/* Copy into *YYMSG, which is of size *YYMSG_ALLOC, an error message
   about the unexpected token YYTOKEN for the state stack whose top is
   YYSSP.

   Return 0 if *YYMSG was successfully written.  Return 1 if *YYMSG is
   not large enough to hold the message.  In that case, also set
   *YYMSG_ALLOC to the required number of bytes.  Return 2 if the
   required number of bytes is too large to store.  */
static int
yysyntax_error (YYSIZE_T *yymsg_alloc, char **yymsg,
                yytype_int16 *yyssp, int yytoken)
{
  YYSIZE_T yysize0 = yytnamerr (YY_NULLPTR, yytname[yytoken]);
  YYSIZE_T yysize = yysize0;
  enum { YYERROR_VERBOSE_ARGS_MAXIMUM = 5 };
  /* Internationalized format string. */
  const char *yyformat = YY_NULLPTR;
  /* Arguments of yyformat. */
  char const *yyarg[YYERROR_VERBOSE_ARGS_MAXIMUM];
  /* Number of reported tokens (one for the "unexpected", one per
     "expected"). */
  int yycount = 0;

  /* There are many possibilities here to consider:
     - If this state is a consistent state with a default action, then
       the only way this function was invoked is if the default action
       is an error action.  In that case, don't check for expected
       tokens because there are none.
     - The only way there can be no lookahead present (in yychar) is if
       this state is a consistent state with a default action.  Thus,
       detecting the absence of a lookahead is sufficient to determine
       that there is no unexpected or expected token to report.  In that
       case, just report a simple "syntax error".
     - Don't assume there isn't a lookahead just because this state is a
       consistent state with a default action.  There might have been a
       previous inconsistent state, consistent state with a non-default
       action, or user semantic action that manipulated yychar.
     - Of course, the expected token list depends on states to have
       correct lookahead information, and it depends on the parser not
       to perform extra reductions after fetching a lookahead from the
       scanner and before detecting a syntax error.  Thus, state merging
       (from LALR or IELR) and default reductions corrupt the expected
       token list.  However, the list is correct for canonical LR with
       one exception: it will still contain any token that will not be
       accepted due to an error action in a later state.
  */
  if (yytoken != YYEMPTY)
    {
      int yyn = yypact[*yyssp];
      yyarg[yycount++] = yytname[yytoken];
      if (!yypact_value_is_default (yyn))
        {
          /* Start YYX at -YYN if negative to avoid negative indexes in
             YYCHECK.  In other words, skip the first -YYN actions for
             this state because they are default actions.  */
          int yyxbegin = yyn < 0 ? -yyn : 0;
          /* Stay within bounds of both yycheck and yytname.  */
          int yychecklim = YYLAST - yyn + 1;
          int yyxend = yychecklim < YYNTOKENS ? yychecklim : YYNTOKENS;
          int yyx;

          for (yyx = yyxbegin; yyx < yyxend; ++yyx)
            if (yycheck[yyx + yyn] == yyx && yyx != YYTERROR
                && !yytable_value_is_error (yytable[yyx + yyn]))
              {
                if (yycount == YYERROR_VERBOSE_ARGS_MAXIMUM)
                  {
                    yycount = 1;
                    yysize = yysize0;
                    break;
                  }
                yyarg[yycount++] = yytname[yyx];
                {
                  YYSIZE_T yysize1 = yysize + yytnamerr (YY_NULLPTR, yytname[yyx]);
                  if (! (yysize <= yysize1
                         && yysize1 <= YYSTACK_ALLOC_MAXIMUM))
                    return 2;
                  yysize = yysize1;
                }
              }
        }
    }

  switch (yycount)
    {
# define YYCASE_(N, S)                      \
      case N:                               \
        yyformat = S;                       \
      break
      YYCASE_(0, YY_("syntax error"));
      YYCASE_(1, YY_("syntax error, unexpected %s"));
      YYCASE_(2, YY_("syntax error, unexpected %s, expecting %s"));
      YYCASE_(3, YY_("syntax error, unexpected %s, expecting %s or %s"));
      YYCASE_(4, YY_("syntax error, unexpected %s, expecting %s or %s or %s"));
      YYCASE_(5, YY_("syntax error, unexpected %s, expecting %s or %s or %s or %s"));
# undef YYCASE_
    }

  {
    YYSIZE_T yysize1 = yysize + yystrlen (yyformat);
    if (! (yysize <= yysize1 && yysize1 <= YYSTACK_ALLOC_MAXIMUM))
      return 2;
    yysize = yysize1;
  }

  if (*yymsg_alloc < yysize)
    {
      *yymsg_alloc = 2 * yysize;
      if (! (yysize <= *yymsg_alloc
             && *yymsg_alloc <= YYSTACK_ALLOC_MAXIMUM))
        *yymsg_alloc = YYSTACK_ALLOC_MAXIMUM;
      return 1;
    }

