version 3.5.92

* NEWS: Record release date.

.prev-version

@@ -1 +1 @@
-3.5.90
+3.5.91

NEWS

@@ -1,5 +1,13 @@
 GNU Bison NEWS
 
+* Noteworthy changes in release 3.5.92 (2020-05-03) [beta]
+
+  Portability issues.
+
+  More documentation.
+
+  Backward compatibility issues with C++.
+
 * Noteworthy changes in release 3.5.91 (2020-04-29) [stable]
 
 ** New features
@@ -213,8 +221,8 @@ GNU Bison NEWS
 
 *** Examples
 
-  There are now two examples in examples/java: a very simple calculator, and
-  one that tracks locations to provide accurate error messages.
+  There are now examples/java: a very simple calculator, and a more complete
+  one (push-parser, location tracking, and debug traces).
 
   The lexcalc example (a simple example in C based on Flex and Bison) now
   also demonstrates location tracking.
@@ -2545,7 +2553,7 @@ GNU Bison NEWS
   Running "make install-pdf" (or -dvi, -html, -info, and -ps) no longer
   halts in the middle of its course.
 
-* Changes in version 2.5 (2011-05-14):
+* Noteworthy changes in release 2.5 (2011-05-14)
 
 ** Grammar symbol names can now contain non-initial dashes:
 
@@ -2900,7 +2908,7 @@ GNU Bison NEWS
 
   This bug has been fixed.
 
-* Changes in version 2.4.3 (2010-08-05):
+* Noteworthy changes in release 2.4.3 (2010-08-05)
 
 ** Bison now obeys -Werror and --warnings=error for warnings about
    grammar rules that are useless in the parser due to conflicts.
@@ -2920,7 +2928,7 @@ GNU Bison NEWS
 
 ** Minor documentation fixes.
 
-* Changes in version 2.4.2 (2010-03-20):
+* Noteworthy changes in release 2.4.2 (2010-03-20)
 
 ** Some portability problems that resulted in failures and livelocks
    in the test suite on some versions of at least Solaris, AIX, HP-UX,
@@ -3014,7 +3022,7 @@ GNU Bison NEWS
   message translations were not installed although supported by the
   host system.
 
-* Changes in version 2.4.1 (2008-12-11):
+* Noteworthy changes in release 2.4.1 (2008-12-11)
 
 ** In the GLR defines file, unexpanded M4 macros in the yylval and yylloc
    declarations have been fixed.
@@ -3039,7 +3047,7 @@ GNU Bison NEWS
 
 ** A few minor improvements to the Bison manual.
 
-* Changes in version 2.4 (2008-11-02):
+* Noteworthy changes in release 2.4 (2008-11-02)
 
 ** %language is an experimental feature.
 
@@ -3054,7 +3062,7 @@ GNU Bison NEWS
 ** Several bugs in the C++ skeleton and the experimental Java skeleton have been
   fixed.
 
-* Changes in version 2.3b (2008-05-27):
+* Noteworthy changes in release 2.3b (2008-05-27)
 
 ** The quotes around NAME that used to be required in the following directive
   are now deprecated:
@@ -3240,7 +3248,7 @@ GNU Bison NEWS
 ** The nonfunctional --no-parser, -n, and %no-parser options have been
   completely removed from Bison.
 
-* Changes in version 2.3a, 2006-09-13:
+* Noteworthy changes in release 2.3a (2006-09-13)
 
 ** Instead of %union, you can define and use your own union type
   YYSTYPE if your grammar contains at least one <type> tag.
@@ -3354,7 +3362,7 @@ GNU Bison NEWS
   The old spelling still works, but is not documented and may be removed
   in a future release.
 
-* Changes in version 2.3, 2006-06-05:
+* Noteworthy changes in release 2.3 (2006-06-05)
 
 ** GLR grammars should now use "YYRECOVERING ()" instead of "YYRECOVERING",
   for compatibility with LALR(1) grammars.
@@ -3362,7 +3370,7 @@ GNU Bison NEWS
 ** It is now documented that any definition of YYSTYPE or YYLTYPE should
   be to a type name that does not contain parentheses or brackets.
 
-* Changes in version 2.2, 2006-05-19:
+* Noteworthy changes in release 2.2 (2006-05-19)
 
 ** The distribution terms for all Bison-generated parsers now permit
   using the parsers in nonfree programs.  Previously, this permission
@@ -3444,7 +3452,7 @@ GNU Bison NEWS
 
 ** DJGPP support added.
 
-* Changes in version 2.1, 2005-09-16:
+* Noteworthy changes in release 2.1 (2005-09-16)
 
 ** The C++ lalr1.cc skeleton supports %lex-param.
 
@@ -3470,7 +3478,7 @@ GNU Bison NEWS
   print 'syntax error, unexpected number' instead of 'syntax error,
   unexpected "number"'.
 
-* Changes in version 2.0, 2004-12-25:
+* Noteworthy changes in release 2.0 (2004-12-25)
 
 ** Possibly-incompatible changes
 
@@ -3533,7 +3541,7 @@ GNU Bison NEWS
 
   - Semicolons are now allowed before "|" in grammar rules, as POSIX requires.
 
-* Changes in version 1.875, 2003-01-01:
+* Noteworthy changes in release 1.875 (2003-01-01)
 
 ** The documentation license has been upgraded to version 1.2
   of the GNU Free Documentation License.
@@ -3653,7 +3661,7 @@ GNU Bison NEWS
   ago, but nobody noticed until we recently asked someone to try
   building Bison with a K&R C compiler.
 
-* Changes in version 1.75, 2002-10-14:
+* Noteworthy changes in release 1.75 (2002-10-14)
 
 ** Bison should now work on 64-bit hosts.
 
@@ -3684,7 +3692,7 @@ GNU Bison NEWS
   was incorrectly rejected: $1 is defined in the second midrule
   action, and is equal to the $$ of the first midrule action.
 
-* Changes in version 1.50, 2002-10-04:
+* Noteworthy changes in release 1.50 (2002-10-04)
 
 ** GLR parsing
   The declaration
@@ -3828,7 +3836,7 @@ GNU Bison NEWS
 
 ** GNU M4 is now required when using Bison.
 
-* Changes in version 1.35, 2002-03-25:
+* Noteworthy changes in release 1.35 (2002-03-25)
 
 ** C Skeleton
   Some projects use Bison's C parser with C++ compilers, and define
@@ -3843,7 +3851,7 @@ GNU Bison NEWS
   This kludge also addresses some C++ problems when the stack was
   extended.
 
-* Changes in version 1.34, 2002-03-12:
+* Noteworthy changes in release 1.34 (2002-03-12)
 
 ** File name clashes are detected
   $ bison foo.y -d -o foo.x
@@ -3863,7 +3871,7 @@ GNU Bison NEWS
 
 ** Fix test suite portability problems.
 
-* Changes in version 1.33, 2002-02-07:
+* Noteworthy changes in release 1.33 (2002-02-07)
 
 ** Fix C++ issues
   Groff could not be compiled for the definition of size_t was lacking
@@ -3872,7 +3880,7 @@ GNU Bison NEWS
 ** Catch invalid @n
   As is done with $n.
 
-* Changes in version 1.32, 2002-01-23:
+* Noteworthy changes in release 1.32 (2002-01-23)
 
 ** Fix Yacc output file names
 
@@ -3880,7 +3888,7 @@ GNU Bison NEWS
 
 ** Italian, Dutch translations
 
-* Changes in version 1.31, 2002-01-14:
+* Noteworthy changes in release 1.31 (2002-01-14)
 
 ** Many Bug Fixes
 
@@ -3967,7 +3975,7 @@ GNU Bison NEWS
 ** --output
   New, aliasing "--output-file".
 
-* Changes in version 1.30, 2001-10-26:
+* Noteworthy changes in release 1.30 (2001-10-26)
 
 ** "--defines" and "--graph" have now an optional argument which is the
   output file name. "-d" and "-g" do not change; they do not take any
@@ -3978,7 +3986,7 @@ GNU Bison NEWS
 
 ** Portability fixes.
 
-* Changes in version 1.29, 2001-09-07:
+* Noteworthy changes in release 1.29 (2001-09-07)
 
 ** The output file does not define const, as this caused problems when used
   with common autoconfiguration schemes.  If you still use ancient compilers
@@ -4013,7 +4021,7 @@ GNU Bison NEWS
 ** @$
   Automatic location tracking.
 
