/********************************************
scan.c
copyright 1991, Michael D. Brennan

This is a source file for mawk, an implementation of
the AWK programming language.

Mawk is distributed without warranty under the terms of
the GNU General Public License, version 2, 1991.
********************************************/


/* $Log: scan.c,v $
 * Revision 1.8  1996/07/28 21:47:05  mike
 * gnuish patch
 *
 * Revision 1.7  1995/06/18  19:42:24  mike
 * Remove some redundant declarations and add some prototypes
 *
 * Revision 1.6  1995/06/10  16:57:52  mike
 * silently exit(0) if no program
 * always add a '\n' on eof in scan_fillbuff()
 *
 * Revision 1.5  1995/06/06  00:18:33  mike
 * change mawk_exit(1) to mawk_exit(2)
 *
 * Revision 1.4  1994/09/23  00:20:04  mike
 * minor bug fix: handle \ in eat_nl()
 *
 * Revision 1.3  1993/07/17  00:45:21  mike
 * indent
 *
 * Revision 1.2	 1993/07/04  12:52:09  mike
 * start on autoconfig changes
 *
 * Revision 1.1.1.1  1993/07/03	 18:58:20  mike
 * move source to cvs
 *
 * Revision 5.6	 1993/02/13  21:57:33  mike
 * merge patch3
 *
 * Revision 5.5	 1993/01/01  21:30:48  mike
 * split new_STRING() into new_STRING and new_STRING0
 *
 * Revision 5.4.1.1  1993/01/15	 03:33:50  mike
 * patch3: safer double to int conversion
 *
 * Revision 5.4	 1992/11/29  18:57:50  mike
 * field expressions convert to long so 16 bit and 32 bit
 * systems behave the same
 *
 * Revision 5.3	 1992/07/08  15:43:41  brennan
 * patch2: length returns.  I am a wimp
 *
 * Revision 5.2	 1992/02/21  14:16:53  brennan
 * fix:	 getline <=
 *
 * Revision 5.1	 91/12/05  07:56:27  brennan
 * 1.1 pre-release
 *
*/


#include  "mawk.h"
#include  "scan.h"
#include  "memory.h"
#include  "field.h"
#include  "init.h"
#include  "fin.h"
#include  "repl.h"
#include  "code.h"

#ifndef	  NO_FCNTL_H
#include  <fcntl.h>
#endif

#include  "files.h"


/* static functions */
static void PROTO(scan_fillbuff, (void)) ;
static void PROTO(scan_open, (void)) ;
static int PROTO(slow_next, (void)) ;
static void PROTO(eat_comment, (void)) ;
static void PROTO(eat_semi_colon, (void)) ;
static double PROTO(collect_decimal, (int, int *)) ;
static int PROTO(collect_string, (void)) ;
static int PROTO(collect_RE, (void)) ;


/*-----------------------------
  program file management
 *----------------------------*/

char *pfile_name ;
STRING *program_string ;
PFILE *pfile_list ;
static unsigned char *buffer ;
static unsigned char *buffp ;
 /* unsigned so it works with 8 bit chars */
static int program_fd ;
static int eof_flag ;

void
scan_init(cmdline_program)
   char *cmdline_program ;
{
   if (cmdline_program)
   {
      program_fd = -1 ;		 /* command line program */
      program_string = new_STRING0(strlen(cmdline_program) + 1) ;
      strcpy(program_string->str, cmdline_program) ;
      /* simulate file termination */
      program_string->str[program_string->len - 1] = '\n' ;
      buffp = (unsigned char *) program_string->str ;
      eof_flag = 1 ;
   }
   else	 /* program from file[s] */
   {
      scan_open() ;
      buffp = buffer = (unsigned char *) zmalloc(BUFFSZ + 1) ;
      scan_fillbuff() ;
   }

#ifdef OS2  /* OS/2 "extproc" is similar to #! */
   if (strnicmp(buffp, "extproc ", 8) == 0)
     eat_comment();
#endif
   eat_nl() ;			 /* scan to first token */
   if (next() == 0)
   {
      /* no program */
      mawk_exit(0) ;
   }

   un_next() ;

