RE2C(1)                                                   RE2C(1)NNAAMMEE       re2c - convert regular expressions to C/C++SSYYNNOOPPSSIISS       rree22cc [--eessbb] _n_a_m_eDDEESSCCRRIIPPTTIIOONN       rree22cc  is a preprocessor that generates C-based recognizers       from regular expressions.  The input to rree22cc  consists  of       C/C++ source interleaved with comments of the form //**!!rree22cc       ... **// which contain scanner specifications.  In the  out-       put  these comments are replaced with code that, when exe-       cuted, will find the next input  token  and  then  execute       some user-supplied token-specific code.       For example, given the following code          #define NULL            ((char*) 0)          char *scan(char *p){          char *q;          #define YYCTYPE         char          #define YYCURSOR        p          #define YYLIMIT         p          #define YYMARKER        q          #define YYFILL(n)          /*!re2c                  [0-9]+          {return YYCURSOR;}                  [\000-\377]     {return NULL;}          */          }       rree22cc will generate          /* Generated by re2c on Sat Apr 16 11:40:58 1994 */          #line 1 "simple.re"          #define NULL            ((char*) 0)          char *scan(char *p){          char *q;          #define YYCTYPE         char          #define YYCURSOR        p          #define YYLIMIT         p          #define YYMARKER        q          #define YYFILL(n)          {                  YYCTYPE yych;                  unsigned int yyaccept;                  goto yy0;          yy1:    ++YYCURSOR;          yy0:                  if((YYLIMIT - YYCURSOR) < 2) YYFILL(2);                  yych = *YYCURSOR;                  if(yych <= '/') goto yy4;Version 0.5                8 April 1994                         1RE2C(1)                                                   RE2C(1)                  if(yych >= ':') goto yy4;          yy2:    yych = *++YYCURSOR;                  goto yy7;          yy3:          #line 10                  {return YYCURSOR;}          yy4:    yych = *++YYCURSOR;          yy5:          #line 11                  {return NULL;}          yy6:    ++YYCURSOR;                  if(YYLIMIT == YYCURSOR) YYFILL(1);                  yych = *YYCURSOR;          yy7:    if(yych <= '/') goto yy3;                  if(yych <= '9') goto yy6;                  goto yy3;          }          #line 12          }OOPPTTIIOONNSS       rree22cc provides the following options:       --ee     Cross-compile  from  an ASCII platform to an EBCDIC              one.       --ss     Generate nested iiffs for some sswwiittcchhes.   Many  com-              pilers need this assist to generate better code.       --bb     Implies --ss.  Use bit vectors as well in the attempt              to coax better code out of the compiler.  Most use-              ful  for  specifications  with more than a few key-              words (e.g. for most programming languages).IINNTTEERRFFAACCEE CCOODDEE       Unlike other scanner generators, rree22cc  does  not  generate       complete  scanners:  the  user  must supply some interface       code.  In particular, the user must define  the  following       macros:       YYYYCCHHAARR Type used to hold an input symbol.  Usually cchhaarr or              uunnssiiggnneedd cchhaarr.       YYYYCCUURRSSOORR              _l-expression of type **YYYYCCHHAARR  that  points  to  the              current  input symbol.  The generated code advances              YYYYCCUURRSSOORR as symbols are matched.  On entry,  YYYYCCUURR--              SSOORR  is  assumed to point to the first character of              the current token.  On exit, YYYYCCUURRSSOORR will point to              the first character of the following token.Version 0.5                8 April 1994                         2RE2C(1)                                                   RE2C(1)       YYLLIIMMIITT Expression  of  type  **YYYYCCHHAARR that marks the end of              the buffer (YYLLIIMMIITT[[--11]] is the last character in the              buffer).   The  generated  code repeatedly compares              YYYYCCUURRSSOORR to YYLLIIMMIITT to  determine  when  the  buffer              needs (re)filling.       YYYYMMAARRKKEERR              _l-expression  of  type **YYYYCCHHAARR.  The generated code              saves backtracking information in YYYYMMAARRKKEERR.       YYYYFFIILLLL((_n))              The generated code "calls" YYYYFFIILLLL when  the  buffer              needs  (re)filling:   at least _n additional charac-              ters should  be  provided.   YYYYFFIILLLL  should  adjust              YYYYCCUURRSSOORR,  YYYYLLIIMMIITT  and  YYYYMMAARRKKEERR  as needed.  Note              that for typical programming languages  _n  will  be              the length of the longest keyword plus one.SSCCAANNNNEERR SSPPEECCIIFFIICCAATTIIOONNSS       Each  scanner specification consists of a set of _r_u_l_e_s and       name definitions.  