Document Yacc prologue alternatives and default %destructor's and

%printer's as experimental.  Don't mention Java yet.  Discussed at
<http://lists.gnu.org/archive/html/bison-patches/2006-12/msg00002.html>.
* NEWS (2.3a+): Say they're experimental.  Remove any mention of Java.
(2.3a): Annotate this entry to say the old forms of these features were
also experimental.
* doc/bison.texinfo (Prologue Alternatives, Freeing Discarded Symbols,
Bison Symbols): Say they're experimental.  Comment out any mention
of Java (we'll want this back eventually).

ChangeLog

@@ -1,3 +1,15 @@
+2006-12-05  Joel E. Denny  <jdenny@ces.clemson.edu>
+
+	Document Yacc prologue alternatives and default %destructor's and
+	%printer's as experimental.  Don't mention Java yet.  Discussed at
+	<http://lists.gnu.org/archive/html/bison-patches/2006-12/msg00002.html>.
+	* NEWS (2.3a+): Say they're experimental.  Remove any mention of Java.
+	(2.3a): Annotate this entry to say the old forms of these features were
+	also experimental.
+	* doc/bison.texinfo (Prologue Alternatives, Freeing Discarded Symbols,
+	Bison Symbols): Say they're experimental.  Comment out any mention
+	of Java (we'll want this back eventually).
+
 2006-12-01  Joel E. Denny  <jdenny@ces.clemson.edu>
 
 	Support a file name argument to %defines.  Deprecate `=' in

NEWS

@@ -54,6 +54,10 @@ Changes in version 2.3a+ (????-??-??):
   longer applies any %destructor to a mid-rule value if that mid-rule value is
   not actually ever referenced using either $$ or $n in a semantic action.
 
+  The default %destructor's and %printer's are experimental.  More user
+  feedback will help to determine whether they should become permanent
+  features.
+
   See the section `Freeing Discarded Symbols' in the Bison manual for further
   details.
 
@@ -63,68 +67,68 @@ Changes in version 2.3a+ (????-??-??):
     1. %code {CODE}
 
        Other than semantic actions, this is probably the most common place you
-       should write verbatim code for the parser implementation.  For C/C++, it
+       should write verbatim code for the parser implementation.  It replaces
-       replaces the traditional Yacc prologue, `%{CODE%}', for most purposes.
+       the traditional Yacc prologue, `%{CODE%}', for most purposes.  Compare
-       For Java, it inserts your CODE into the parser class.  Compare with:
+       with:
 
-         - `%{CODE%}' appearing after the first `%union {CODE}' in a C/C++
+         - `%{CODE%}' appearing after the first `%union {CODE}' in a grammar
-           based grammar file.  While Bison will continue to support `%{CODE%}'
+	   file.  While Bison will continue to support `%{CODE%}' for backward
-           for backward compatibility, `%code {CODE}' is cleaner as its
+	   compatibility, `%code {CODE}' is cleaner as its functionality does
-           functionality does not depend on its position in the grammar file
+	   not depend on its position in the grammar file relative to any
-           relative to any `%union {CODE}'.  Specifically, `%code {CODE}'
+	   `%union {CODE}'.  Specifically, `%code {CODE}' always inserts your
-           always inserts your CODE into the parser code file after the usual
+	   CODE into the parser code file after the usual contents of the
-           contents of the parser header file.
+	   parser header file.
          - `%after-header {CODE}', which only Bison 2.3a supported.
 
     2. %requires {CODE}
 
        This is the right place to write dependency code for externally exposed
-       definitions required by Bison.  For C/C++, such exposed definitions are
+       definitions required by Bison.  Such exposed definitions are those
-       those usually appearing in the parser header file.  Thus, this is the
+       usually appearing in the parser header file.  Thus, this is the right
-       right place to define types referenced in `%union {CODE}' directives,
+       place to define types referenced in `%union {CODE}' directives, and it
-       and it is the right place to override Bison's default YYSTYPE and
+       is the right place to override Bison's default YYSTYPE and YYLTYPE
-       YYLTYPE definitions.  For Java, this is the right place to write import
+       definitions.  Compare with:
-       directives.  Compare with:
 
-         - `%{CODE%}' appearing before the first `%union {CODE}' in a C/C++
+         - `%{CODE%}' appearing before the first `%union {CODE}' in a grammar
-           based grammar file.  Unlike `%{CODE%}', `%requires {CODE}' inserts
+           file.  Unlike `%{CODE%}', `%requires {CODE}' inserts your CODE both
-           your CODE both into the parser code file and into the parser header
+           into the parser code file and into the parser header file since
-           file since Bison's required definitions should depend on it in both
+           Bison's required definitions should depend on it in both places.
-           places.
          - `%start-header {CODE}', which only Bison 2.3a supported.
 