-* Changes in version 1.28, 1999-07-06:
+* Noteworthy changes in release 1.28 (1999-07-06)
 
 ** Should compile better now with K&R compilers.
 
@@ -4023,12 +4031,12 @@ GNU Bison NEWS
 
 ** There is now a FAQ.
 
-* Changes in version 1.27:
+* Noteworthy changes in release 1.27
 
 ** The make rule which prevented bison.simple from being created on
   some systems has been fixed.
 
-* Changes in version 1.26:
+* Noteworthy changes in release 1.26
 
 ** Bison now uses Automake.
 
@@ -4045,7 +4053,7 @@ GNU Bison NEWS
 ** Generated parsers should now work even on operating systems which do
   not provide alloca().
 
-* Changes in version 1.25, 1995-10-16:
+* Noteworthy changes in release 1.25 (1995-10-16)
 
 ** Errors in the input grammar are not fatal; Bison keeps reading
 the grammar file, and reports all the errors found in it.
@@ -4070,7 +4078,7 @@ the parser engine; a project can now use its own parser engine.
 The actions go into a separate file called NAME.act, in the form of
 a switch statement body.
 
-* Changes in version 1.23:
+* Noteworthy changes in release 1.23
 
 The user can define YYPARSE_PARAM as the name of an argument to be
 passed into yyparse.  The argument should have type void *.  It should
@@ -4079,11 +4087,11 @@ by casting it to the proper pointer type.
 
 Line numbers in output file corrected.
 
-* Changes in version 1.22:
+* Noteworthy changes in release 1.22
 
 --help option added.
 
-* Changes in version 1.20:
+* Noteworthy changes in release 1.20
 
 Output file does not redefine const for C++.
 

THANKS

@@ -20,6 +20,7 @@ Anthony Heading           [email protected]
 Antonio Silva Correia     [email protected]
 Arnold Robbins            [email protected]
 Art Haas                  [email protected]
+Arthur Schwarz            [email protected]
 Askar Safin               [email protected]
 Balázs Scheidler          [email protected]
 Baron Schwartz            [email protected]
@@ -57,6 +58,7 @@ Derek M. Jones            [email protected]
 Di-an Jan                 [email protected]
 Dick Streefland           [email protected]
 Didier Godefroy           [email protected]
+Don Macpherson            [email protected]
 Efi Fogel                 [email protected]
 Enrico Scholz             [email protected]
 Eric Blake                [email protected]
@@ -154,6 +156,7 @@ Petr Machata              [email protected]
 Pho                       [email protected]
 Piotr Gackiewicz          [email protected]
 Piotr Marcińczyk          [email protected]
+Pramod Kumbhar            [email protected]
 Quentin Hocquet           [email protected]
 Quoc Peyrot               [email protected]
 R Blake                   [email protected]

TODO

@@ -25,9 +25,6 @@ should be updated to not use YYERRCODE.  Returning an undef token is good
 enough.
 
 ** Java
-*** Examples
-Have an example with a push parser.  Use autocompletion in that case.
-
 *** calc.at
 Stop hard-coding "Calc".  Adjust local.at (look for FIXME).
 
@@ -71,6 +68,55 @@ a bad feature.  On the other hand, that would make it much harder to sit
 push parsers on top of pull parser.  Which is currently not relevant, since
 push parsers are measurably slower.
 
+** %define parse.error formatted
+How about pushing bistromathics' yyreport_syntax_error as another standard
+way to generate the error message, and leave to the user the task of
+providing the message formats?  Currently in bistro, it reads:
+
+    const char *
+    error_format_string (int argc)
+    {
+      switch (argc)
+        {
+        default: /* Avoid compiler warnings. */
+        case 0: return _("%@: syntax error");
+        case 1: return _("%@: syntax error: unexpected %u");
+          // TRANSLATORS: '%@' is a location in a file, '%u' is an
+          // "unexpected token", and '%0e', '%1e'... are expected tokens
+          // at this point.
+          //
+          // For instance on the expression "1 + * 2", you'd get
+          //
+          // 1.5: syntax error: expected - or ( or number or function or variable before *
+        case 2: return _("%@: syntax error: expected %0e before %u");
+        case 3: return _("%@: syntax error: expected %0e or %1e before %u");
+        case 4: return _("%@: syntax error: expected %0e or %1e or %2e before %u");
+        case 5: return _("%@: syntax error: expected %0e or %1e or %2e or %3e before %u");
+        case 6: return _("%@: syntax error: expected %0e or %1e or %2e or %3e or %4e before %u");
+        case 7: return _("%@: syntax error: expected %0e or %1e or %2e or %3e or %4e or %5e before %u");
+        case 8: return _("%@: syntax error: expected %0e or %1e or %2e or %3e or %4e or %5e or %6e before %u");
+        }
+    }
+
+The message would have to be generated in a string, and pushed to yyerror.
+Which will be a pain in the neck in yacc.c.
+
+If we want to do that, we should think very carefully about the syntax of
+the format string.
+
+** yyclearin does not invoke the lookahead token's %destructor
+https://lists.gnu.org/r/bug-bison/2018-02/msg00000.html
+Rici:
+
+> Modifying yyclearin so that it calls yydestruct seems like the simplest
+> solution to this issue, but it is conceivable that such a change would
+> break programs which already perform some kind of workaround in order to
+> destruct the lookahead symbol. So it might be necessary to use some kind of
+> compatibility %define, or to create a new replacement macro with a
+> different name such as yydiscardin.
+>
+> At a minimum, the fact that yyclearin does not invoke the %destructor
+> should be highlighted in the documentation, since it is not at all obvious.
 
 * Bison 3.8
 ** Unit rules / Injection rules (Akim Demaille)
@@ -353,8 +399,12 @@ LORIA, INRIA Nancy - Grand Est, Nancy, France
 ** More languages?
 Well, only if there is really some demand for it.
 
+*** PHP
 https://github.com/scfc/bison-php/blob/master/data/lalr1.php
 
+*** Python
+https://lists.gnu.org/r/bison-patches/2013-09/msg00000.html and following
+
 ** Multiple start symbols
 Would be very useful when parsing closely related languages.  The idea is to
 declare several start symbols, for instance

configure.ac

@@ -261,9 +261,8 @@ if ! "$LEX_IS_FLEX" || test "X$LEX" = X:; then
   AC_MSG_WARN([bypassing lex because flex is required])
   LEX=:
 fi
-AM_CONDITIONAL([FLEX_WORKS], [$LEX_IS_FLEX])
-AM_CONDITIONAL([FLEX_CXX_WORKS],
-  [$LEX_IS_FLEX && test $bison_cv_cxx_works = yes])
+AM_CONDITIONAL([FLEX_WORKS], [$LEX_IS_FLEX && $FLEX_SUPPORTS_HEADER_OPT])
+AM_CONDITIONAL([FLEX_CXX_WORKS], [$LEX_WORKS && test $bison_cv_cxx_works = yes])
 AC_PROG_YACC
 AC_PROG_RANLIB
 AC_PROG_GNU_M4

data/skeletons/c++.m4

@@ -414,6 +414,9 @@ m4_define([b4_symbol_type_define],
       symbol_kind_type kind_;
     };
 
+    /// Backward compatibility for a private implementation detail.
+    typedef by_kind by_type;
+
     /// "External" symbols: returned by the scanner.
     struct symbol_type : basic_symbol<by_kind>
     {]b4_variant_if([[

data/skeletons/lalr1.cc

@@ -204,6 +204,13 @@ m4_define([b4_shared_declarations],
     ]b4_parser_class[ (]b4_parse_param_decl[);
     virtual ~]b4_parser_class[ ();
 
