getmem(yytext);return  (RIGHT_ASSIGN); }
"<<="               { count(); yylval.val = getmem(yytext);return  (LEFT_ASSIGN); }
"+="                 { count(); yylval.val = getmem(yytext);return  (ADD_ASSIGN); }
"-="                  { count(); yylval.val = getmem(yytext);return  (SUB_ASSIGN); }
"*="                  { count(); yylval.val = getmem(yytext);return  (MUL_ASSIGN); }
"/="                  { count(); yylval.val = getmem(yytext);return  (DIV_ASSIGN); }
"%="                { count(); yylval.val = getmem(yytext);return  (MOD_ASSIGN); }
"&="                 { count(); yylval.val = getmem(yytext);return  (AND_ASSIGN); }
"^="                  { count(); yylval.val = getmem(yytext);return  (XOR_ASSIGN); }
"|="                   { count(); yylval.val = getmem(yytext);return  (OR_ASSIGN); }
">>"                  { count(); yylval.val = getmem(yytext);return  (RIGHT_OP); }
"<<"                  { count(); yylval.val = getmem(yytext);return  (LEFT_OP); }
"++"                  { count(); yylval.val = getmem(yytext);return  (INC_OP); }
"--"                   { count(); yylval.val = getmem(yytext);return  (DEC_OP); }
"->"                   { count(); yylval.val = getmem(yytext);return  (PTR_OP); }
"~"                   {count();  yylval.val = getmem(yytext);return  (PRN_OP); }

"&"                   {count();  return  ('&'); }
"!"                   { count(); return  ('!'); }
"="                   { count(); return  ('='); }
"."                   { count(); return  ('.'); }
":"                   { count(); return  (':'); }
";"                   { count(); return (';'); }
"-"                   {count();  return  ('-'); }
"+"                   { count(); return  ('+'); }
"*"                   { count(); return  ('*'); }
"/"                   {count();  return  ('/'); }
"%"                   {count();  return  ('%'); }
"<"                   { count(); return  ('<'); }
">"                   {count();  return  ('>'); }
"^"                   { count(); return  ('^'); }
"?"                   {count();  return  ('?'); }

{identifier}          { count(); yylval.val = getmem(yytext); return  (ID);}
","                   { count(); return  (',');}
\n                    { count(); ++currLine;}
[ \t\v\f]+              {count(); }/* eat up whitespace */

.                     { printf(" Unrecognized character:%s\n", yytext);}

%%

char *getmem(char *s)
{
char *str;
str = (char *)malloc(strlen(s)+1);
strcpy(str,s);
str[strlen(s)]='\0';
return str;
}

void count()
{
        int i;
       
        for (i = 0; yytext[i] != '\0'; i++)
                if (yytext[i] == '\n')
                        column = 0;
                else if (yytext[i] == '\t')
                        column += 8 - (column % 8);
                else
                        column++;
//printf("\n===========%d\n",column);
       // ECHO;
}

int blcomment()
{
int c;
while((c=input())!=0){
if(c=='\n') ++currLine;
if(c=='*'){            // if find * sign, then check the following charactor 
if((c=input())=='/')  // if found / following a *, then comment end 
	break;
else
	unput(c);
}
}
putchar('\n');
return 0;
}