@value{UPDATED}), the @acronym{GNU} parser generator.
Copyright @copyright{} 1988, 1989, 1990, 1991, 1992, 1993, 1995, 1998,
-1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
+1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008 Free Software
+Foundation, Inc.
@quotation
Permission is granted to copy, distribute and/or modify this document
(a) below. A copy of the license is included in the section entitled
``@acronym{GNU} Free Documentation License.''
-(a) The @acronym{FSF}'s Back-Cover Text is: ``You have freedom to copy
-and modify this @acronym{GNU} Manual, like @acronym{GNU} software.
-Copies published by the Free Software Foundation raise funds for
-@acronym{GNU} development.''
+(a) The FSF's Back-Cover Text is: ``You have the freedom to copy and
+modify this @acronym{GNU} manual. Buying copies from the @acronym{FSF}
+supports it in developing @acronym{GNU} and promoting software
+freedom.''
@end quotation
@end copying
* Expect Decl:: Suppressing warnings about parsing conflicts.
* Start Decl:: Specifying the start symbol.
* Pure Decl:: Requesting a reentrant parser.
+* Push Decl:: Requesting a push parser.
* Decl Summary:: Table of all Bison declarations.
Parser C-Language Interface
* Expect Decl:: Suppressing warnings about parsing conflicts.
* Start Decl:: Specifying the start symbol.
* Pure Decl:: Requesting a reentrant parser.
+* Push Decl:: Requesting a push parser.
* Decl Summary:: Table of all Bison declarations.
@end menu
Precedence}.
You can explicitly specify the numeric code for a token type by appending
-a decimal or hexadecimal integer value in the field immediately
+a nonnegative decimal or hexadecimal integer value in the field immediately
following the token name:
@example
interchangeably in further declarations or the grammar rules. The
@code{yylex} function can use the token name or the literal string to
obtain the token type code number (@pxref{Calling Convention}).
+Syntax error messages passed to @code{yyerror} from the parser will reference
+the literal string instead of the token name.
+
+The token numbered as 0 corresponds to end of file; the following line
+allows for nicer error messages referring to ``end of file'' instead
+of ``$end'':
+
+@example
+%token END 0 "end of file"
+@end example
@node Precedence Decl
@subsection Operator Precedence
@xref{Precedence, ,Operator Precedence}, for general information on
operator precedence.
-The syntax of a precedence declaration is the same as that of
+The syntax of a precedence declaration is nearly the same as that of
@code{%token}: either
@example
the one declared later has the higher precedence and is grouped first.
@end itemize
+For backward compatibility, there is a confusing difference between the
+argument lists of @code{%token} and precedence declarations.
+Only a @code{%token} can associate a literal string with a token type name.
+A precedence declaration always interprets a literal string as a reference to a
+separate token.
+For example:
+
+@example
+%left OR "<=" // Does not declare an alias.
+%left OR 134 "<=" 135 // Declares 134 for OR and 135 for "<=".
+@end example
+
@node Union Decl
@subsection The Collection of Value Types
@cindex declaring value types
@subsection A Pure (Reentrant) Parser
@cindex reentrant parser
@cindex pure parser
-@findex %pure-parser
+@findex %define api.pure
A @dfn{reentrant} program is one which does not alter in the course of
execution; in other words, it consists entirely of @dfn{pure} (read-only)
including @code{yylval} and @code{yylloc}.)
Alternatively, you can generate a pure, reentrant parser. The Bison
-declaration @code{%pure-parser} says that you want the parser to be
+declaration @code{%define api.pure} says that you want the parser to be
reentrant. It looks like this:
@example
-%pure-parser
+%define api.pure
@end example
The result is that the communication variables @code{yylval} and
@code{yylloc} become local variables in @code{yyparse}, and a different
calling convention is used for the lexical analyzer function
@code{yylex}. @xref{Pure Calling, ,Calling Conventions for Pure
-Parsers}, for the details of this. The variable @code{yynerrs} also
-becomes local in @code{yyparse} (@pxref{Error Reporting, ,The Error
+Parsers}, for the details of this. The variable @code{yynerrs}
+becomes local in @code{yyparse} in pull mode but it becomes a member
+of yypstate in push mode. (@pxref{Error Reporting, ,The Error
Reporting Function @code{yyerror}}). The convention for calling
@code{yyparse} itself is unchanged.