+#if 201103L <= YY_CPLUSPLUS
+    /// Non copyable.
+    ]b4_parser_class[ (const ]b4_parser_class[&) = delete;
+    /// Non copyable.
+    ]b4_parser_class[& operator= (const ]b4_parser_class[&) = delete;
+#endif
+
     /// Parse.  An alias for parse ().
     /// \returns  0 iff parsing succeeded.
     int operator() ();
@@ -255,10 +262,13 @@ m4_define([b4_shared_declarations],
     };
 ]])[
   private:
-    /// This class is not copyable.
+#if YY_CPLUSPLUS < 201103L
+    /// Non copyable.
     ]b4_parser_class[ (const ]b4_parser_class[&);
-    ]b4_parser_class[& operator= (const ]b4_parser_class[&);]b4_lac_if([[
-
+    /// Non copyable.
+    ]b4_parser_class[& operator= (const ]b4_parser_class[&);
+#endif
+]b4_lac_if([[
     /// Check the lookahead yytoken.
     /// \returns  true iff the token will be eventually shifted.
     bool yy_lac_check_ (symbol_kind_type yytoken) const;

data/skeletons/lalr1.java

@@ -121,7 +121,7 @@ import java.text.MessageFormat;
    * Locations represent a part of the input through the beginning
    * and ending positions.
    */
-  public class ]b4_location_type[ {
+  public static class ]b4_location_type[ {
     /**
      * The first, inclusive, position in the range.
      */
@@ -182,25 +182,24 @@ import java.text.MessageFormat;
 ]b4_token_enums[
     /** Deprecated, use ]b4_symbol(0, id)[ instead.  */
     public static final int EOF = ]b4_symbol(0, id)[;
-
-]b4_locations_if([[
+]b4_pull_if([b4_locations_if([[
     /**
      * Method to retrieve the beginning position of the last scanned token.
      * @@return the position at which the last scanned token starts.
      */
-    ]b4_position_type[ getStartPos ();
+    ]b4_position_type[ getStartPos();
 
     /**
      * Method to retrieve the ending position of the last scanned token.
      * @@return the first position beyond the last scanned token.
      */
-    ]b4_position_type[ getEndPos ();]])[
+    ]b4_position_type[ getEndPos();]])[
 
     /**
      * Method to retrieve the semantic value of the last scanned token.
      * @@return the semantic value of the last scanned token.
      */
-    ]b4_yystype[ getLVal ();
+    ]b4_yystype[ getLVal();
 
     /**
      * Entry point for the scanner.  Returns the token identifier corresponding
@@ -208,24 +207,25 @@ import java.text.MessageFormat;
      * ]b4_locations_if([and beginning/ending positions ])[of the token.
      * @@return the token identifier corresponding to the next token.
      */
-    int yylex ()]b4_maybe_throws([b4_lex_throws])[;
-
+    int yylex()]b4_maybe_throws([b4_lex_throws])[;
+]])[
     /**
-     * Entry point for error reporting.  Emits an error
-     * ]b4_locations_if([referring to the given location ])[in a user-defined way.
+     * Emit an error]b4_locations_if([ referring to the given location])[in a user-defined way.
      *
      *]b4_locations_if([[ @@param loc The location of the element to which the
-     *                error message is related]])[
+     *                error message is related.]])[
      * @@param msg The string for the error message.
      */
-     void yyerror (]b4_locations_if([b4_location_type[ loc, ]])[String msg);
+     void yyerror(]b4_locations_if([b4_location_type[ loc, ]])[String msg);
 
 ]b4_parse_error_bmatch(
            [custom], [[
     /**
-     * Build and emit a syntax error message.
+     * Build and emit a "syntax error" message in a user-defined way.
+     *
+     * @@param ctx  The context of the error.
      */
-     void reportSyntaxError (][Context yyctx);
+     void reportSyntaxError (][Context ctx);
 ]])[
   }
 
@@ -307,9 +307,8 @@ import java.text.MessageFormat;
    *]b4_locations_if([[ Use a <code>null</code> location.]])[
    * @@param msg The error message.
    */
-  public final void yyerror (String msg)
-  {
-    yylexer.yyerror (]b4_locations_if([[(]b4_location_type[)null, ]])[msg);
+  public final void yyerror(String msg) {
+      yylexer.yyerror(]b4_locations_if([[(]b4_location_type[)null, ]])[msg);
   }
 ]b4_locations_if([[
   /**
@@ -317,9 +316,8 @@ import java.text.MessageFormat;
    * @@param loc The location associated with the message.
    * @@param msg The error message.
    */
-  public final void yyerror (]b4_location_type[ loc, String msg)
-  {
-    yylexer.yyerror (loc, msg);
+  public final void yyerror(]b4_location_type[ loc, String msg) {
+      yylexer.yyerror(loc, msg);
   }
 
   /**
@@ -327,9 +325,8 @@ import java.text.MessageFormat;
    * @@param pos The position associated with the message.
    * @@param msg The error message.
    */
-  public final void yyerror (]b4_position_type[ pos, String msg)
-  {
-    yylexer.yyerror (new ]b4_location_type[ (pos), msg);
+  public final void yyerror(]b4_position_type[ pos, String msg) {
+      yylexer.yyerror(new ]b4_location_type[ (pos), msg);
   }]])[
 ]b4_parse_trace_if([[
   protected final void yycdebug (String s) {
@@ -469,7 +466,7 @@ import java.text.MessageFormat;
       return yydefgoto_[yysym - YYNTOKENS_];
   }
 
-  private int yyaction (int yyn, YYStack yystack, int yylen)]b4_maybe_throws([b4_throws])[
+  private int yyaction(int yyn, YYStack yystack, int yylen)]b4_maybe_throws([b4_throws])[
   {
     /* If YYLEN is nonzero, implement the default value of the action:
        '$$ = $1'.  Otherwise, use the top of the stack.
@@ -477,10 +474,10 @@ import java.text.MessageFormat;
        Otherwise, the following line sets YYVAL to garbage.
        This behavior is undocumented and Bison
        users should not rely upon it.  */
-    ]b4_yystype[ yyval = (0 < yylen) ? yystack.valueAt (yylen - 1) : yystack.valueAt (0);]b4_locations_if([[
-    ]b4_location_type[ yyloc = yylloc (yystack, yylen);]])[]b4_parse_trace_if([[
+    ]b4_yystype[ yyval = (0 < yylen) ? yystack.valueAt(yylen - 1) : yystack.valueAt(0);]b4_locations_if([[
+    ]b4_location_type[ yyloc = yylloc(yystack, yylen);]])[]b4_parse_trace_if([[
 
-    yyReducePrint (yyn, yystack);]])[
+    yyReducePrint(yyn, yystack);]])[
 
     switch (yyn)
       {
@@ -488,13 +485,13 @@ import java.text.MessageFormat;
         default: break;
       }]b4_parse_trace_if([[
 
-    yySymbolPrint ("-> $$ =", SymbolKind.get (yyr1_[yyn]), yyval]b4_locations_if([, yyloc])[);]])[
+    yySymbolPrint("-> $$ =", SymbolKind.get(yyr1_[yyn]), yyval]b4_locations_if([, yyloc])[);]])[
 
-    yystack.pop (yylen);
+    yystack.pop(yylen);
     yylen = 0;
     /* Shift the result of the reduction.  */
-    int yystate = yyLRGotoState (yystack.stateAt (0), yyr1_[yyn]);
-    yystack.push (yystate, yyval]b4_locations_if([, yyloc])[);
+    int yystate = yyLRGotoState(yystack.stateAt(0), yyr1_[yyn]);
+    yystack.push(yystate, yyval]b4_locations_if([, yyloc])[);
     return YYNEWSTATE;
   }
 
@@ -504,13 +501,14 @@ import java.text.MessageFormat;
   `--------------------------------*/
 
   private void yySymbolPrint(String s, SymbolKind yykind,
-                             ]b4_yystype[ yyvalue]b4_locations_if([, ]b4_location_type[ yylocation])[)
-  {
-    yycdebug (s
-              + (yykind.getCode() < YYNTOKENS_ ? " token " : " nterm ")
-              + yykind.getName() + " ("]b4_locations_if([
-              + yylocation + ": "])[
-              + (yyvalue == null ? "(null)" : yyvalue.toString()) + ")");
+                             ]b4_yystype[ yyvalue]b4_locations_if([, ]b4_location_type[ yylocation])[) {
+      if (0 < yydebug) {
+          yycdebug(s
+                   + (yykind.getCode() < YYNTOKENS_ ? " token " : " nterm ")
+                   + yykind.getName() + " ("]b4_locations_if([
+                   + yylocation + ": "])[
+                   + (yyvalue == null ? "(null)" : yyvalue.toString()) + ")");
+      }
   }]])[
 