}

static void
scan_open()			/* open pfile_name */
{
   if (pfile_name[0] == '-' && pfile_name[1] == 0)
   {
      program_fd = 0 ;
   }
   else if ((program_fd = open(pfile_name, O_RDONLY, 0)) == -1)
   {
      errmsg(errno, "cannot open %s", pfile_name) ;
      mawk_exit(2) ;
   }
}

void
scan_cleanup()
{
   if (program_fd >= 0)	 zfree(buffer, BUFFSZ + 1) ;
   else	 free_STRING(program_string) ;

   if (program_fd > 0)	close(program_fd) ;

   /* redefine SPACE as [ \t\n] */

   scan_code['\n'] = posix_space_flag && rs_shadow.type != SEP_MLR
      ? SC_UNEXPECTED : SC_SPACE ;
   scan_code['\f'] = SC_UNEXPECTED ;	 /*value doesn't matter */
   scan_code['\013'] = SC_UNEXPECTED ;	 /* \v not space */
   scan_code['\r'] = SC_UNEXPECTED ;
}

/*--------------------------------
  global variables shared by yyparse() and yylex()
  and used for error messages too
 *-------------------------------*/

int current_token = -1 ;
unsigned token_lineno ;
unsigned compile_error_count ;
int NR_flag ;			 /* are we tracking NR */
int paren_cnt ;
int brace_cnt ;
int print_flag ;		 /* changes meaning of '>' */
int getline_flag ;		 /* changes meaning of '<' */


/*----------------------------------------
 file reading functions
 next() and un_next(c) are macros in scan.h

 *---------------------*/

static unsigned lineno = 1 ;


static void
scan_fillbuff()
{
   unsigned r ;

   r = fillbuff(program_fd, (char *) buffer, BUFFSZ) ;
   if (r < BUFFSZ)
   {
      eof_flag = 1 ;
      /* make sure eof is terminated */
      buffer[r] = '\n' ;
      buffer[r + 1] = 0 ;
   }
}

/* read one character -- slowly */
static int
slow_next()
{

   while (*buffp == 0)
   {
      if (!eof_flag)
      {
	 buffp = buffer ;
	 scan_fillbuff() ;
      }
      else if (pfile_list /* open another program file */ )
      {
	 PFILE *q ;

	 if (program_fd > 0)  close(program_fd) ;
	 eof_flag = 0 ;
	 pfile_name = pfile_list->fname ;
	 q = pfile_list ;
	 pfile_list = pfile_list->link ;
	 ZFREE(q) ;
	 scan_open() ;
	 token_lineno = lineno = 1 ;
      }
      else  break /* real eof */ ;
   }

   return *buffp++ ;		 /* note can un_next() , eof which is zero */
}

static void
eat_comment()
{
   register int c ;

   while ((c = next()) != '\n' && scan_code[c]) ;
   un_next() ;
}

/* this is how we handle extra semi-colons that are
   now allowed to separate pattern-action blocks

   A proof that they are useless clutter to the language:
   we throw them away
*/

static void
eat_semi_colon()
/* eat one semi-colon on the current line */
{
   register int c ;

   while (scan_code[c = next()] == SC_SPACE) ;
   if (c != ';')  un_next() ;
}

void
eat_nl()			/* eat all space including newlines */
{
   while (1)
      switch (scan_code[next()])
      {
	 case SC_COMMENT:
	    eat_comment() ;
	    break ;

	 case SC_NL:
	    lineno++ ;
	    /* fall thru  */

	 case SC_SPACE:
	    break ;

	 case SC_ESCAPE:
	    /* bug fix - surprised anyone did this,
	       a csh user with backslash dyslexia.(Not a joke)
	    */
	    {
	       unsigned c ;