You can generate either a pure parser or a nonreentrant parser from any
valid grammar.
+@node Push Decl
+@subsection A Push Parser
+@cindex push parser
+@cindex push parser
+@findex %define api.push_pull
+
+(The current push parsing interface is experimental and may evolve.
+More user feedback will help to stabilize it.)
+
+A pull parser is called once and it takes control until all its input
+is completely parsed. A push parser, on the other hand, is called
+each time a new token is made available.
+
+A push parser is typically useful when the parser is part of a
+main event loop in the client's application. This is typically
+a requirement of a GUI, when the main event loop needs to be triggered
+within a certain time period.
+
+Normally, Bison generates a pull parser.
+The following Bison declaration says that you want the parser to be a push
+parser (@pxref{Decl Summary,,%define api.push_pull}):
+
+@example
+%define api.push_pull "push"
+@end example
+
+In almost all cases, you want to ensure that your push parser is also
+a pure parser (@pxref{Pure Decl, ,A Pure (Reentrant) Parser}). The only
+time you should create an impure push parser is to have backwards
+compatibility with the impure Yacc pull mode interface. Unless you know
+what you are doing, your declarations should look like this:
+
+@example
+%define api.pure
+%define api.push_pull "push"
+@end example
+
+There is a major notable functional difference between the pure push parser
+and the impure push parser. It is acceptable for a pure push parser to have
+many parser instances, of the same type of parser, in memory at the same time.
+An impure push parser should only use one parser at a time.
+
+When a push parser is selected, Bison will generate some new symbols in
+the generated parser. @code{yypstate} is a structure that the generated
+parser uses to store the parser's state. @code{yypstate_new} is the
+function that will create a new parser instance. @code{yypstate_delete}
+will free the resources associated with the corresponding parser instance.
+Finally, @code{yypush_parse} is the function that should be called whenever a
+token is available to provide the parser. A trivial example
+of using a pure push parser would look like this:
+
+@example
+int status;
+yypstate *ps = yypstate_new ();
+do @{
+ status = yypush_parse (ps, yylex (), NULL);
+@} while (status == YYPUSH_MORE);
+yypstate_delete (ps);
+@end example
+
+If the user decided to use an impure push parser, a few things about
+the generated parser will change. The @code{yychar} variable becomes
+a global variable instead of a variable in the @code{yypush_parse} function.
+For this reason, the signature of the @code{yypush_parse} function is
+changed to remove the token as a parameter. A nonreentrant push parser
+example would thus look like this:
+
+@example
+extern int yychar;
+int status;
+yypstate *ps = yypstate_new ();
+do @{
+ yychar = yylex ();
+ status = yypush_parse (ps);
+@} while (status == YYPUSH_MORE);
+yypstate_delete (ps);
+@end example
+
+That's it. Notice the next token is put into the global variable @code{yychar}
+for use by the next invocation of the @code{yypush_parse} function.
+
+Bison also supports both the push parser interface along with the pull parser
+interface in the same generated parser. In order to get this functionality,
+you should replace the @code{%define api.push_pull "push"} declaration with the
+@code{%define api.push_pull "both"} declaration. Doing this will create all of
+the symbols mentioned earlier along with the two extra symbols, @code{yyparse}
+and @code{yypull_parse}. @code{yyparse} can be used exactly as it normally
+would be used. However, the user should note that it is implemented in the
+generated parser by calling @code{yypull_parse}.
+This makes the @code{yyparse} function that is generated with the
+@code{%define api.push_pull "both"} declaration slower than the normal
+@code{yyparse} function. If the user
+calls the @code{yypull_parse} function it will parse the rest of the input
+stream. It is possible to @code{yypush_parse} tokens to select a subgrammar
+and then @code{yypull_parse} the rest of the input stream. If you would like
+to switch back and forth between between parsing styles, you would have to
+write your own @code{yypull_parse} function that knows when to quit looking
+for input. An example of using the @code{yypull_parse} function would look
+like this:
+
+@example
+yypstate *ps = yypstate_new ();
+yypull_parse (ps); /* Will call the lexer */
+yypstate_delete (ps);
+@end example
+
+Adding the @code{%define api.pure} declaration does exactly the same thing to
+the generated parser with @code{%define api.push_pull "both"} as it did for
+@code{%define api.push_pull "push"}.
