Function compile_arg

extern/btyacc/reader.c:1061–1133

}

static char *compile_arg(char **theptr, char *yyvaltag)
{
char		*p = *theptr;
struct mstring	*c = msnew();
int		i, j, n;
Yshort		*offsets=0, maxoffset;
bucket		**rhs;

    maxoffset = n = 0;
    for (i = nitems - 1; pitem[i]; --i) {
	n++;
	if (pitem[i]->class != ARGUMENT)
	    maxoffset++; }
    if (maxoffset > 0) {
	offsets = NEW2(maxoffset+1, Yshort);
	if (offsets == 0) no_space(); }
    for (j=0, i++; i<nitems; i++)
	if (pitem[i]->class != ARGUMENT)
	    offsets[++j] = i - nitems + 1;
    rhs = pitem + nitems - 1;

    if (yyvaltag)
	msprintf(c, "yyval.%s = ", yyvaltag);
    else
	msprintf(c, "yyval = ");
    while (*p) {
      if (*p == '$') {
	char	*tag = 0;
	if (*++p == '<')
	  if (!(p = parse_id(++p, &tag)) || *p++ != '>')
	    illegal_tag(rescan_lineno, 0, 0);
	if (isdigit(*p) || *p == '-') {
	  int val;
	  if (!(p = parse_int(p, &val)))
	    dollar_error(rescan_lineno, 0, 0);
	  if (val <= 0) i = val - n;
	  else if (val > maxoffset) {
	    dollar_warning(rescan_lineno, val);
	    i = val - maxoffset; 
	  } else {
	    i = offsets[val];
	    if (!tag && !(tag = rhs[i]->tag) && havetags)
	      untyped_rhs(val, rhs[i]->name); 
	  }
	  msprintf(c, "yyvsp[%d]", i);
	  if (tag) msprintf(c, ".%s", tag);
	  else if (havetags)
	    unknown_rhs(val); 
	} else if (isalpha(*p) || *p == '_') {
	  char	*arg;
	  if (!(p = parse_id(p, &arg)))
	    dollar_error(rescan_lineno, 0, 0);
	  for (i=plhs[nrules]->args-1; i>=0; i--)
	    if (arg == plhs[nrules]->argnames[i]) break;
	  if (i<0)
	    error(rescan_lineno, 0, 0, "unknown argument $%s", arg);
	  if (!tag)
	    tag = plhs[nrules]->argtags[i];