	       while (scan_code[c = next()] == SC_SPACE) ;
	       if (c == '\n')
		  token_lineno = ++lineno ;
	       else if (c == 0)  
	       {
		  un_next() ;
		  return ;
	       }
	       else /* error */
	       {
		  un_next() ;
		  /* can't un_next() twice so deal with it */
		  yylval.ival = '\\' ;
		  unexpected_char() ;
		  if( ++compile_error_count == MAX_COMPILE_ERRORS )
		     mawk_exit(2) ;
		  return ;
	       }
	    }
	    break ;
	     
	 default:
	    un_next() ;
	    return ;
      }
}

int
yylex()
{
   register int c ;

   token_lineno = lineno ;

reswitch:

   switch (scan_code[c = next()])
   {
      case 0:
	 ct_ret(EOF) ;

      case SC_SPACE:
	 goto reswitch ;

      case SC_COMMENT:
	 eat_comment() ;
	 goto reswitch ;

      case SC_NL:
	 lineno++ ;
	 eat_nl() ;
	 ct_ret(NL) ;

      case SC_ESCAPE:
	 while (scan_code[c = next()] == SC_SPACE) ;
	 if (c == '\n')
	 {
	    token_lineno = ++lineno ;
	    goto reswitch ;
	 }

	 if (c == 0)  ct_ret(EOF) ;
	 un_next() ;
	 yylval.ival = '\\' ;
	 ct_ret(UNEXPECTED) ;


      case SC_SEMI_COLON:
	 eat_nl() ;
	 ct_ret(SEMI_COLON) ;

      case SC_LBRACE:
	 eat_nl() ;
	 brace_cnt++ ;
	 ct_ret(LBRACE) ;

      case SC_PLUS:
	 switch (next())
	 {
	    case '+':
	       yylval.ival = '+' ;
	       string_buff[0] =
		  string_buff[1] = '+' ;
	       string_buff[2] = 0 ;
	       ct_ret(INC_or_DEC) ;

	    case '=':
	       ct_ret(ADD_ASG) ;

	    default:
	       un_next() ;
	       ct_ret(PLUS) ;
	 }

      case SC_MINUS:
	 switch (next())
	 {
	    case '-':
	       yylval.ival = '-' ;
	       string_buff[0] =
		  string_buff[1] = '-' ;
	       string_buff[2] = 0 ;
	       ct_ret(INC_or_DEC) ;

	    case '=':
	       ct_ret(SUB_ASG) ;

	    default:
	       un_next() ;
	       ct_ret(MINUS) ;
	 }

      case SC_COMMA:
	 eat_nl() ;
	 ct_ret(COMMA) ;

      case SC_MUL:
	 test1_ret('=', MUL_ASG, MUL) ;

      case SC_DIV:
	 {
	    static int can_precede_div[] =
	    {DOUBLE, STRING_, RPAREN, ID, D_ID, RE, RBOX, FIELD,
	     GETLINE, INC_or_DEC, -1} ;

	    int *p = can_precede_div ;

	    do
	    {
	       if (*p == current_token)
	       {
		  if (*p != INC_or_DEC)	{ test1_ret('=', DIV_ASG, DIV) ; }

		  if (next() == '=')
		  {
		     un_next() ;
		     ct_ret(collect_RE()) ;
		  }
	       }
	    }
	    while (*++p != -1) ;

	    ct_ret(collect_RE()) ;
	 }

      case SC_MOD:
	 test1_ret('=', MOD_ASG, MOD) ;

      case SC_POW:
	 test1_ret('=', POW_ASG, POW) ;

      case SC_LPAREN:
	 paren_cnt++ ;
	 ct_ret(LPAREN) ;

      case SC_RPAREN:
	 if (--paren_cnt < 0)
	 {
	    compile_error("extra ')'") ;
	    paren_cnt = 0 ;
	    goto reswitch ;
	 }

	 ct_ret(RPAREN) ;

      case SC_LBOX:
	 ct_ret(LBOX) ;

      case SC_RBOX:
	 ct_ret(RBOX) ;