+
@node Decl Summary
@subsection Bison Declaration Summary
@cindex Bison declaration summary
Not all values of @var{qualifier} are available for all target languages:
@itemize @bullet
-@findex %code requires
@item requires
+@findex %code requires
@itemize @bullet
@item Language(s): C, C++
Omitting @code{"@var{value}"} is always equivalent to specifying it as
@code{""}.
-Some @var{variable}s may be used as booleans.
+Some @var{variable}s may be used as Booleans.
In this case, Bison will complain if the variable definition does not meet one
of the following four conditions:
In this case, Bison selects a default value, which may depend on the selected
target language and/or parser skeleton.
@end enumerate
+
+Some of the accepted @var{variable}s are:
+
+@itemize @bullet
+@item api.pure
+@findex %define api.pure
+
+@itemize @bullet
+@item Language(s): C
+
+@item Purpose: Request a pure (reentrant) parser program.
+@xref{Pure Decl, ,A Pure (Reentrant) Parser}.
+
+@item Accepted Values: Boolean
+
+@item Default Value: @code{"false"}
+@end itemize
+
+@item api.push_pull
+@findex %define api.push_pull
+
+@itemize @bullet
+@item Language(s): C (LALR(1) only)
+
+@item Purpose: Requests a pull parser, a push parser, or both.
+@xref{Push Decl, ,A Push Parser}.
+(The current push parsing interface is experimental and may evolve.
+More user feedback will help to stabilize it.)
+
+@item Accepted Values: @code{"pull"}, @code{"push"}, @code{"both"}
+
+@item Default Value: @code{"pull"}
+@end itemize
+
+@item lr.keep_unreachable_states
+@findex %define lr.keep_unreachable_states
+
+@itemize @bullet
+@item Language(s): all
+
+@item Purpose: Requests that Bison allow unreachable parser states to remain in
+the parser tables.
+Bison considers a state to be unreachable if there exists no sequence of
+transitions from the start state to that state.
+A state can become unreachable during conflict resolution if Bison disables a
+shift action leading to it from a predecessor state.
+Keeping unreachable states is sometimes useful for analysis purposes, but they
+are useless in the generated parser.
+
+@item Accepted Values: Boolean
+
+@item Default Value: @code{"false"}
+
+@item Caveats:
+
+@itemize @bullet
+
+@item Unreachable states may contain conflicts and may use rules not used in
+any other state.
+Thus, keeping unreachable states may induce warnings that are irrelevant to
+your parser's behavior, and it may eliminate warnings that are relevant.
+Of course, the change in warnings may actually be relevant to a parser table
+analysis that wants to keep unreachable states, so this behavior will likely
+remain in future Bison releases.
+
+@item While Bison is able to remove unreachable states, it is not guaranteed to
+remove other kinds of useless states.
+Specifically, when Bison disables reduce actions during conflict resolution,
+some goto actions may become useless, and thus some additional states may
+become useless.
+If Bison were to compute which goto actions were useless and then disable those
+actions, it could identify such states as unreachable and then remove those
+states.
+However, Bison does not compute which goto actions are useless.
+@end itemize
+@end itemize
+
+@item namespace
+@findex %define namespace
+
+@itemize
+@item Languages(s): C++
+
+@item Purpose: Specifies the namespace for the parser class.
+For example, if you specify:
+
+@smallexample
+%define namespace "foo::bar"
+@end smallexample
+
+Bison uses @code{foo::bar} verbatim in references such as:
+
+@smallexample
+foo::bar::parser::semantic_type
+@end smallexample
+
+However, to open a namespace, Bison removes any leading @code{::} and then
+splits on any remaining occurrences:
+
+@smallexample
+namespace foo @{ namespace bar @{
+ class position;
+ class location;
+@} @}
+@end smallexample
+
+@item Accepted Values: Any absolute or relative C++ namespace reference without
+a trailing @code{"::"}.
+For example, @code{"foo"} or @code{"::foo::bar"}.
+
+@item Default Value: The value specified by @code{%name-prefix}, which defaults
+to @code{yy}.