 ]b4_push_if([],[[
@@ -521,7 +519,7 @@ import java.text.MessageFormat;
    * @@return <tt>true</tt> if the parsing succeeds.  Note that this does not
    *          imply that there were no syntax errors.
    */
-  public boolean parse ()]b4_maybe_throws([b4_list2([b4_lex_throws], [b4_throws])])[]])[
+  public boolean parse()]b4_maybe_throws([b4_list2([b4_lex_throws], [b4_throws])])[]])[
 ]b4_push_if([
   /**
    * Push Parse input from external lexer
@@ -532,7 +530,7 @@ import java.text.MessageFormat;
    *
    * @@return <tt>YYACCEPT, YYABORT, YYPUSH_MORE</tt>
    */
-  public int push_parse (int yylextoken, b4_yystype yylexval[]b4_locations_if([, b4_location_type yylexloc]))b4_maybe_throws([b4_list2([b4_lex_throws], [b4_throws])])])[
+  public int push_parse(int yylextoken, b4_yystype yylexval[]b4_locations_if([, b4_location_type yylexloc]))b4_maybe_throws([b4_list2([b4_lex_throws], [b4_throws])])])[
   {]b4_locations_if([[
     /* @@$.  */
     ]b4_location_type[ yyloc;]])[
@@ -612,8 +610,8 @@ b4_dollar_popdef[]dnl
 
         /* Convert token to internal form.  */
         yytoken = yytranslate_ (yychar);]b4_parse_trace_if([[
-        yySymbolPrint ("Next token is", yytoken,
-                       yylval]b4_locations_if([, yylloc])[);]])[
+        yySymbolPrint("Next token is", yytoken,
+                      yylval]b4_locations_if([, yylloc])[);]])[
 
         if (yytoken == SymbolKind.]b4_symbol_prefix[YYerror)
           {
@@ -649,8 +647,8 @@ b4_dollar_popdef[]dnl
             else
               {
                 /* Shift the lookahead token.  */]b4_parse_trace_if([[
-                yySymbolPrint ("Shifting", yytoken,
-                               yylval]b4_locations_if([, yylloc])[);
+                yySymbolPrint("Shifting", yytoken,
+                              yylval]b4_locations_if([, yylloc])[);
 ]])[
                 /* Discard the token being shifted.  */
                 yychar = YYEMPTY_;
@@ -683,7 +681,7 @@ b4_dollar_popdef[]dnl
       `-----------------------------*/
       case YYREDUCE:
         yylen = yyr2_[yyn];
-        label = yyaction (yyn, yystack, yylen);
+        label = yyaction(yyn, yystack, yylen);
         yystate = yystack.stateAt (0);
         break;
 
@@ -781,8 +779,8 @@ b4_dollar_popdef[]dnl
         yystack.pop (2);]])[
 
         /* Shift the error token.  */]b4_parse_trace_if([[
-        yySymbolPrint ("Shifting", SymbolKind.get (yystos_[yyn]),
-                       yylval]b4_locations_if([, yyloc])[);]])[
+        yySymbolPrint("Shifting", SymbolKind.get (yystos_[yyn]),
+                      yylval]b4_locations_if([, yyloc])[);]])[
 
         yystate = yyn;
         yystack.push (yyn, yylval]b4_locations_if([, yyloc])[);
@@ -833,7 +831,7 @@ b4_dollar_popdef[]dnl
     this.push_parse_initialized = true;
 
   }
-]b4_locations_if([
+]b4_locations_if([[
   /**
    * Push parse given input from an external lexer.
    *
@@ -843,36 +841,32 @@ b4_dollar_popdef[]dnl
    *
    * @@return <tt>YYACCEPT, YYABORT, YYPUSH_MORE</tt>
    */
-  public int push_parse (int yylextoken, b4_yystype yylexval, b4_position_type yylexpos)b4_maybe_throws([b4_list2([b4_lex_throws], [b4_throws])])
-  {
-    return push_parse (yylextoken, yylexval, new b4_location_type (yylexpos));
+  public int push_parse(int yylextoken, ]b4_yystype[ yylexval, ]b4_position_type[ yylexpos)]b4_maybe_throws([b4_list2([b4_lex_throws], [b4_throws])])[ {
+      return push_parse(yylextoken, yylexval, new ]b4_location_type[(yylexpos));
   }
-])[]])[
+]])])[
 
 ]b4_both_if([[
   /**
    * Parse input from the scanner that was specified at object construction
    * time.  Return whether the end of the input was reached successfully.
-   * This version of parse () is defined only when api.push-push=both.
+   * This version of parse() is defined only when api.push-push=both.
    *
    * @@return <tt>true</tt> if the parsing succeeds.  Note that this does not
    *          imply that there were no syntax errors.
    */
-  public boolean parse ()]b4_maybe_throws([b4_list2([b4_lex_throws], [b4_throws])])[
-  {
-    if (yylexer == null)
-      throw new NullPointerException("Null Lexer");
-    int status;
-    do {
-      int token = yylexer.yylex();
-      ]b4_yystype[ lval = yylexer.getLVal();
-]b4_locations_if([dnl
-      b4_location_type yyloc = new b4_location_type (yylexer.getStartPos (),
-                                            yylexer.getEndPos ());])[]b4_locations_if([[
-      status = push_parse(token,lval,yyloc);]], [[
-      status = push_parse(token,lval);]])[
-    } while (status == YYPUSH_MORE);
-    return (status == YYACCEPT);
+  public boolean parse()]b4_maybe_throws([b4_list2([b4_lex_throws], [b4_throws])])[ {
+      if (yylexer == null)
+          throw new NullPointerException("Null Lexer");
+      int status;
+      do {
+          int token = yylexer.yylex();
+          ]b4_yystype[ lval = yylexer.getLVal();]b4_locations_if([[
+          ]b4_location_type[ yyloc = new ]b4_location_type[(yylexer.getStartPos(), yylexer.getEndPos());
+          status = push_parse(token, lval, yyloc);]], [[
+          status = push_parse(token, lval);]])[
+      } while (status == YYPUSH_MORE);
+      return status == YYACCEPT;
   }
 ]])[
 
@@ -996,39 +990,39 @@ b4_dollar_popdef[]dnl
   }
 ]])[
 
-/**
-   * Report a syntax error.
+  /**
+   * Build and emit a "syntax error" message in a user-defined way.
+   *
+   * @@param ctx  The context of the error.
    */
-  private void yyreportSyntaxError (Context yyctx)
-  {]b4_parse_error_bmatch(
+  private void yyreportSyntaxError(Context yyctx) {]b4_parse_error_bmatch(
 [custom], [[
-    yylexer.reportSyntaxError (yyctx);]],
+      yylexer.reportSyntaxError(yyctx);]],
 [detailed\|verbose], [[
-    if (yyErrorVerbose)
-      {
-        final int argmax = 5;
-        SymbolKind[] yyarg = new SymbolKind[argmax];
-        int yycount = yysyntaxErrorArguments (yyctx, yyarg, argmax);
-        String[] yystr = new String[yycount];
-        for (int yyi = 0; yyi < yycount; ++yyi)
-          yystr[yyi] = yyarg[yyi].getName();
-        String yyformat;
-        switch (yycount)
-          {
-            default:
-            case 0: yyformat = ]b4_trans(["syntax error"])[; break;
-            case 1: yyformat = ]b4_trans(["syntax error, unexpected {0}"])[; break;
-            case 2: yyformat = ]b4_trans(["syntax error, unexpected {0}, expecting {1}"])[; break;
-            case 3: yyformat = ]b4_trans(["syntax error, unexpected {0}, expecting {1} or {2}"])[; break;
-            case 4: yyformat = ]b4_trans(["syntax error, unexpected {0}, expecting {1} or {2} or {3}"])[; break;
-            case 5: yyformat = ]b4_trans(["syntax error, unexpected {0}, expecting {1} or {2} or {3} or {4}"])[; break;
+      if (yyErrorVerbose) {
+          final int argmax = 5;
+          SymbolKind[] yyarg = new SymbolKind[argmax];
+          int yycount = yysyntaxErrorArguments(yyctx, yyarg, argmax);
+          String[] yystr = new String[yycount];
+          for (int yyi = 0; yyi < yycount; ++yyi) {
+              yystr[yyi] = yyarg[yyi].getName();
           }
-        yyerror (]b4_locations_if([[yyctx.yylocation, ]])[new MessageFormat (yyformat).format (yystr));
-        return;
-      }
-    yyerror (]b4_locations_if([[yyctx.yylocation, ]])["syntax error");]],
+          String yyformat;
+          switch (yycount) {
+              default:
+              case 0: yyformat = ]b4_trans(["syntax error"])[; break;
+              case 1: yyformat = ]b4_trans(["syntax error, unexpected {0}"])[; break;
+              case 2: yyformat = ]b4_trans(["syntax error, unexpected {0}, expecting {1}"])[; break;
+              case 3: yyformat = ]b4_trans(["syntax error, unexpected {0}, expecting {1} or {2}"])[; break;
+              case 4: yyformat = ]b4_trans(["syntax error, unexpected {0}, expecting {1} or {2} or {3}"])[; break;
+              case 5: yyformat = ]b4_trans(["syntax error, unexpected {0}, expecting {1} or {2} or {3} or {4}"])[; break;
+          }
+          yyerror(]b4_locations_if([[yyctx.yylocation, ]])[new MessageFormat(yyformat).format(yystr));
+      } else {
+          yyerror(]b4_locations_if([[yyctx.yylocation, ]])[]b4_trans(["syntax error"])[);
+      }]],
 [simple], [[
-    yyerror (]b4_locations_if([[yyctx.yylocation, ]])["syntax error");]])[
+      yyerror(]b4_locations_if([[yyctx.yylocation, ]])[]b4_trans(["syntax error"])[);]])[
   }
 
