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Document Yacc prologue alternatives and default %destructor's and

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%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).
This commit is contained in:
Joel E. Denny
2006-12-05 23:13:41 +00:00
parent 02975b9aad
commit 8589431355
3 changed files with 105 additions and 41 deletions
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61
doc/bison.texinfo
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@@ -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
For Java, @code{%code-top @{@var{code}@}} is currently unused.
@comment @noindent
@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
class.
@comment For Java, it inserts your @var{code} into the parser java file after the parser
@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