     3. %provides {CODE}
     
        This is the right place to write additional definitions you would like
-       Bison to expose externally.  For C/C++, this directive inserts your CODE
+       Bison to expose externally.  That is, this directive inserts your CODE
        both into the parser header file and into the parser code file after
-       Bison's required definitions.  For Java, it inserts your CODE into the
+       Bison's required definitions.  Compare with:
-       parser java file after the parser class.  Compare with:
 
          - `%end-header {CODE}', which only Bison 2.3a supported.
 
     4. %code-top {CODE}
 
-       Occasionally for C/C++ it is desirable to insert code near the top of
+       Occasionally it is desirable to insert code near the top of the parser
-       the parser code file.  For example:
+       code file.  For example:
 
          %code-top {
            #define _GNU_SOURCE
            #include <stdio.h>
          }
 
-       For Java, `%code-top {CODE}' is currently unused.  Compare with:
+       Compare with:
 
-         - `%{CODE%}' appearing before the first `%union {CODE}' in a C/C++
+         - `%{CODE%}' appearing before the first `%union {CODE}' in a grammar
-           based grammar file.  `%code-top {CODE}' is cleaner as its
+           file.  `%code-top {CODE}' is cleaner as its functionality does not
-           functionality does not depend on its position in the grammar file
+           depend on its position in the grammar file relative to any
-           relative to any `%union {CODE}'.
+           `%union {CODE}'.
          - `%before-header {CODE}', which only Bison 2.3a supported.
 
   If you have multiple occurrences of any one of the above four directives,
   Bison will concatenate the contents in the order they appear in the grammar
   file.
 
+  The prologue alternatives are experimental.  More user feedback will help to
+  determine whether they should become permanent features.
+
   Also see the new section `Prologue Alternatives' in the Bison manual.
 
 Changes in version 2.3a, 2006-09-13:
@@ -160,6 +164,10 @@ Changes in version 2.3a, 2006-09-13:
   also prints its line number to `stdout'.  It performs only the second
   `%destructor' in this case, so it invokes `free' only once.
 
+  [Although we failed to mention this here in the 2.3a release, the default
+  %destructor's and %printer's were experimental, and they were rewritten in
+  future versions.]
+
 * Except for LALR(1) parsers in C with POSIX Yacc emulation enabled (with `-y',
   `--yacc', or `%yacc'), Bison no longer generates #define statements for
   associating token numbers with token names.  Removing the #define statements
@@ -230,6 +238,9 @@ Changes in version 2.3a, 2006-09-13:
   If you have multiple occurrences of any one of the above declarations, Bison
   will concatenate the contents in declaration order.
 
+  [Although we failed to mention this here in the 2.3a release, the prologue
+  alternatives were experimental, and they were rewritten in future versions.]
+
 * The option `--report=look-ahead' has been changed to `--report=lookahead'.
   The old spelling still works, but is not documented and may be removed
   in a future release.

doc/bison.texinfo

@@ -2684,6 +2684,10 @@ feature test macros can affect the behavior of Bison-generated
 @findex %requires
 @findex %provides
 @findex %code-top
+(The prologue alternatives described here are experimental.
+More user feedback will help to determine whether they should become permanent
+features.)
+
 The functionality of @var{Prologue} sections can often be subtle and
 inflexible.
 As an alternative, Bison provides a set of more explicit directives:
@@ -4271,6 +4275,9 @@ grammar symbol that has that semantic type tag unless that symbol has its own
 per-symbol @code{%destructor}.
 
 Finally, you can define two different kinds of default @code{%destructor}s.
+(These default forms are experimental.
+More user feedback will help to determine whether they should become permanent
+features.)
 You can place each of @code{<*>} and @code{<>} in the @var{symbols} list of
 exactly one @code{%destructor} declaration in your grammar file.
 The parser will invoke the @var{code} associated with one of these whenever it
@@ -8573,12 +8580,22 @@ Separates alternate rules for the same result nonterminal.
 @deffn {Directive} <*>
 Used to define a default tagged @code{%destructor} or default tagged
 @code{%printer}.
+
+This feature is experimental.
+More user feedback will help to determine whether it should become a permanent
+feature.
+
 @xref{Destructor Decl, , Freeing Discarded Symbols}.
 @end deffn
 