      case SC_MATCH:
	 string_buff[0] = '~' ;
	 string_buff[0] = 0 ;
	 yylval.ival = 1 ;
	 ct_ret(MATCH) ;

      case SC_EQUAL:
	 test1_ret('=', EQ, ASSIGN) ;

      case SC_NOT:		/* !  */
	 if ((c = next()) == '~')
	 {
	    string_buff[0] = '!' ;
	    string_buff[1] = '~' ;
	    string_buff[2] = 0 ;
	    yylval.ival = 0 ;
	    ct_ret(MATCH) ;
	 }
	 else if (c == '=')  ct_ret(NEQ) ;

	 un_next() ;
	 ct_ret(NOT) ;


      case SC_LT:		/* '<' */
	 if (next() == '=')  ct_ret(LTE) ;
	 else  un_next() ;

	 if (getline_flag)
	 {
	    getline_flag = 0 ;
	    ct_ret(IO_IN) ;
	 }
	 else  ct_ret(LT) ;

      case SC_GT:		/* '>' */
	 if (print_flag && paren_cnt == 0)
	 {
	    print_flag = 0 ;
	    /* there are 3 types of IO_OUT
	       -- build the error string in string_buff */
	    string_buff[0] = '>' ;
	    if (next() == '>')
	    {
	       yylval.ival = F_APPEND ;
	       string_buff[1] = '>' ;
	       string_buff[2] = 0 ;
	    }
	    else
	    {
	       un_next() ;
	       yylval.ival = F_TRUNC ;
	       string_buff[1] = 0 ;
	    }
	    return current_token = IO_OUT ;
	 }

	 test1_ret('=', GTE, GT) ;

      case SC_OR:
	 if (next() == '|')
	 {
	    eat_nl() ;
	    ct_ret(OR) ;
	 }
	 else
	 {
	    un_next() ;

	    if (print_flag && paren_cnt == 0)
	    {
	       print_flag = 0 ;
	       yylval.ival = PIPE_OUT ;
	       string_buff[0] = '|' ;
	       string_buff[1] = 0 ;
	       ct_ret(IO_OUT) ;
	    }
	    else  ct_ret(PIPE) ;
	 }

      case SC_AND:
	 if (next() == '&')
	 {
	    eat_nl() ;
	    ct_ret(AND) ;
	 }
	 else
	 {
	    un_next() ;
	    yylval.ival = '&' ;
	    ct_ret(UNEXPECTED) ;
	 }

      case SC_QMARK:
	 ct_ret(QMARK) ;

      case SC_COLON:
	 ct_ret(COLON) ;

      case SC_RBRACE:
	 if (--brace_cnt < 0)
	 {
	    compile_error("extra '}'") ;
	    eat_semi_colon() ;
	    brace_cnt = 0 ;
	    goto reswitch ;
	 }

	 if ((c = current_token) == NL || c == SEMI_COLON
	     || c == SC_FAKE_SEMI_COLON || c == RBRACE)
	 {
	    /* if the brace_cnt is zero , we've completed
	       a pattern action block. If the user insists
	       on adding a semi-colon on the same line
	       we will eat it.	Note what we do below:
	       physical law -- conservation of semi-colons */

	    if (brace_cnt == 0)	 eat_semi_colon() ;
	    eat_nl() ;
	    ct_ret(RBRACE) ;
	 }

	 /* supply missing semi-colon to statement that
	     precedes a '}' */
	 brace_cnt++ ;
	 un_next() ;
	 current_token = SC_FAKE_SEMI_COLON ;
	 return SEMI_COLON ;

      case SC_DIGIT:
      case SC_DOT:
	 {
	    double d;
	    int flag ;
	    static double double_zero = 0.0 ;
	    static double double_one = 1.0 ;

	    if ((d = collect_decimal(c, &flag)) == 0.0)
	    {
	       if (flag)  ct_ret(flag) ;
	       else  yylval.ptr = (PTR) & double_zero ;
	    }
	    else if (d == 1.0)
	    {
	       yylval.ptr = (PTR) & double_one ;
	    }
	    else
	    {
	       yylval.ptr = (PTR) ZMALLOC(double) ;
	       *(double *) yylval.ptr = d ;
	    }
	    ct_ret(DOUBLE) ;
	 }

      case SC_DOLLAR:		/* '$' */
	 {
	    double d;
	    int flag ;

	    while (scan_code[c = next()] == SC_SPACE) ;
	    if (scan_code[c] != SC_DIGIT &&
		scan_code[c] != SC_DOT)
	    {
	       un_next() ;
	       ct_ret(DOLLAR) ;
	    }