   /**
@@ -1074,10 +1068,10 @@ b4_dollar_popdef[]dnl
 
     /* The symbols being reduced.  */
     for (int yyi = 0; yyi < yynrhs; yyi++)
-      yySymbolPrint ("   $" + (yyi + 1) + " =",
-                     SymbolKind.get (yystos_[yystack.stateAt (yynrhs - (yyi + 1))]),
-                     ]b4_rhs_data(yynrhs, yyi + 1)b4_locations_if([,
-                     b4_rhs_location(yynrhs, yyi + 1)])[);
+      yySymbolPrint("   $" + (yyi + 1) + " =",
+                    SymbolKind.get (yystos_[yystack.stateAt (yynrhs - (yyi + 1))]),
+                    ]b4_rhs_data(yynrhs, yyi + 1)b4_locations_if([,
+                    b4_rhs_location(yynrhs, yyi + 1)])[);
   }]])[
 
   /* YYTRANSLATE_(TOKEN-NUM) -- Symbol number corresponding to TOKEN-NUM

data/skeletons/stack.hh

@@ -41,6 +41,13 @@ m4_define([b4_stack_define],
         : seq_ (n)
       {}
 
+#if 201103L <= YY_CPLUSPLUS
+      /// Non copyable.
+      stack (const stack&) = delete;
+      /// Non copyable.
+      stack& operator= (const stack&) = delete;
+#endif
+
       /// Random access.
       ///
       /// Index 0 returns the topmost element.
@@ -126,8 +133,12 @@ m4_define([b4_stack_define],
       };
 
     private:
+#if YY_CPLUSPLUS < 201103L
+      /// Non copyable.
       stack (const stack&);
+      /// Non copyable.
       stack& operator= (const stack&);
+#endif
       /// The wrapped container.
       S seq_;
     };

data/skeletons/variant.hh

@@ -115,6 +115,13 @@ m4_define([b4_value_type_declare],
       new (yyas_<T> ()) T (YY_MOVE (t));
     }
 
+#if 201103L <= YY_CPLUSPLUS
+    /// Non copyable.
+    semantic_type (const self_type&) = delete;
+    /// Non copyable.
+    self_type& operator= (const self_type&) = delete;
+#endif
+
     /// Destruction, allowed only if empty.
     ~semantic_type () YY_NOEXCEPT
     {]b4_parse_assert_if([
@@ -258,9 +265,12 @@ m4_define([b4_value_type_declare],
     }
 
   private:
-    /// Prohibit blind copies.
-    self_type& operator= (const self_type&);
+#if YY_CPLUSPLUS < 201103L
+    /// Non copyable.
     semantic_type (const self_type&);
+    /// Non copyable.
+    self_type& operator= (const self_type&);
+#endif
 
     /// Accessor to raw memory as \a T.
     template <typename T>

data/skeletons/yacc.c

@@ -132,6 +132,7 @@ m4_define([b4_rhs_value],
 # b4_lhs_location()
 # -----------------
 # Expansion of @$.
+# Overparenthetized to avoid obscure problems with "foo$$bar = foo$1bar".
 m4_define([b4_lhs_location],
 [(yyloc)])
 
@@ -140,6 +141,7 @@ m4_define([b4_lhs_location],
 # ---------------------------------
 # Expansion of @POS, where the current rule has RULE-LENGTH symbols
 # on RHS.
+# Overparenthetized to avoid obscure problems with "foo$$bar = foo$1bar".
 m4_define([b4_rhs_location],
 [(yylsp@{b4_subtract([$2], [$1])@})])
 
@@ -826,9 +828,8 @@ yy_reduce_print (yy_state_t *yyssp, YYSTYPE *yyvsp,]b4_locations_if([[ YYLTYPE *
       YYFPRINTF (stderr, "   $%d = ", yyi + 1);
       yy_symbol_print (stderr,
                        YY_ACCESSING_SYMBOL (+yyssp[yyi + 1 - yynrhs]),
-                       &]b4_rhs_value(yynrhs, yyi + 1)[
-                       ]b4_locations_if([, &]b4_rhs_location(yynrhs, yyi + 1))[]dnl
-                       b4_user_args[);
+                       &]b4_rhs_value(yynrhs, yyi + 1)[]b4_locations_if([,
+                       &]b4_rhs_location(yynrhs, yyi + 1))[]b4_user_args[);
       YYFPRINTF (stderr, "\n");
     }
 }
@@ -2052,10 +2053,8 @@ yyerrlab1:
   YY_IGNORE_MAYBE_UNINITIALIZED_END
 ]b4_locations_if([[
   yyerror_range[2] = yylloc;
-  /* Using YYLLOC is tempting, but would change the location of
-     the lookahead.  YYLOC is available though.  */
-  YYLLOC_DEFAULT (yyloc, yyerror_range, 2);
-  *++yylsp = yyloc;]])[
+  ++yylsp;
+  YYLLOC_DEFAULT (*yylsp, yyerror_range, 2);]])[
 
   /* Shift the error token.  */
   YY_SYMBOL_PRINT ("Shifting", YY_ACCESSING_SYMBOL (yyn), yyvsp, yylsp);

doc/bison.texi

@@ -2369,9 +2369,9 @@ yylex (void)
 @end group
 @end example
 
-Basically, the lexical analyzer performs the same processing as before:
-it skips blanks and tabs, and reads numbers or single-character tokens.
-In addition, it updates @code{yylloc}, the global variable (of type
+Basically, the lexical analyzer performs the same processing as before: it
+skips blanks and tabs, and reads numbers or single-character tokens.  In
+addition, it updates @code{yylloc}, the global variable (of type
 @code{YYLTYPE}) containing the token's location.
 
 Now, each time this function returns a token, the parser has its kind as
@@ -4505,12 +4505,17 @@ typedef struct YYLTYPE
 @} YYLTYPE;
 @end example
 
+While default locations represent a range in the source file(s), this is not
+a requirement.  It could be a single point or just a line number, or even
+more complex structures.
+
 When @code{YYLTYPE} is not defined, at the beginning of the parsing, Bison
 initializes all these fields to 1 for @code{yylloc}.  To initialize
 @code{yylloc} with a custom location type (or to chose a different
 initialization), use the @code{%initial-action} directive.  @xref{Initial
 Action Decl}.
 
+
 @node Actions and Locations
 @subsection Actions and Locations
 @cindex location actions
@@ -6132,7 +6137,7 @@ the @code{full} value was introduced in Bison 2.7
 @deffn Directive {%define api.push-pull} @var{kind}
 
 @itemize @bullet
-@item Language(s): C (deterministic parsers only)
+@item Language(s): C (deterministic parsers only), Java
 
 @item Purpose: Request a pull parser, a push parser, or both.
 @xref{Push Decl}.
@@ -9645,10 +9650,10 @@ and understand the parser run-time traces (@pxref{Tracing}).
 @node Understanding
 @section Understanding Your Parser
 
-As documented elsewhere (@pxref{Algorithm})
-Bison parsers are @dfn{shift/reduce automata}.  In some cases (much more
-frequent than one would hope), looking at this automaton is required to
-tune or simply fix a parser.
+As documented elsewhere (@pxref{Algorithm}) Bison parsers are
+@dfn{shift/reduce automata}.  In some cases (much more frequent than one
+would hope), looking at this automaton is required to tune or simply fix a
+parser.
 
 The textual file is generated when the options @option{--report} or
 @option{--verbose} are specified, see @ref{Invocation}.  Its name is made by
@@ -10604,6 +10609,26 @@ For compatibility with POSIX, the standard Bison distribution also contains
 a shell script called @command{yacc} that invokes Bison with the @option{-y}
 option.
 
