* doc/bison.texinfo (Tracing): `yyprint' shouldn't prepend a

[bison.git] / doc / bison.texinfo

diff --git a/doc/bison.texinfo b/doc/bison.texinfo
index 123c5261a2e3936ee2442b073bc71b1c3bcadeee..f3a5508062d4bd60d638af961915370111f443fb 100644 (file)
--- a/doc/bison.texinfo
+++ b/doc/bison.texinfo
@@ -208,6 +208,7 @@ Bison Declarations
 * Precedence Decl::   Declaring terminals with precedence and associativity.
 * Union Decl::        Declaring the set of all semantic value types.
 * Type Decl::         Declaring the choice of type for a nonterminal symbol.
 * Precedence Decl::   Declaring terminals with precedence and associativity.
 * Union Decl::        Declaring the set of all semantic value types.
 * Type Decl::         Declaring the choice of type for a nonterminal symbol.

+* Destructor Decl::   Declaring how symbols are freed.

 * Expect Decl::       Suppressing warnings about shift/reduce conflicts.
 * Start Decl::        Specifying the start symbol.
 * Pure Decl::         Requesting a reentrant parser.
 * Expect Decl::       Suppressing warnings about shift/reduce conflicts.
 * Start Decl::        Specifying the start symbol.
 * Pure Decl::         Requesting a reentrant parser.


@@ -268,7 +269,6 @@ Invoking Bison
 * Bison Options::     All the options described in detail,
                         in alphabetical order by short options.
 * Option Cross Key::  Alphabetical list of long options.
 * Bison Options::     All the options described in detail,
                         in alphabetical order by short options.
 * Option Cross Key::  Alphabetical list of long options.

-* VMS Invocation::    Bison command syntax on @acronym{VMS}.

 
 Frequently Asked Questions
 
 
 Frequently Asked Questions
 


@@ -412,42 +412,41 @@ more information on this.
 @cindex generalized @acronym{LR} (@acronym{GLR}) parsing
 @cindex ambiguous grammars
 @cindex non-deterministic parsing
 @cindex generalized @acronym{LR} (@acronym{GLR}) parsing
 @cindex ambiguous grammars
 @cindex non-deterministic parsing

-Parsers for @acronym{LALR}(1) grammars are @dfn{deterministic},
-meaning roughly that
-the next grammar rule to apply at any point in the input is uniquely
-determined by the preceding input and a fixed, finite portion (called
-a @dfn{look-ahead}) of the remaining input.
-A context-free grammar can be @dfn{ambiguous}, meaning that
-there are multiple ways to apply the grammar rules to get the some inputs.
-Even unambiguous grammars can be @dfn{non-deterministic}, meaning that no
-fixed look-ahead always suffices to determine the next grammar rule to apply.
-With the proper declarations, Bison is also able to parse these more general
-context-free grammars, using a technique known as @acronym{GLR} parsing (for
-Generalized @acronym{LR}).  Bison's @acronym{GLR} parsers are able to
-handle any context-free
-grammar for which the number of possible parses of any given string
-is finite.
+
+Parsers for @acronym{LALR}(1) grammars are @dfn{deterministic}, meaning
+roughly that the next grammar rule to apply at any point in the input is
+uniquely determined by the preceding input and a fixed, finite portion
+(called a @dfn{look-ahead}) of the remaining input.  A context-free
+grammar can be @dfn{ambiguous}, meaning that there are multiple ways to
+apply the grammar rules to get the some inputs.  Even unambiguous
+grammars can be @dfn{non-deterministic}, meaning that no fixed
+look-ahead always suffices to determine the next grammar rule to apply.
+With the proper declarations, Bison is also able to parse these more
+general context-free grammars, using a technique known as @acronym{GLR}
+parsing (for Generalized @acronym{LR}).  Bison's @acronym{GLR} parsers
+are able to handle any context-free grammar for which the number of
+possible parses of any given string is finite.