	    /* compute field address at compile time */
	    if ((d = collect_decimal(c, &flag)) == 0.0)
	    {
	       if (flag)  ct_ret(flag) ; /* an error */
	       else  yylval.cp = &field[0] ;
	    }
	    else
	    {
	       if (d > MAX_FIELD)
	       {
		  compile_error(
		     "$%g exceeds maximum field(%d)", d, MAX_FIELD) ;
		  d = MAX_FIELD ;
	       }
	       yylval.cp = field_ptr((int) d) ;
	    }

	    ct_ret(FIELD) ;
	 }

      case SC_DQUOTE:
	 return current_token = collect_string() ;

      case SC_IDCHAR:		/* collect an identifier */
	 {
	    unsigned char *p =
	    (unsigned char *) string_buff + 1 ;
	    SYMTAB *stp ;

	    string_buff[0] = c ;

	    while (
		     (c = scan_code[*p++ = next()]) == SC_IDCHAR ||
		     c == SC_DIGIT) ;

	    un_next() ;
	    *--p = 0 ;

	    switch ((stp = find(string_buff))->type)
	    {
	       case ST_NONE:
		  /* check for function call before defined */
		  if (next() == '(')
		  {
		     stp->type = ST_FUNCT ;
		     stp->stval.fbp = (FBLOCK *)
			zmalloc(sizeof(FBLOCK)) ;
		     stp->stval.fbp->name = stp->name ;
		     stp->stval.fbp->code = (INST *) 0 ;
		     yylval.fbp = stp->stval.fbp ;
		     current_token = FUNCT_ID ;
		  }
		  else
		  {
		     yylval.stp = stp ;
		     current_token =
			current_token == DOLLAR ? D_ID : ID ;
		  }
		  un_next() ;
		  break ;

	       case ST_NR:
		  NR_flag = 1 ;
		  stp->type = ST_VAR ;
		  /* fall thru */

	       case ST_VAR:
	       case ST_ARRAY:
	       case ST_LOCAL_NONE:
	       case ST_LOCAL_VAR:
	       case ST_LOCAL_ARRAY:

		  yylval.stp = stp ;
		  current_token =
		     current_token == DOLLAR ? D_ID : ID ;
		  break ;

	       case ST_ENV:
		  stp->type = ST_ARRAY ;
		  stp->stval.array = new_ARRAY() ;
		  load_environ(stp->stval.array) ;
		  yylval.stp = stp ;
		  current_token =
		     current_token == DOLLAR ? D_ID : ID ;
		  break ;

	       case ST_FUNCT:
		  yylval.fbp = stp->stval.fbp ;
		  current_token = FUNCT_ID ;
		  break ;

	       case ST_KEYWORD:
		  current_token = stp->stval.kw ;
		  break ;

	       case ST_BUILTIN:
		  yylval.bip = stp->stval.bip ;
		  current_token = BUILTIN ;
		  break ;

	       case ST_LENGTH:

		  yylval.bip = stp->stval.bip ;

		  /* check for length alone, this is an ugly
			 hack */
		  while (scan_code[c = next()] == SC_SPACE) ;
		  un_next() ;

		  current_token = c == '(' ? BUILTIN : LENGTH ;
		  break ;

	       case ST_FIELD:
		  yylval.cp = stp->stval.cp ;
		  current_token = FIELD ;
		  break ;

	       default:
		  bozo("find returned bad st type") ;
	    }
	    return current_token ;
	 }


      case SC_UNEXPECTED:
	 yylval.ival = c & 0xff ;
	 ct_ret(UNEXPECTED) ;
   }
   return 0 ;			 /* never get here make lint happy */
}

