# Java skeleton for Bison -*- autoconf -*-
-# Copyright (C) 2007, 2008, 2009 Free Software Foundation, Inc.
+# Copyright (C) 2007-2011 Free Software Foundation, Inc.
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
m4_divert_push(0)dnl
@output(b4_parser_file_name@)@
b4_copyright([Skeleton implementation for Bison LALR(1) parsers in Java],
- [2007, 2008, 2009])
+ [2007-2011])
b4_percent_define_ifdef([package], [package b4_percent_define_get([package]);
])[/* First part of user declarations. */
* printing an error message. */
public static final int YYERROR = 2;
- /**
- * Returned by a Bison action in order to print an error message and start
- * error recovery. Formally deprecated in Bison 2.4.2's NEWS entry, where
- * a plan to phase it out is discussed. */
- public static final int YYFAIL = 3;
-
+ // Internal return codes that are not supported for user semantic
+ // actions.
+ private static final int YYERRLAB = 3;
private static final int YYNEWSTATE = 4;
private static final int YYDEFAULT = 5;
private static final int YYREDUCE = 6;
else if ((yyn = yytable_[yyn]) <= 0)
{
if (yy_table_value_is_error_ (yyn))
- label = YYFAIL;
+ label = YYERRLAB;
else
{
yyn = -yyn;
case YYDEFAULT:
yyn = yydefact_[yystate];
if (yyn == 0)
- label = YYFAIL;
+ label = YYERRLAB;
else
label = YYREDUCE;
break;
/*------------------------------------.
| yyerrlab -- here on detecting error |
`------------------------------------*/
- case YYFAIL:
+ case YYERRLAB:
/* If not already recovering from an error, report this error. */
if (yyerrstatus_ == 0)
{
++yynerrs_;
+ if (yychar == yyempty_)
+ yytoken = yyempty_;
yyerror (]b4_locations_if([yylloc, ])[yysyntax_error (yystate, yytoken));
}
{]b4_error_verbose_if([[
if (yyErrorVerbose)
{
- int yyn = yypact_[yystate];
- if (yypact_ninf_ < yyn && yyn <= yylast_)
+ /* There are many possibilities here to consider:
+ - Assume YYFAIL is not used. It's too flawed to consider.
+ See
+ <http://lists.gnu.org/archive/html/bison-patches/2009-12/msg00024.html>
+ for details. YYERROR is fine as it does not invoke this
+ function.
+ - 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_)
{
- StringBuffer res;
-
- /* 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;
-
// FIXME: This method of building the message is not compatible
// with internationalization.
- res = new StringBuffer ("syntax error, unexpected ");
+ StringBuffer res =
+ new StringBuffer ("syntax error, unexpected ");
res.append (yytnamerr_ (yytname_[tok]));
- if (count < 5)
+ int yyn = yypact_[yystate];
+ if (!yy_pact_value_is_default_ (yyn))
{
- count = 0;
+ /* 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]))
- {
- res.append (count++ == 0 ? ", expecting " : " or ");
- res.append (yytnamerr_ (yytname_[x]));
- }
+ ++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 ();
}
projects / bison.git / blobdiff