+@sp 1
+
+The exit status of @command{bison} is:
+@table @asis
+@item 0 (success)
+when there were no errors.  Warnings, which are diagnostics about dubious
+constructs, do not change the exit status, unless they are turned into
+errors (@pxref{-Werror,,@option{-Werror}}).
+
+@item 1 (failure)
+when there were errors.  No file was generated (except the reports generated
+by @option{--verbose}, etc.).  In particular, the output files that possibly
+existed were not changed.
+
+@item 63 (mistmatch)
+when @command{bison} does not meet the version requirements of the grammar
+file. @xref{Require Decl}.  No file was generated or changed.
+@end table
+
+
 @menu
 * Bison Options::     All the options described in detail,
                         in alphabetical order by short options.
@@ -10997,6 +11022,7 @@ instance, @option{-Wno-yacc} will hide the warnings about
 POSIX Yacc incompatibilities.
 
 @item -Werror
+@anchor{-Werror}
 Turn enabled warnings for every @var{category} into errors, unless they are
 explicitly disabled by @option{-Wno-error=@var{category}}.
 
@@ -13001,9 +13027,6 @@ of the parser is always local to an instance of the parser class.
 Therefore, all Java parsers are ``pure'', and the @code{%define api.pure}
 directive does nothing when used in Java.
 
-Push parsers are currently unsupported in Java and @code{%define
-api.push-pull} have no effect.
-
 GLR parsers are currently unsupported in Java.  Do not use the
 @code{glr-parser} directive.
 
@@ -13318,9 +13341,9 @@ changed using @code{%define api.location.type @{@var{class-name}@}}.
 @end deftypemethod
 
 @deftypemethod {Lexer} {int} yylex ()
-Return the next token.  Its type is the return value, its semantic
-value and location are saved and returned by the their methods in the
-interface.
+Return the next token.  Its type is the return value, its semantic value and
+location are saved and returned by the their methods in the interface.  Not
+needed for push-only parsers.
 
 Use @samp{%define lex_throws} to specify any uncaught exceptions.
 Default is @code{java.io.IOException}.
@@ -13330,7 +13353,7 @@ Default is @code{java.io.IOException}.
 @deftypemethodx {Lexer} {Position} getEndPos ()
 Return respectively the first position of the last token that @code{yylex}
 returned, and the first position beyond it.  These methods are not needed
-unless location tracking is active.
+unless location tracking and pull parsing are active.
 
 They should return new objects for each call, to avoid that all the symbol
 share the same Position boundaries.
@@ -13340,7 +13363,8 @@ The return type can be changed using @code{%define api.position.type
 @end deftypemethod
 
 @deftypemethod {Lexer} {Object} getLVal ()
-Return the semantic value of the last token that yylex returned.
+Return the semantic value of the last token that yylex returned.  Not needed
+for push-only parsers.
 
 The return type can be changed using @samp{%define api.value.type
 @{@var{class-name}@}}.
@@ -14717,8 +14741,8 @@ In semantic actions, it stores the location of the lookahead token.
 @end deffn
 
 @deffn {Type} YYLTYPE
-Data type of @code{yylloc}; by default, a structure with four
-members.  @xref{Location Type}.
+Data type of @code{yylloc}.  By default in C, a structure with four members
+(start/end line/column).  @xref{Location Type}.
 @end deffn
 
 @deffn {Variable} yylval

examples/c/bistromathic/Makefile

@@ -5,7 +5,7 @@ BASE = bistromathic
 BISON = bison
 XSLTPROC = xsltproc
 
-# We need to find the headers and libs for readline and intl.
+# We need to find the headers and libs for readline (and possibly intl).
 # You probably need to customize this for your own environment.
 CPPFLAGS = -I/opt/local/include
 LDFLAGS = -L/opt/local/lib
@@ -14,7 +14,7 @@ LDFLAGS = -L/opt/local/lib
 BISON_LOCALEDIR = $(shell $(BISON) $(BISON_FLAGS) --print-localedir)
 CPPFLAGS += -DENABLE_NLS -DBISON_LOCALEDIR='"$(BISON_LOCALEDIR)"'
 
-LIBS = -lreadline -lintl
+LIBS = -lreadline -lm # In some environments, -lintl is needed.
 
 all: $(BASE)
 

examples/c/bistromathic/bistromathic.test

@@ -15,12 +15,30 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-# macOS' version of readline does not repeat stdin on stdout in
-# non-interactive mode.
-if ! echo '1-1' | prog | grep '1-1' >/dev/null; then
-   strip_prompt=true
+
+# Beware of portability issues of readline when not feeding it from a
+# terminal.
+#
+# With recent versions of GNU Readline, input "1+2*3\n" gives
+# "> 1+2*3\n7\n> \n"
+#
+# macOS' version does not display the prompt and does not repeat stdin
+# on stdout, so input "1+2*3\n" gives "7\n" as output.  Let's try to
+# cope with this.
+#
+# On OpenBSD 6.5 the prompt is displayed, but the input is not
+# repeated (!).  So input "1+2*3\n" gives "> 7\n> \n" as output.
+
+if ! echo '1-1' | prog | grep '>' >/dev/null; then
+    # macOS.
+    strip_prompt=true
+elif ! echo '1-1' | prog | grep '1-1' >/dev/null; then
+    # OpenBSD 6.5.  I don't want to spend time on this.
+    echo "SKIP: this is not the GNU Readline we expect"
+    exit 0
 fi
 
+
 cat >input <<EOF
 1+2*3
 EOF

examples/c/bistromathic/parse.y

@@ -2,6 +2,7 @@
 
 %code top {
   #include <ctype.h>  // isdigit
+  #include <locale.h> // LC_ALL
   #include <math.h>   // cos, sin, etc.
   #include <stdarg.h> // va_start
   #include <stdio.h>  // printf

examples/c/reccalc/Makefile

@@ -12,7 +12,7 @@ all: $(BASE)
 	$(BISON) $(BISONFLAGS) --defines --xml --graph=$*.gv -o $*.c $<
 
 %.c %.h: %.l
-	$(FLEX) $(FLEXFLAGS) -o$*.c --header-file=$*.h $<
+	$(FLEX) $(FLEXFLAGS) -o$*.c --header=$*.h $<
 
 scan.o: parse.h
 parse.o: scan.h

examples/c/reccalc/local.mk

@@ -69,7 +69,9 @@ DASH = -
 	$(AM_V_LEX)rm -f $@ $@.tmp
 	$(AM_V_at)$(MKDIR_P) %D%
 	$(AM_V_at)touch $@.tmp
-	$(AM_V_at)$(LEX) $(AM_LFLAGS) $(LFLAGS) -o%D%/scan.c --header-file=%D%/scan.h $(srcdir)/%D%/scan.l
+## --header introduced in 2.5.6, renamed as --header-file in 2.6.4.
+## Backward compatibility ensured since --header is an unambiguous prefix.
+	$(AM_V_at)$(LEX) $(AM_LFLAGS) $(LFLAGS) -o%D%/scan.c --header=%D%/scan.h $(srcdir)/%D%/scan.l
 	$(AM_V_at)mv $@.tmp $@
 
 

examples/java/README.md

@@ -9,7 +9,7 @@ afterwards.
 The usual calculator, a very simple version.
 
 ## calc/Calc.y
-The calculator, but with location tracking and debug traces.
+The calculator, but with location tracking, debug traces, and a push parser.
 