/* collect a decimal constant in temp_buff.
   Return the value and error conditions by reference */

static double
collect_decimal(c, flag)
   int c ;
   int *flag ;
{
   register unsigned char *p = (unsigned char *) string_buff + 1 ;
   unsigned char *endp ;
   double d;

   *flag = 0 ;
   string_buff[0] = c ;

   if (c == '.')
   {
      if (scan_code[*p++ = next()] != SC_DIGIT)
      {
	 *flag = UNEXPECTED ;
	 yylval.ival = '.' ;
	 return 0.0 ;
      }
   }
   else
   {
      while (scan_code[*p++ = next()] == SC_DIGIT) ;
      if (p[-1] != '.')
      {
	 un_next() ;
	 p-- ;
      }
   }
   /* get rest of digits after decimal point */
   while (scan_code[*p++ = next()] == SC_DIGIT) ;

   /* check for exponent */
   if (p[-1] != 'e' && p[-1] != 'E')
   {
      un_next() ;
      *--p = 0 ;
   }
   else	 /* get the exponent */
   {
      if (scan_code[*p = next()] != SC_DIGIT &&
	  *p != '-' && *p != '+')
      {
	 *++p = 0 ;
	 *flag = BAD_DECIMAL ;
	 return 0.0 ;
      }
      else  /* get the rest of the exponent */
      {
	 p++ ;
	 while (scan_code[*p++ = next()] == SC_DIGIT) ;
	 un_next() ;
	 *--p = 0 ;
      }
   }

   errno = 0 ;			 /* check for overflow/underflow */
   d = strtod(string_buff, (char **) &endp) ;

#ifndef	 STRTOD_UNDERFLOW_ON_ZERO_BUG
   if (errno)  compile_error("%s : decimal %sflow", string_buff,
		    d == 0.0 ? "under" : "over") ;
#else /* ! sun4 bug */
   if (errno && d != 0.0)
      compile_error("%s : decimal overflow", string_buff) ;
#endif

   if (endp < p)
   {
      *flag = BAD_DECIMAL ;
      return 0.0 ;
   }
   return d ;
}

/*----------  process escape characters ---------------*/

static char hex_val['f' - 'A' + 1] =
{
   10, 11, 12, 13, 14, 15, 0, 0,
   0, 0, 0, 0, 0, 0, 0, 0,
   0, 0, 0, 0, 0, 0, 0, 0,
   0, 0, 0, 0, 0, 0, 0, 0,
   10, 11, 12, 13, 14, 15} ;

#define isoctal(x)  ((x)>='0'&&(x)<='7')

#define	 hex_value(x)	hex_val[(x)-'A']

#define ishex(x) (scan_code[x] == SC_DIGIT ||\
		  ('A' <= (x) && (x) <= 'f' && hex_value(x)))

static int PROTO(octal, (char **)) ;
static int PROTO(hex, (char **)) ;

/* process one , two or three octal digits
   moving a pointer forward by reference */
static int
octal(start_p)
   char **start_p ;
{
   register char *p = *start_p ;
   register unsigned x ;

   x = *p++ - '0' ;
   if (isoctal(*p))
   {
      x = (x << 3) + *p++ - '0' ;
      if (isoctal(*p))	x = (x << 3) + *p++ - '0' ;
   }
   *start_p = p ;
   return x & 0xff ;
}

/* process one or two hex digits
   moving a pointer forward by reference */

static int
hex(start_p)
   char **start_p ;
{
   register unsigned char *p = (unsigned char *) *start_p ;
   register unsigned x ;
   unsigned t ;

   if (scan_code[*p] == SC_DIGIT)  x = *p++ - '0' ;
   else	 x = hex_value(*p++) ;

   if (scan_code[*p] == SC_DIGIT)  x = (x << 4) + *p++ - '0' ;
   else if ('A' <= *p && *p <= 'f' && (t = hex_value(*p)))
   {
      x = (x << 4) + t ;
      p++ ;
   }