+This usage of @code{%name-prefix} is for backward compatibility and can be
+confusing since @code{%name-prefix} also specifies the textual prefix for the
+lexical analyzer function.
+Thus, if you specify @code{%name-prefix}, it is best to also specify
+@code{%define namespace} so that @code{%name-prefix} @emph{only} affects the
+lexical analyzer function.
+For example, if you specify:
+
+@smallexample
+%define namespace "foo"
+%name-prefix "bar::"
+@end smallexample
+
+The parser namespace is @code{foo} and @code{yylex} is referenced as
+@code{bar::lex}.
+@end itemize
+@end itemize
+
@end deffn
@deffn {Directive} %defines
@deffn {Directive} %language "@var{language}"
Specify the programming language for the generated parser. Currently
-supported languages include C and C++.
+supported languages include C, C++, and Java.
@var{language} is case-insensitive.
@end deffn
in C parsers
is @code{yyparse}, @code{yylex}, @code{yyerror}, @code{yynerrs},
@code{yylval}, @code{yychar}, @code{yydebug}, and
-(if locations are used) @code{yylloc}. For example, if you use
-@samp{%name-prefix "c_"}, the names become @code{c_parse}, @code{c_lex},
-and so on. In C++ parsers, it is only the surrounding namespace which is
-named @var{prefix} instead of @samp{yy}.
+(if locations are used) @code{yylloc}. If you use a push parser,
+@code{yypush_parse}, @code{yypull_parse}, @code{yypstate},
+@code{yypstate_new} and @code{yypstate_delete} will
+also be renamed. For example, if you use @samp{%name-prefix "c_"}, the
+names become @code{c_parse}, @code{c_lex}, and so on.
+For C++ parsers, see the @code{%define namespace} documentation in this
+section.
@xref{Multiple Parsers, ,Multiple Parsers in the Same Program}.
@end deffn
@end deffn
@deffn {Directive} %pure-parser
-Request a pure (reentrant) parser program (@pxref{Pure Decl, ,A Pure
-(Reentrant) Parser}).
+Deprecated version of @code{%define api.pure} (@pxref{Decl Summary, ,%define}),
+for which Bison is more careful to warn about unreasonable usage.
@end deffn
@deffn {Directive} %require "@var{version}"
The precise list of symbols renamed is @code{yyparse}, @code{yylex},
@code{yyerror}, @code{yynerrs}, @code{yylval}, @code{yylloc},
-@code{yychar} and @code{yydebug}. For example, if you use @samp{-p c},
-the names become @code{cparse}, @code{clex}, and so on.
+@code{yychar} and @code{yydebug}. If you use a push parser,
+@code{yypush_parse}, @code{yypull_parse}, @code{yypstate},
+@code{yypstate_new} and @code{yypstate_delete} will also be renamed.
+For example, if you use @samp{-p c}, the names become @code{cparse},
+@code{clex}, and so on.
@strong{All the other variables and macros associated with Bison are not
renamed.} These others are not global; there is no conflict if the same
@menu
* Parser Function:: How to call @code{yyparse} and what it returns.
+* Push Parser Function:: How to call @code{yypush_parse} and what it returns.
+* Pull Parser Function:: How to call @code{yypull_parse} and what it returns.
+* Parser Create Function:: How to call @code{yypstate_new} and what it
+ returns.
+* Parser Delete Function:: How to call @code{yypstate_delete} and what it
+ returns.
* Lexical:: You must supply a function @code{yylex}
which reads tokens.
* Error Reporting:: You must supply a function @code{yyerror}.
exp: @dots{} @{ @dots{}; *randomness += 1; @dots{} @}
@end example
+@node Push Parser Function
+@section The Push Parser Function @code{yypush_parse}
+@findex yypush_parse
+
+(The current push parsing interface is experimental and may evolve.
+More user feedback will help to stabilize it.)
+
+You call the function @code{yypush_parse} to parse a single token. This
+function is available if either the @code{%define api.push_pull "push"} or
+@code{%define api.push_pull "both"} declaration is used.
+@xref{Push Decl, ,A Push Parser}.
+
+@deftypefun int yypush_parse (yypstate *yyps)
+The value returned by @code{yypush_parse} is the same as for yyparse with the
+following exception. @code{yypush_parse} will return YYPUSH_MORE if more input
+is required to finish parsing the grammar.