 <!---
 

examples/java/calc/Calc.y

@@ -2,6 +2,7 @@
 
 %define api.parser.class {Calc}
 %define api.parser.public
+%define api.push-pull push
 
 %define parse.error custom
 %define parse.trace
@@ -20,12 +21,19 @@
 
 %code {
   public static void main(String[] args) throws IOException {
-    CalcLexer l = new CalcLexer(System.in);
-    Calc p = new Calc(l);
+    CalcLexer scanner = new CalcLexer(System.in);
+    Calc parser = new Calc(scanner);
     for (String arg : args)
       if (arg.equals("-p"))
-        p.setDebugLevel(1);
-    if (!p.parse())
+        parser.setDebugLevel(1);
+    int status;
+    do {
+      int token = scanner.getToken();
+      Object lval = scanner.getValue();
+      Calc.Location yyloc = scanner.getLocation();
+      status = parser.push_parse(token, lval, yyloc);
+    } while (status == Calc.YYPUSH_MORE);
+    if (status != Calc.YYACCEPT)
       System.exit(1);
   }
 
@@ -105,14 +113,17 @@ class CalcLexer implements Calc.Lexer {
   Position start = new Position(1, 0);
   Position end = new Position(1, 0);
 
-  public Position getStartPos() {
-    return new Position(start);
-  }
-
-  public Position getEndPos() {
-    return new Position(end);
+  /**
+   * The location of the last token read.
+   * Implemented with getStartPos and getEndPos in pull parsers.
+   */
+  public Calc.Location getLocation() {
+    return new Calc.Location(new Position(start), new Position(end));
   }
 
+  /**
+   * Build and emit a syntax error message.
+   */
   public void reportSyntaxError(Calc.Context ctx) {
     System.err.print(ctx.getLocation() + ": syntax error");
     {
@@ -131,20 +142,33 @@ class CalcLexer implements Calc.Lexer {
     System.err.println("");
   }
 
-  public void yyerror(Calc.Location l, String s) {
-    if (l == null)
-      System.err.println(s);
+  /**
+   * Emit an error referring to the given location in a user-defined way.
+   *
+   * @@param loc The location of the element to which the
+   *                error message is related.
+   * @@param msg The string for the error message.
+   */
+  public void yyerror(Calc.Location loc, String msg) {
+    if (loc == null)
+      System.err.println(msg);
     else
-      System.err.println(l + ": " + s);
+      System.err.println(loc + ": " + msg);
   }
 
   Integer yylval;
 
-  public Object getLVal() {
+  /**
+   * The value of the last token read.  Called getLVal in pull parsers.
+   */
+  public Object getValue() {
     return yylval;
   }
 
-  public int yylex() throws IOException {
+  /**
+   * Fetch the next token.  Called yylex in pull parsers.
+   */
+  public int getToken() throws IOException {
     start.set(reader.getPosition());
     int ttype = st.nextToken();
     end.set(reader.getPosition());
@@ -160,7 +184,7 @@ class CalcLexer implements Calc.Lexer {
       end.set(reader.getPreviousPosition());
       return NUM;
     case ' ': case '\t':
-      return yylex();
+      return getToken();
     case '!':
       return BANG;
     case '+':
@@ -185,7 +209,9 @@ class CalcLexer implements Calc.Lexer {
   }
 }
 
-
+/**
+ * A class defining a point in the input.
+ */
 class Position {
   public int line = 1;
   public int column = 1;
@@ -227,6 +253,9 @@ class Position {
   }
 }
 
+/**
+ * A Stream reader that keeps track of the current Position.
+ */
 class PositionReader extends BufferedReader {
 
   private Position position = new Position();

m4/flex.m4

@@ -41,6 +41,22 @@ else
 fi
 ])
 
+
+AC_CACHE_CHECK([whether flex supports --header=FILE],
+                [ac_cv_prog_lex_supports_header_opt],
+[if _AC_DO_VAR([LEX --header=conftest.h conftest.l]); then
+  ac_cv_prog_lex_supports_header_opt=yes
+else
+  ac_cv_prog_lex_supports_header_opt=no
+fi
+])
+if test "$ac_cv_prog_lex_supports_header_opt" = yes; then
+  FLEX_SUPPORTS_HEADER_OPT=true
+else
+  FLEX_SUPPORTS_HEADER_OPT=false
+fi
+
+
 cat >conftest.l <<_ACEOF[
 %%
 a { ECHO; }

src/parse-gram.c

@@ -1,4 +1,4 @@
-/* A Bison parser, made by GNU Bison 3.5.90.  */
+/* A Bison parser, made by GNU Bison 3.5.91.  */
 
 /* Bison implementation for Yacc-like parsers in C
 
@@ -49,7 +49,7 @@
 #define YYBISON 1
 
 /* Bison version.  */
-#define YYBISON_VERSION "3.5.90"
+#define YYBISON_VERSION "3.5.91"
 
 /* Skeleton name.  */
 #define YYSKELETON_NAME "yacc.c"
@@ -1304,8 +1304,8 @@ yy_reduce_print (yy_state_t *yyssp, YYSTYPE *yyvsp, YYLTYPE *yylsp,
       YYFPRINTF (stderr, "   $%d = ", yyi + 1);
       yy_symbol_print (stderr,
                        YY_ACCESSING_SYMBOL (+yyssp[yyi + 1 - yynrhs]),
-                       &yyvsp[(yyi + 1) - (yynrhs)]
-                       , &(yylsp[(yyi + 1) - (yynrhs)])                       );
+                       &yyvsp[(yyi + 1) - (yynrhs)],
+                       &(yylsp[(yyi + 1) - (yynrhs)]));
       YYFPRINTF (stderr, "\n");
     }
 }
@@ -2738,10 +2738,8 @@ yyerrlab1:
   YY_IGNORE_MAYBE_UNINITIALIZED_END
 
   yyerror_range[2] = yylloc;
-  /* Using YYLLOC is tempting, but would change the location of
-     the lookahead.  YYLOC is available though.  */
-  YYLLOC_DEFAULT (yyloc, yyerror_range, 2);
-  *++yylsp = yyloc;
+  ++yylsp;
+  YYLLOC_DEFAULT (*yylsp, yyerror_range, 2);
 
   /* Shift the error token.  */
   YY_SYMBOL_PRINT ("Shifting", YY_ACCESSING_SYMBOL (yyn), yyvsp, yylsp);

src/parse-gram.h

@@ -1,4 +1,4 @@
-/* A Bison parser, made by GNU Bison 3.5.90.  */
+/* A Bison parser, made by GNU Bison 3.5.91.  */
 
 /* Bison interface for Yacc-like parsers in C
 

src/state.h

@@ -67,7 +67,10 @@
    Conflict resolution can decide that certain tokens in certain
    states should explicitly be errors (for implementing %nonassoc).
    For each state, the tokens that are errors for this reason are
-   recorded in an errs structure, which holds the token numbers.
+   recorded in an errs structure.  The generated parser does not
+   depend on this errs structure, it is used only in the reports
+   (*.output, etc.) to describe conflicted actions that have been
+   discarded.
 
    There is at least one goto transition present in state zero.  It
    leads to a next-to-final state whose accessing_symbol is the

tests/diagnostics.at

@@ -220,15 +220,14 @@ exp: an\005error.
 
 AT_TEST([[Tabulations and multibyte characters]],
 [[%%
-exp: a b c d e f g h
+exp: a b c d e f g
 a: {		}
 b: {            }
 c: {------------}
 d: {éééééééééééé}
-e: {∇⃗×𝐸⃗ = -∂𝐵⃗/∂t}
-f: {	42	}
-g: {	"฿¥$€₦"	}
-h: {	🐃	}
+e: {	42	}
+f: {	"฿¥$€₦"	}
+g: {	🐃	}
 ]],
 [0],
 [[input.y:11.4-17: <warning>warning:</warning> empty rule without %empty [<warning>-Wempty-rule</warning>]
@@ -248,24 +247,39 @@ input.y:14.4-17: <warning>warning:</warning> empty rule without %empty [<warning
       |    <warning>^~~~~~~~~~~~~~</warning>
       |    <fixit-insert>%empty</fixit-insert>
 input.y:15.4-17: <warning>warning:</warning> empty rule without %empty [<warning>-Wempty-rule</warning>]
-   15 | e: <warning>{∇⃗×𝐸⃗ = -∂𝐵⃗/∂t}</warning>
+   15 | e: <warning>{	42	}</warning>
       |    <warning>^~~~~~~~~~~~~~</warning>
       |    <fixit-insert>%empty</fixit-insert>
 input.y:16.4-17: <warning>warning:</warning> empty rule without %empty [<warning>-Wempty-rule</warning>]
-   16 | f: <warning>{	42	}</warning>
+   16 | f: <warning>{	"฿¥$€₦"	}</warning>
       |    <warning>^~~~~~~~~~~~~~</warning>
       |    <fixit-insert>%empty</fixit-insert>
 input.y:17.4-17: <warning>warning:</warning> empty rule without %empty [<warning>-Wempty-rule</warning>]
-   17 | g: <warning>{	"฿¥$€₦"	}</warning>
-      |    <warning>^~~~~~~~~~~~~~</warning>
-      |    <fixit-insert>%empty</fixit-insert>
-input.y:18.4-17: <warning>warning:</warning> empty rule without %empty [<warning>-Wempty-rule</warning>]
-   18 | h: <warning>{	🐃	}</warning>
+   17 | g: <warning>{	🐃	}</warning>
       |    <warning>^~~~~~~~~~~~~~</warning>
       |    <fixit-insert>%empty</fixit-insert>
 input.y: <warning>warning:</warning> fix-its can be applied.  Rerun with option '--update'. [<warning>-Wother</warning>]
 ]])
 
+# Likewise, but currently not portable to Cygwin.
+# https://lists.gnu.org/r/bug-bison/2020-05/msg00003.html.
+case `uname -a` in
+  (CYGWIN*);;
+  (*)
+AT_TEST([[Tabulations and multibyte characters]],
+[[%%
+e: {∇⃗×𝐸⃗ = -∂𝐵⃗/∂t}
+]],
+[0],
+[[input.y:10.4-17: <warning>warning:</warning> empty rule without %empty [<warning>-Wempty-rule</warning>]
+   10 | e: <warning>{∇⃗×𝐸⃗ = -∂𝐵⃗/∂t}</warning>
+      |    <warning>^~~~~~~~~~~~~~</warning>
+      |    <fixit-insert>%empty</fixit-insert>
+input.y: <warning>warning:</warning> fix-its can be applied.  Rerun with option '--update'. [<warning>-Wother</warning>]
+]])
+;;
+esac
+
 
 ## --------------- ##
 ## Special files.  ##

tests/java.at

@@ -18,9 +18,9 @@
 AT_BANNER([[Java Calculator.]])
 
