/* 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; }
// 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; }