 @deffn {Directive} <>
 Used to define a default tagless @code{%destructor} or default tagless
 @code{%printer}.
+
+This feature is experimental.
+More user feedback will help to determine whether it should become a permanent
+feature.
+
 @xref{Destructor Decl, , Freeing Discarded Symbols}.
 @end deffn
 
@@ -8591,9 +8608,10 @@ Start-Symbol}.  It cannot be used in the grammar.
 @deffn {Directive} %code @{@var{code}@}
 Other than semantic actions, this is probably the most common place you should
 write verbatim code for the parser implementation.
-For C/C++, it replaces the traditional Yacc prologue,
+It replaces the traditional Yacc prologue,
+@comment For C/C++, it replaces the traditional Yacc prologue,
 @code{%@{@var{code}%@}}, for most purposes.
-For Java, it inserts code into the parser class.
+@comment For Java, it inserts code into the parser class.
 
 @cindex Prologue
 @findex %union
@@ -8607,11 +8625,17 @@ not depend on its position in the grammar file relative to any
 Specifically, @code{%code @{@var{code}@}} always inserts your @var{code} into
 the parser code file after the usual contents of the parser header file.
 
+(Like all the Yacc prologue alternative directives, this directive is
+experimental.
+More user feedback will help to determine whether it should become a permanent
+feature.)
+
 @xref{Prologue Alternatives}.
 @end deffn
 
 @deffn {Directive} %code-top @{@var{code}@}
-Occasionally for C/C++ it is desirable to insert code near the top of the
+Occasionally it is desirable to insert code near the top of the
+@comment Occasionally for C/C++ it is desirable to insert code near the top of the
 parser code file.
 For example:
 
@@ -8622,8 +8646,8 @@ For example:
 @}
 @end smallexample
 
-@noindent
+@comment @noindent
-For Java, @code{%code-top @{@var{code}@}} is currently unused.
+@comment For Java, @code{%code-top @{@var{code}@}} is currently unused.
 
 @cindex Prologue
 @findex %union
@@ -8633,6 +8657,11 @@ Compare with @code{%@{@var{code}%@}} appearing before the first
 on its position in the grammar file relative to any
 @code{%union @{@var{code}@}}.
 
+(Like all the Yacc prologue alternative directives, this directive is
+experimental.
+More user feedback will help to determine whether it should become a permanent
+feature.)
+
 @xref{Prologue Alternatives}.
 @end deffn
 
@@ -8767,11 +8796,17 @@ Bison declaration to assign a precedence to a specific rule.
 @deffn {Directive} %provides @{@var{code}@}
 This is the right place to write additional definitions you would like Bison to
 expose externally.
-For C/C++, this directive inserts your @var{code} both into the parser header
+That is, this directive inserts your @var{code} both into the parser header
+@comment For C/C++, this directive inserts your @var{code} both into the parser header
 file (if generated; @pxref{Table of Symbols, ,%defines}) and into the parser
 code file after Bison's required definitions.
-For Java, it inserts your @var{code} into the parser java file after the parser
+@comment For Java, it inserts your @var{code} into the parser java file after the parser
-class.
+@comment class.
+
+(Like all the Yacc prologue alternative directives, this directive is
+experimental.
+More user feedback will help to determine whether it should become a permanent
+feature.)
 
 @xref{Prologue Alternatives}.
 @end deffn
@@ -8789,12 +8824,13 @@ Require a Version of Bison}.
 @deffn {Directive} %requires @{@var{code}@}
 This is the right place to write dependency code for externally exposed
 definitions required by Bison.
-For C/C++, such exposed definitions are those usually appearing in the parser
+Such exposed definitions are those usually appearing in the parser
+@comment For C/C++, such exposed definitions are those usually appearing in the parser
 header file.
 Thus, this is the right place to define types referenced in
 @code{%union @{@var{code}@}} directives, and it is the right place to override
 Bison's default @code{YYSTYPE} and @code{YYLTYPE} definitions.
-For Java, this is the right place to write import directives.
+@comment For Java, this is the right place to write import directives.
 
 @cindex Prologue
 @findex %union
@@ -8806,6 +8842,11 @@ Unlike @code{%@{@var{code}%@}}, @code{%requires @{@var{code}@}} inserts your
 generated; @pxref{Table of Symbols, ,%defines}) since Bison's required
 definitions should depend on it in both places.
 
+(Like all the Yacc prologue alternative directives, this directive is
+experimental.
+More user feedback will help to determine whether it should become a permanent
+feature.)
+
 @xref{Prologue Alternatives}.
 @end deffn