  /* Avoid sprintf, as that infringes on the user's name space.
     Don't have undefined behavior even if the translation
     produced a string with the wrong number of "%s"s.  */
  {
    char *yyp = *yymsg;
    int yyi = 0;
    while ((*yyp = *yyformat) != '\0')
      if (*yyp == '%' && yyformat[1] == 's' && yyi < yycount)
        {
          yyp += yytnamerr (yyp, yyarg[yyi++]);
          yyformat += 2;
        }
      else
        {
          yyp++;
          yyformat++;
        }
  }
  return 0;
}
예제 #2
0
  // Generate an error message.
  std::string
  Parser::yysyntax_error_ (state_type yystate, symbol_number_type yytoken) const
  {
    std::string yyres;
    // Number of reported tokens (one for the "unexpected", one per
    // "expected").
    size_t yycount = 0;
    // Its maximum.
    enum { YYERROR_VERBOSE_ARGS_MAXIMUM = 5 };
    // Arguments of yyformat.
    char const *yyarg[YYERROR_VERBOSE_ARGS_MAXIMUM];

    /* There are many possibilities here to consider:
       - If this state is a consistent state with a default action, then
         the only way this function was invoked is if the default action
         is an error action.  In that case, don't check for expected
         tokens because there are none.
       - The only way there can be no lookahead present (in yytoken) is
         if this state is a consistent state with a default action.
         Thus, detecting the absence of a lookahead is sufficient to
         determine that there is no unexpected or expected token to
         report.  In that case, just report a simple "syntax error".
       - Don't assume there isn't a lookahead just because this state is
         a consistent state with a default action.  There might have
         been a previous inconsistent state, consistent state with a
         non-default action, or user semantic action that manipulated
         yyla.  (However, yyla is currently not documented for users.)
       - Of course, the expected token list depends on states to have
         correct lookahead information, and it depends on the parser not
         to perform extra reductions after fetching a lookahead from the
         scanner and before detecting a syntax error.  Thus, state
         merging (from LALR or IELR) and default reductions corrupt the
         expected token list.  However, the list is correct for
         canonical LR with one exception: it will still contain any
         token that will not be accepted due to an error action in a
         later state.
    */
    if (yytoken != yyempty_)
      {
        yyarg[yycount++] = yytname_[yytoken];
        int yyn = yypact_[yystate];
        if (!yy_pact_value_is_default_ (yyn))
          {
            /* Start YYX at -YYN if negative to avoid negative indexes in
               YYCHECK.  In other words, skip the first -YYN actions for
               this state because they are default actions.  */
            int yyxbegin = yyn < 0 ? -yyn : 0;
            // Stay within bounds of both yycheck and yytname.
            int yychecklim = yylast_ - yyn + 1;
            int yyxend = yychecklim < yyntokens_ ? yychecklim : yyntokens_;
            for (int yyx = yyxbegin; yyx < yyxend; ++yyx)
              if (yycheck_[yyx + yyn] == yyx && yyx != yyterror_
                  && !yy_table_value_is_error_ (yytable_[yyx + yyn]))
                {
                  if (yycount == YYERROR_VERBOSE_ARGS_MAXIMUM)
                    {
                      yycount = 1;
                      break;
                    }
                  else
                    yyarg[yycount++] = yytname_[yyx];
                }
          }
      }

    char const* yyformat = YY_NULLPTR;
    switch (yycount)
      {
#define YYCASE_(N, S)                         \
        case N:                               \
          yyformat = S;                       \
        break
        YYCASE_(0, YY_("syntax error"));
        YYCASE_(1, YY_("syntax error, unexpected %s"));
        YYCASE_(2, YY_("syntax error, unexpected %s, expecting %s"));
        YYCASE_(3, YY_("syntax error, unexpected %s, expecting %s or %s"));
        YYCASE_(4, YY_("syntax error, unexpected %s, expecting %s or %s or %s"));
        YYCASE_(5, YY_("syntax error, unexpected %s, expecting %s or %s or %s or %s"));
#undef YYCASE_
      }

    // Argument number.
    size_t yyi = 0;
    for (char const* yyp = yyformat; *yyp; ++yyp)
      if (yyp[0] == '%' && yyp[1] == 's' && yyi < yycount)
        {
          yyres += yytnamerr_ (yyarg[yyi++]);
          ++yyp;
        }
      else
        yyres += *yyp;
    return yyres;
  }