 
-# ------------------------- #
-# Java invalid directives.  #
-# ------------------------- #
+## ------------------------- ##
+## Java invalid directives.  ##
+## ------------------------- ##
 
 AT_SETUP([Java invalid directives])
 
@@ -42,9 +42,9 @@ YYParser.y:4.13-30: error: %destructor does not make sense in Java
 AT_CLEANUP
 
 
-# ------------------------- #
-# Helping Autotest macros.  #
-# ------------------------- #
+## ------------------------- ##
+## Helping Autotest macros.  ##
+## ------------------------- ##
 
 
 # AT_JAVA_POSITION_DEFINE_OLD
@@ -91,9 +91,9 @@ m4_define([AT_JAVA_POSITION_DEFINE_OLD],
 
 
 
-# -----------------#
-# Java Parameters. #
-# -----------------#
+## ----------------- ##
+## Java Parameters.  ##
+## ----------------- ##
 
 AT_BANNER([Java Parameters.])
 
@@ -146,7 +146,7 @@ m4_define([AT_CHECK_JAVA_MINIMAL_W_LEXER],
     System.err.println (loc + ": " + s);
   }
 
-  public int yylex ()$2
+  public int yylex()$2
   {
     $3
   }
@@ -164,9 +164,9 @@ m4_define([AT_CHECK_JAVA_GREP],
 ])])
 
 
-# ------------------------------------- #
-# Java parser class and package names.  #
-# ------------------------------------- #
+## ------------------------------------- ##
+## Java parser class and package names.  ##
+## ------------------------------------- ##
 
 AT_SETUP([Java parser class and package names])
 
@@ -191,9 +191,9 @@ AT_CHECK_JAVA_GREP([[package user_java_package;]])
 AT_CLEANUP
 
 
-# ----------------------------- #
-# Java parser class modifiers.  #
-# ----------------------------- #
+## ----------------------------- ##
+## Java parser class modifiers.  ##
+## ----------------------------- ##
 
 AT_SETUP([Java parser class modifiers])
 
@@ -255,9 +255,9 @@ AT_CHECK_JAVA_GREP([[/\*@Deprecated @SuppressWarnings("unchecked") @SuppressWarn
 AT_CLEANUP
 
 
-# ---------------------------------------- #
-# Java parser class extends and implements #
-# ---------------------------------------- #
+## ---------------------------------------- ##
+## Java parser class extends and implements ##
+## ---------------------------------------- ##
 
 AT_SETUP([Java parser class extends and implements])
 
@@ -275,9 +275,9 @@ AT_CHECK_JAVA_GREP([[class YYParser extends Thread implements Cloneable]])
 AT_CLEANUP
 
 
-# -------------------------------- #
-# Java %parse-param and %lex-param #
-# -------------------------------- #
+## -------------------------------- ##
+## Java %parse-param and %lex-param ##
+## -------------------------------- ##
 
 AT_SETUP([Java %parse-param and %lex-param])
 
@@ -349,9 +349,9 @@ AT_CHECK_JAVA_GREP([[ *this.parse_param2 = parse_param2;]], [2])
 AT_CLEANUP
 
 
-# ------------------------- #
-# Java throw specifications #
-# ------------------------- #
+## --------------------------- ##
+## Java throw specifications.  ##
+## --------------------------- ##
 
 AT_SETUP([Java throws specifications])
 
@@ -430,17 +430,17 @@ AT_JT_initial_action],
 [AT_JT_yylex_action],
 [],
 [AT_JT_parse_action])])
-AT_CHECK_JAVA_GREP([[ *int yylex ()]AT_JT_yylex_throws *[;]])
-AT_CHECK_JAVA_GREP([[ *private int yyaction ([^)]*)]AT_JT_yyaction_throws[ *]])
-AT_CHECK_JAVA_GREP([[ *public boolean parse ()]AT_JT_parse_throws[ *]])
+AT_CHECK_JAVA_GREP([[ *int yylex()]AT_JT_yylex_throws *[;]])
+AT_CHECK_JAVA_GREP([[ *private int yyaction([^)]*)]AT_JT_yyaction_throws[ *]])
+AT_CHECK_JAVA_GREP([[ *public boolean parse()]AT_JT_parse_throws[ *]])
 ])])])
 
 AT_CLEANUP
 
 
-# ------------------------------------- #
-# Java constructor init and init_throws #
-# ------------------------------------- #
+## --------------------------------------- ##
+## Java constructor init and init_throws.  ##
+## --------------------------------------- ##
 
 AT_SETUP([Java constructor init and init_throws])
 
@@ -465,9 +465,9 @@ m4_popdef([AT_Witness])
 AT_CLEANUP
 
 
-# ------------------------------------------ #
-# Java value, position, and location types.  #
-# ------------------------------------------ #
+## ------------------------------------------ ##
+## Java value, position, and location types.  ##
+## ------------------------------------------ ##
 
 AT_SETUP([Java value, position, and location types])
 
@@ -496,9 +496,9 @@ AT_CHECK([[$EGREP -v ' */?\*' YYParser.java | grep -w 'Location']], [1], [ignore
 AT_CLEANUP
 
 
-# ----------------------------------------------- #
-# Java syntax error handling without error token. #
-# ----------------------------------------------- #
+## ------------------------------------------------ ##
+## Java syntax error handling without error token.  ##
+## ------------------------------------------------ ##
 
 AT_SETUP([Java syntax error handling without error token])
 

tests/javapush.at

@@ -180,28 +180,28 @@ AT_DATA([[input.y]],
 # Verify that the proper procedure(s) are generated for each case.
 AT_BISON_CHECK([[-Dapi.push-pull=pull -o Main.java input.y]])
 AT_CHECK_JAVA_GREP([[Main.java]],
-                   [[.*public boolean parse ().*]],
+                   [[.*public boolean parse().*]],
                    [1])
 # If BISON_USE_PUSH_FOR_PULL is set, then we have one occurrence of
 # this function, otherwise it should not be there.
 AT_CHECK_JAVA_GREP([[Main.java]],
-        [[.*public int push_parse (int yylextoken, Object yylexval).*]],
+        [[.*public int push_parse(int yylextoken, Object yylexval).*]],
         [${BISON_USE_PUSH_FOR_PULL-0}])
 
 AT_BISON_CHECK([[-Dapi.push-pull=both -o Main.java input.y]])
 AT_CHECK_JAVA_GREP([[Main.java]],
-                   [[.*public boolean parse ().*]],
+                   [[.*public boolean parse().*]],
                    [1])
 AT_CHECK_JAVA_GREP([[Main.java]],
-        [[.*public int push_parse (int yylextoken, Object yylexval).*]],
+        [[.*public int push_parse(int yylextoken, Object yylexval).*]],
         [1])
 
 AT_BISON_CHECK([[-Dapi.push-pull=push -o Main.java input.y]])
 AT_CHECK_JAVA_GREP([[Main.java]],
-                   [[.*public boolean parse ().*]],
+                   [[.*public boolean parse().*]],
                    [0])
 AT_CHECK_JAVA_GREP([[Main.java]],
-        [[.*public int push_parse (int yylextoken, Object yylexval).*]],
+        [[.*public int push_parse(int yylextoken, Object yylexval).*]],
         [1])
 
 AT_JAVA_COMPILE([[Main.java]])