+@end deftypefun
+
+@node Pull Parser Function
+@section The Pull Parser Function @code{yypull_parse}
+@findex yypull_parse
+
+(The current push parsing interface is experimental and may evolve.
+More user feedback will help to stabilize it.)
+
+You call the function @code{yypull_parse} to parse the rest of the input
+stream. This function is available if the @code{%define api.push_pull "both"}
+declaration is used.
+@xref{Push Decl, ,A Push Parser}.
+
+@deftypefun int yypull_parse (yypstate *yyps)
+The value returned by @code{yypull_parse} is the same as for @code{yyparse}.
+@end deftypefun
+
+@node Parser Create Function
+@section The Parser Create Function @code{yystate_new}
+@findex yypstate_new
+
+(The current push parsing interface is experimental and may evolve.
+More user feedback will help to stabilize it.)
+
+You call the function @code{yypstate_new} to create a new parser instance.
+This function is available if either the @code{%define api.push_pull "push"} or
+@code{%define api.push_pull "both"} declaration is used.
+@xref{Push Decl, ,A Push Parser}.
+
+@deftypefun yypstate *yypstate_new (void)
+The fuction will return a valid parser instance if there was memory available
+or 0 if no memory was available.
+In impure mode, it will also return 0 if a parser instance is currently
+allocated.
+@end deftypefun
+
+@node Parser Delete Function
+@section The Parser Delete Function @code{yystate_delete}
+@findex yypstate_delete
+
+(The current push parsing interface is experimental and may evolve.
+More user feedback will help to stabilize it.)
+
+You call the function @code{yypstate_delete} to delete a parser instance.
+function is available if either the @code{%define api.push_pull "push"} or
+@code{%define api.push_pull "both"} declaration is used.
+@xref{Push Decl, ,A Push Parser}.
+
+@deftypefun void yypstate_delete (yypstate *yyps)
+This function will reclaim the memory associated with a parser instance.
+After this call, you should no longer attempt to use the parser instance.
+@end deftypefun
@node Lexical
@section The Lexical Analyzer Function @code{yylex}
@node Pure Calling
@subsection Calling Conventions for Pure Parsers
-When you use the Bison declaration @code{%pure-parser} to request a
+When you use the Bison declaration @code{%define api.pure} to request a
pure, reentrant parser, the global communication variables @code{yylval}
and @code{yylloc} cannot be used. (@xref{Pure Decl, ,A Pure (Reentrant)
Parser}.) In such parsers the two global variables are replaced by
int yyparse (int *nastiness, int *randomness);
@end example
-If @code{%pure-parser} is added:
+If @code{%define api.pure} is added:
@example
int yylex (YYSTYPE *lvalp, int *nastiness);
@end example
@noindent
-and finally, if both @code{%pure-parser} and @code{%locations} are used:
+and finally, if both @code{%define api.pure} and @code{%locations} are used:
@example
int yylex (YYSTYPE *lvalp, YYLTYPE *llocp, int *nastiness);
an access to the current location.
This is indeed the case for the @acronym{GLR}
parsers, but not for the Yacc parser, for historical reasons. I.e., if
-@samp{%locations %pure-parser} is passed then the prototypes for
+@samp{%locations %define api.pure} is passed then the prototypes for
@code{yyerror} are:
@example
Finally, @acronym{GLR} and Yacc parsers share the same @code{yyerror} calling
convention for absolutely pure parsers, i.e., when the calling
convention of @code{yylex} @emph{and} the calling convention of
-@code{%pure-parser} are pure. I.e.:
+@code{%define api.pure} are pure.