Rules consist of a  regular  expression       along  with  a  block of C/C++ code that is to be executed       when the associated regular expression is  matched.   Name       definitions  are  of  the  form  ``_n_a_m_e  == _r_e_g_u_l_a_r _e_x_p_r_e_s_-       _s_i_o_n;;''.SSUUMMMMAARRYY OOFF RREE22CC RREEGGUULLAARR EEXXPPRREESSSSIIOONNSS       ""ffoooo""  the literal string ffoooo.   ANSI-C  escape  sequences              can be used.       [[xxyyzz]]  a  "character  class";  in  this  case, the regular              expression matches either an 'xx', a 'yy', or a  'zz'.       [[aabbjj--ooZZ]]              a  "character class" with a range in it; matches an              'aa', a 'bb', any letter from 'jj' through 'oo',  or  a              'ZZ'.       _r\\_s    match any _r which isn't an _s. _r and _s must be regu-              lar expressions which can be expressed as character              classes.       _r**     zero or more _r's, where _r is any regular expression       _r++     one or more _r's       _r??     zero or one _r's (that is, "an optional _r")       name   the expansion of the "name" definition (see above)       ((_r))    an _r; parentheses are used to  override  precedence              (see below)Version 0.5                8 April 1994                         3RE2C(1)                                                   RE2C(1)       _r_s     an _r followed by an _s ("concatenation")       _r||_s    either an _r or an _s       _r//_s    an  _r  but only if it is followed by an _s. The s is              not part of the matched text. This type of  regular              expression is called "trailing context".       The regular expressions listed above are grouped according       to precedence, from highest precedence at the top to  low-       est  at  the  bottom.   Those  grouped together have equal       precedence.AA LLAARRGGEERR EEXXAAMMPPLLEE          #include <stdlib.h>          #include <stdio.h>          #include <fcntl.h>          #include <string.h>          #define ADDEQ   257          #define ANDAND  258          #define ANDEQ   259          #define ARRAY   260          #define ASM     261          #define AUTO    262          #define BREAK   263          #define CASE    264          #define CHAR    265          #define CONST   266          #define CONTINUE        267          #define DECR    268          #define DEFAULT 269          #define DEREF   270          #define DIVEQ   271          #define DO      272          #define DOUBLE  273          #define ELLIPSIS        274          #define ELSE    275          #define ENUM    276          #define EQL     277          #define EXTERN  278          #define FCON    279          #define FLOAT   280          #define FOR     281          #define FUNCTION        282          #define GEQ     283          #define GOTO    284          #define ICON    285          #define ID      286          #define IF      287          #define INCR    288          #define INT     289          #define LEQ     290Version 0.5                8 April 1994                         4RE2C(1)                                                   RE2C(1)          #define LONG    291          #define LSHIFT  292          #define LSHIFTEQ        293          #define MODEQ   294          #define MULEQ   295          #define NEQ     296          #define OREQ    297          #define OROR    298          #define POINTER 299          #define REGISTER        300          #define RETURN  301          #define RSHIFT  302          #define RSHIFTEQ        303          #define SCON    304          #define SHORT   305          #define SIGNED  306          #define SIZEOF  307          #define STATIC  308          #define STRUCT  309          #define SUBEQ   310          #define SWITCH  311          #define TYPEDEF 312          #define UNION   313          #define UNSIGNED        314          #define VOID    315          #define VOLATILE        316          #define WHILE   317          #define XOREQ   318          #define EOI     319          typedef unsigned int uint;          typedef unsigned char uchar;          #define BSIZE   8192          #define YYCTYPE         uchar          #define YYCURSOR        cursor          #define YYLIMIT         s->lim          #define YYMARKER        s->ptr          #define YYFILL(n)       {cursor = fill(s, cursor);}          #define RET(i)  {s->cur = cursor; return i;}          typedef struct Scanner {              int                 fd;              uchar               *bot, *tok, *ptr, *cur, *pos, *lim, *top, *eof;              uint                line;          } Scanner;          uchar *fill(Scanner *s, uchar *cursor){              if(!s->eof){                  uint cnt = s->tok - s->bot;                  if(cnt){                      memcpy(s->bot, s->tok, s->lim - s->tok);Version 0.5                8 April 1994                         5