   *start_p = (char *) p ;
   return x ;
}

#define	 ET_END	    9

static struct
{
   char in, out ;
}
escape_test[ET_END + 1] =
{
  {'n', '\n'},
  {'t', '\t'},
  {'f', '\f'},
  {'b', '\b'},
  {'r', '\r'},
  {'a', '\07'},
  {'v', '\013'},
  {'\\', '\\'},
  {'\"', '\"'},
  {0, 0}
} ;


/* process the escape characters in a string, in place . */

char *
rm_escape(s)
   char *s ;
{
   register char *p, *q ;
   char *t ;
   int i ;

   q = p = s ;

   while (*p)
   {
      if (*p == '\\')
      {
	 escape_test[ET_END].in = *++p ; /* sentinal */
	 i = 0 ;
	 while (escape_test[i].in != *p)  i++ ;

	 if (i != ET_END)	/* in table */
	 {
	    p++ ;
	    *q++ = escape_test[i].out ;
	 }
	 else if (isoctal(*p))
	 {
	    t = p ;
	    *q++ = octal(&t) ;
	    p = t ;
	 }
	 else if (*p == 'x' && ishex(*(unsigned char *) (p + 1)))
	 {
	    t = p + 1 ;
	    *q++ = hex(&t) ;
	    p = t ;
	 }
	 else if (*p == 0)	/* can only happen with command line assign */
	    *q++ = '\\' ;
	 else  /* not an escape sequence */
	 {
	    *q++ = '\\' ;
	    *q++ = *p++ ;
	 }
      }
      else  *q++ = *p++ ;
   }

   *q = 0 ;
   return s ;
}

static int
collect_string()
{
   register unsigned char *p = (unsigned char *) string_buff ;
   int c ;
   int e_flag = 0 ;		 /* on if have an escape char */

   while (1)
      switch (scan_code[*p++ = next()])
      {
	 case SC_DQUOTE:	/* done */
	    *--p = 0 ;
	    goto out ;

	 case SC_NL:
	    p[-1] = 0 ;
	    /* fall thru */

	 case 0:		/* unterminated string */
	    compile_error(
			    "runaway string constant \"%.10s ...",
			    string_buff, token_lineno) ;
	    mawk_exit(2) ;

	 case SC_ESCAPE:
	    if ((c = next()) == '\n')
	    {
	       p-- ;
	       lineno++ ;
	    }
	    else if (c == 0)  un_next() ;
	    else
	    {
	       *p++ = c ;
	       e_flag = 1 ;
	    }

	    break ;

	 default:
	    break ;
      }

out:
   yylval.ptr = (PTR) new_STRING(
				   e_flag ? rm_escape(string_buff)
				   : string_buff) ;
   return STRING_ ;
}


static int
collect_RE()
{
   register unsigned char *p = (unsigned char *) string_buff ;
   int c ;
   STRING *sval ;

   while (1)
      switch (scan_code[*p++ = next()])
      {
	 case SC_DIV:		/* done */
	    *--p = 0 ;
	    goto out ;

	 case SC_NL:
	    p[-1] = 0 ;
	    /* fall thru */

	 case 0:		/* unterminated re */
	    compile_error(
			    "runaway regular expression /%.10s ...",
			    string_buff, token_lineno) ;
	    mawk_exit(2) ;

	 case SC_ESCAPE:
	    switch (c = next())
	    {
	       case '/':
		  p[-1] = '/' ;
		  break ;

	       case '\n':
		  p-- ;
		  break ;

	       case 0:
		  un_next() ;
		  break ;

	       default:
		  *p++ = c ;
		  break ;
	    }
	    break ;
      }

out:
   /* now we've got the RE, so compile it */
   sval = new_STRING(string_buff) ;
   yylval.ptr = re_compile(sval) ;
   free_STRING(sval) ;
   return RE ;
}