+I.e.:
@example
/* Location tracking. */
%locations
/* Pure yylex. */
-%pure-parser
+%define api.pure
%lex-param @{int *nastiness@}
/* Pure yyparse. */
%parse-param @{int *nastiness@}
@command{bison} reports:
@example
-calc.y: warning: 1 useless nonterminal and 1 useless rule
-calc.y:11.1-7: warning: useless nonterminal: useless
-calc.y:11.10-12: warning: useless rule: useless: STR
+calc.y: warning: 1 nonterminal and 1 rule useless in grammar
+calc.y:11.1-7: warning: nonterminal useless in grammar: useless
+calc.y:11.10-12: warning: rule useless in grammar: useless: STR
calc.y: conflicts: 7 shift/reduce
@end example
The next section reports useless tokens, nonterminal and rules. Useless
nonterminals and rules are removed in order to produce a smaller parser,
but useless tokens are preserved, since they might be used by the
-scanner (note the difference between ``useless'' and ``not used''
+scanner (note the difference between ``useless'' and ``unused''
below):
@example
-Useless nonterminals:
+Nonterminals useless in grammar:
useless
-Terminals which are not used:
+Terminals unused in grammar:
STR
-Useless rules:
+Rules useless in grammar:
#6 useless: STR;
@end example
@example
state 8
- exp -> exp . '+' exp [$, '+', '-', '/'] (rule 1)
+ exp -> exp . '+' exp (rule 1)
exp -> exp '+' exp . [$, '+', '-', '/'] (rule 1)
exp -> exp . '-' exp (rule 2)
exp -> exp . '*' exp (rule 3)
@item --print-localedir
Print the name of the directory containing locale-dependent data.
+@item --print-datadir
+Print the name of the directory containing skeletons and XSLT.
+
@item -y
@itemx --yacc
Act more like the traditional Yacc command. This can cause
like @samp{%glr-parser}, Bison might not be Yacc-compatible even if
this option is specified.
+@item -W
+@itemx --warnings
+Output warnings falling in @var{category}. @var{category} can be one
+of:
+@table @code
+@item midrule-values
+Warn about mid-rule values that are set but not used within any of the actions
+of the parent rule.
+For example, warn about unused @code{$2} in:
+
+@example
+exp: '1' @{ $$ = 1; @} '+' exp @{ $$ = $1 + $4; @};
+@end example
+
+Also warn about mid-rule values that are used but not set.
+For example, warn about unset @code{$$} in the mid-rule action in:
+
+@example
+ exp: '1' @{ $1 = 1; @} '+' exp @{ $$ = $2 + $4; @};
+@end example
+
+These warnings are not enabled by default since they sometimes prove to
+be false alarms in existing grammars employing the Yacc constructs
+@code{$0} or @code{$-@var{n}} (where @var{n} is some positive integer).
+
+
+@item yacc
+Incompatibilities with @acronym{POSIX} Yacc.
+
+@item all
+All the warnings.
+@item none
+Turn off all the warnings.
+@item error
+Treat warnings as errors.
+@end table
+
+A category can be turned off by prefixing its name with @samp{no-}. For
+instance, @option{-Wno-syntax} will hide the warnings about unused
+variables.
@end table
@noindent
@itemx --language=@var{language}
Specify the programming language for the generated parser, as if
@code{%language} was specified (@pxref{Decl Summary, , Bison Declaration
-Summary}). Currently supported languages include C and C++.
+Summary}). Currently supported languages include C, C++, and Java.
@var{language} is case-insensitive.
@item --locations
Adjust the output:
@table @option
-@item -d
-@itemx --defines
+@item --defines[=@var{file}]
Pretend that @code{%defines} was specified, i.e., write an extra output
file containing macro definitions for the token type names defined in
the grammar, as well as a few other declarations. @xref{Decl Summary}.
-@item --defines=@var{defines-file}
-Same as above, but save in the file @var{defines-file}.
+@item -d
+This is the same as @code{--defines} except @code{-d} does not accept a
+@var{file} argument since POSIX Yacc requires that @code{-d} can be bundled
+with other short options.
@item -b @var{file-prefix}
@itemx --file-prefix=@var{prefix}
the full set of items for each state, instead of its core only.
@end table
+@item --report-file=@var{file}
+Specify the @var{file} for the verbose description.
+
@item -v
@itemx --verbose
Pretend that @code{%verbose} was specified, i.e., write an extra output
The other output files' names are constructed from @var{file} as
described under the @samp{-v} and @samp{-d} options.
-@item -g
+@item -g[@var{file}]
+@itemx --graph[=@var{file}]
Output a graphical representation of the @acronym{LALR}(1) grammar
automaton computed by Bison, in @uref{http://www.graphviz.org/, Graphviz}
@uref{http://www.graphviz.org/doc/info/lang.html, @acronym{DOT}} format.
-If the grammar file is @file{foo.y}, the output file will
-be @file{foo.dot}.
