+ // Generate an error message.
+ private String yysyntax_error (int yystate, int tok)
+ {]b4_error_verbose_if([[
+ if (yyErrorVerbose)
+ {
+ /* 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 tok) 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. (However, yychar is currently out
+ of scope during semantic actions.)
+ - 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 (tok != yyempty_)
+ {
+ /* FIXME: This method of building the message is not compatible
+ with internationalization. */
+ StringBuffer res =
+ new StringBuffer ("syntax error, unexpected ");
+ res.append (yytnamerr_ (yytname_[tok]));
+ 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_;
+ int count = 0;
+ for (int x = yyxbegin; x < yyxend; ++x)
+ if (yycheck_[x + yyn] == x && x != yyterror_
+ && !yy_table_value_is_error_ (yytable_[x + yyn]))
+ ++count;
+ if (count < 5)
+ {
+ count = 0;
+ for (int x = yyxbegin; x < yyxend; ++x)
+ if (yycheck_[x + yyn] == x && x != yyterror_
+ && !yy_table_value_is_error_ (yytable_[x + yyn]))
+ {
+ res.append (count++ == 0 ? ", expecting " : " or ");
+ res.append (yytnamerr_ (yytname_[x]));
+ }
+ }
+ }
+ return res.toString ();
+ }
+ }
+]])[
+ return "syntax error";
+ }
projects / bison.git / blobdiff