-
-@item --graph=@var{graph-file}
-The behavior of @var{--graph} is the same than @samp{-g}. The only
-difference is that it has an optional argument which is the name of
-the output graph file.
+@code{@var{file}} is optional.
+If omitted and the grammar file is @file{foo.y}, the output file will be
+@file{foo.dot}.
+
+@item -x[@var{file}]
+@itemx --xml[=@var{file}]
+Output an XML report of the @acronym{LALR}(1) automaton computed by Bison.
+@code{@var{file}} is optional.
+If omitted and the grammar file is @file{foo.y}, the output file will be
+@file{foo.xml}.
+(The current XML schema is experimental and may evolve.
+More user feedback will help to stabilize it.)
@end table
@node Option Cross Key
@multitable {@option{--defines=@var{defines-file}}} {@option{-b @var{file-prefix}XXX}}
@headitem Long Option @tab Short Option
-@item @option{--debug} @tab @option{-t}
-@item @option{--defines=@var{defines-file}} @tab @option{-d}
-@item @option{--file-prefix=@var{prefix}} @tab @option{-b @var{file-prefix}}
-@item @option{--graph=@var{graph-file}} @tab @option{-d}
-@item @option{--help} @tab @option{-h}
-@item @option{--name-prefix=@var{prefix}} @tab @option{-p @var{name-prefix}}
-@item @option{--no-lines} @tab @option{-l}
-@item @option{--output=@var{outfile}} @tab @option{-o @var{outfile}}
-@item @option{--print-localedir} @tab
-@item @option{--token-table} @tab @option{-k}
-@item @option{--verbose} @tab @option{-v}
-@item @option{--version} @tab @option{-V}
-@item @option{--yacc} @tab @option{-y}
+@include cross-options.texi
@end multitable
@node Yacc Library
@option{--language=c++}.
@xref{Decl Summary}.
-When run, @command{bison} will create several
-entities in the @samp{yy} namespace. Use the @samp{%name-prefix}
-directive to change the namespace name, see @ref{Decl Summary}. The
-various classes are generated in the following files:
+When run, @command{bison} will create several entities in the @samp{yy}
+namespace.
+@findex %define namespace
+Use the @samp{%define namespace} directive to change the namespace name, see
+@ref{Decl Summary}.
+The various classes are generated in the following files:
@table @file
@item position.hh
The parser invokes the scanner by calling @code{yylex}. Contrary to C
parsers, C++ parsers are always pure: there is no point in using the
-@code{%pure-parser} directive. Therefore the interface is as follows.
+@code{%define api.pure} directive. Therefore the interface is as follows.
@deftypemethod {parser} {int} yylex (semantic_value_type& @var{yylval}, location_type& @var{yylloc}, @var{type1} @var{arg1}, ...)
Return the next token. Its type is the return value, its semantic
@c - %language "Java"
@c - initial action
+(The current Java interface is experimental and may evolve.
+More user feedback will help to stabilize it.)
+
The Java parser skeletons are selected using a language directive,
@samp{%language "Java"}, or the synonymous command-line option
@option{--language=java}.
The parser class defines an inner class, @code{Location}, that is used
for location tracking. If the parser is pure, it also defines an
-inner interface, @code{Lexer}; see~@ref{Java Scanner Interface} for the
+inner interface, @code{Lexer}; see @ref{Java Scanner Interface} for the
meaning of pure parsers when the Java language is chosen. Other than
-these inner class/interface, and the members described in~@ref{Java
+these inner class/interface, and the members described in @ref{Java
Parser Interface}, all the other members and fields are preceded
with a @code{yy} prefix to avoid clashes with user code.
state of the parser is always local to an instance of the parser class.
Therefore, all Java parsers are ``pure'', and the @code{%pure-parser}
directive does not do anything when used in Java.
+@c FIXME: But a bit farther it is stated that
+@c If @code{%pure-parser} is not specified, the lexer interface
+@c resides in the same class (@code{YYParser}) as the Bison-generated
+@c parser. The fields and methods that are provided to
+@c this end are as follows.
The scanner always resides in a separate class than the parser.
-Still, Java also two possible ways to interface a Bison-generated Java
+Still, there are two possible ways to interface a Bison-generated Java
parser with a scanner, that is, the scanner may reside in a separate file
than the Bison grammar, or in the same file. The interface
to the scanner is similar in the two cases.
specify them with @code{%lex-param}; they are passed before
@code{%parse-param}s to the constructor.
-In the second case, the scanner has to implement interface @code{Lexer},
+In the second case, the scanner has to implement the @code{Lexer} interface,
which is defined within the parser class (e.g., @code{YYParser.Lexer}).
The constructor of the parser object will then accept an object
implementing the interface; @code{%lex-param} is not used in this
@end deftypemethod
@deftypemethod {Lexer} {Object} getLVal ()
-Return respectively the first position of the last token that yylex
-returned, and the first position beyond it.
+Return the semantical value of the last token that yylex returned.
The return type can be changed using @samp{%define "stype"
"@var{class-name}".}
@end deftypemethod
-If @code{%pure-parser} is not specified, the lexer interface
-resides in the same class (@code{YYParser}) as the Bison-generated
-parser. The fields and methods that are provided to
-this end are as follows.
+The lexer interface resides in the same class (@code{YYParser}) as the
+Bison-generated parser.
+The fields and methods that are provided to this end are as follows.
@deftypemethod {YYParser} {void} error (Location @var{l}, String @var{m})
-As explained in @pxref{Java Parser Interface}, this method is defined
+As already explained (@pxref{Java Parser Interface}), this method is defined
by the user to emit an error message. The first parameter is not used
unless location tracking is active. Its type can be changed using
@samp{%define "location_type" "@var{class-name}".}
@display
My parser includes support for an @samp{#include}-like feature, in
which case I run @code{yyparse} from @code{yyparse}. This fails
-although I did specify I needed a @code{%pure-parser}.
+although I did specify @code{%define api.pure}.
@end display
These problems typically come not from Bison itself, but from
@end deffn
@deffn {Directive} %pure-parser
-Bison declaration to request a pure (reentrant) parser.
-@xref{Pure Decl, ,A Pure (Reentrant) Parser}.
+Deprecated version of @code{%define api.pure} (@pxref{Decl Summary, ,%define}),
+for which Bison is more careful to warn about unreasonable usage.
@end deffn
@deffn {Directive} %require "@var{version}"
@deffn {Variable} yynerrs
Global variable which Bison increments each time it reports a syntax error.
-(In a pure parser, it is a local variable within @code{yyparse}.)
+(In a pure parser, it is a local variable within @code{yyparse}. In a
+pure push parser, it is a member of yypstate.)
@xref{Error Reporting, ,The Error Reporting Function @code{yyerror}}.
@end deffn
parsing. @xref{Parser Function, ,The Parser Function @code{yyparse}}.
@end deffn
+@deffn {Function} yypstate_delete
+The function to delete a parser instance, produced by Bison in push mode;
+call this function to delete the memory associated with a parser.
+@xref{Parser Delete Function, ,The Parser Delete Function
+@code{yypstate_delete}}.
+(The current push parsing interface is experimental and may evolve.
+More user feedback will help to stabilize it.)
+@end deffn
+
+@deffn {Function} yypstate_new
+The function to create a parser instance, produced by Bison in push mode;
+call this function to create a new parser.
+@xref{Parser Create Function, ,The Parser Create Function
+@code{yypstate_new}}.
+(The current push parsing interface is experimental and may evolve.
+More user feedback will help to stabilize it.)
+@end deffn
+
+@deffn {Function} yypull_parse
+The parser function produced by Bison in push mode; call this function to
+parse the rest of the input stream.
+@xref{Pull Parser Function, ,The Pull Parser Function
+@code{yypull_parse}}.
+(The current push parsing interface is experimental and may evolve.
+More user feedback will help to stabilize it.)
+@end deffn
+
+@deffn {Function} yypush_parse
+The parser function produced by Bison in push mode; call this function to
+parse a single token. @xref{Push Parser Function, ,The Push Parser Function
+@code{yypush_parse}}.
+(The current push parsing interface is experimental and may evolve.
+More user feedback will help to stabilize it.)
+@end deffn
+
@deffn {Macro} YYPARSE_PARAM
An obsolete macro for specifying the name of a parameter that
@code{yyparse} should accept. The use of this macro is deprecated, and
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