 
 @cindex symbols (abstract)
 @cindex token
 @cindex syntactic grouping
 @cindex grouping, syntactic
 
 @cindex symbols (abstract)
 @cindex token
 @cindex syntactic grouping
 @cindex grouping, syntactic

-In the formal grammatical rules for a language, each kind of syntactic unit
-or grouping is named by a @dfn{symbol}.  Those which are built by grouping
-smaller constructs according to grammatical rules are called
+In the formal grammatical rules for a language, each kind of syntactic
+unit or grouping is named by a @dfn{symbol}.  Those which are built by
+grouping smaller constructs according to grammatical rules are called

 @dfn{nonterminal symbols}; those which can't be subdivided are called
 @dfn{terminal symbols} or @dfn{token types}.  We call a piece of input
 corresponding to a single terminal symbol a @dfn{token}, and a piece
 corresponding to a single nonterminal symbol a @dfn{grouping}.
 
 We can use the C language as an example of what symbols, terminal and
 @dfn{nonterminal symbols}; those which can't be subdivided are called
 @dfn{terminal symbols} or @dfn{token types}.  We call a piece of input
 corresponding to a single terminal symbol a @dfn{token}, and a piece
 corresponding to a single nonterminal symbol a @dfn{grouping}.
 
 We can use the C language as an example of what symbols, terminal and

-nonterminal, mean.  The tokens of C are identifiers, constants (numeric and
-string), and the various keywords, arithmetic operators and punctuation
-marks.  So the terminal symbols of a grammar for C include `identifier',
-`number', `string', plus one symbol for each keyword, operator or
-punctuation mark: `if', `return', `const', `static', `int', `char',
-`plus-sign', `open-brace', `close-brace', `comma' and many more.  (These
-tokens can be subdivided into characters, but that is a matter of
+nonterminal, mean.  The tokens of C are identifiers, constants (numeric
+and string), and the various keywords, arithmetic operators and
+punctuation marks.  So the terminal symbols of a grammar for C include
+`identifier', `number', `string', plus one symbol for each keyword,
+operator or punctuation mark: `if', `return', `const', `static', `int',
+`char', `plus-sign', `open-brace', `close-brace', `comma' and many more.
+(These tokens can be subdivided into characters, but that is a matter of

 lexicography, not grammar.)
 
 Here is a simple C function subdivided into tokens:
 lexicography, not grammar.)
 
 Here is a simple C function subdivided into tokens:


@@ -642,28 +641,28 @@ from the values of the two subexpressions.
 @cindex conflicts
 @cindex shift/reduce conflicts
 
 @cindex conflicts
 @cindex shift/reduce conflicts
 

-In some grammars, there will be cases where Bison's standard @acronym{LALR}(1)
-parsing algorithm cannot decide whether to apply a certain grammar rule
-at a given point.  That is, it may not be able to decide (on the basis
-of the input read so far) which of two possible reductions (applications
-of a grammar rule) applies, or whether to apply a reduction or read more
-of the input and apply a reduction later in the input.  These are known
-respectively as @dfn{reduce/reduce} conflicts (@pxref{Reduce/Reduce}),
-and @dfn{shift/reduce} conflicts (@pxref{Shift/Reduce}).
-
-To use a grammar that is not easily modified to be @acronym{LALR}(1), a more
-general parsing algorithm is sometimes necessary.  If you include
+In some grammars, there will be cases where Bison's standard
+@acronym{LALR}(1) parsing algorithm cannot decide whether to apply a
+certain grammar rule at a given point.  That is, it may not be able to
+decide (on the basis of the input read so far) which of two possible
+reductions (applications of a grammar rule) applies, or whether to apply
+a reduction or read more of the input and apply a reduction later in the
+input.  These are known respectively as @dfn{reduce/reduce} conflicts
+(@pxref{Reduce/Reduce}), and @dfn{shift/reduce} conflicts
+(@pxref{Shift/Reduce}).
+
+To use a grammar that is not easily modified to be @acronym{LALR}(1), a
+more general parsing algorithm is sometimes necessary.  If you include

 @code{%glr-parser} among the Bison declarations in your file
 @code{%glr-parser} among the Bison declarations in your file

-(@pxref{Grammar Outline}), the result will be a Generalized
-@acronym{LR} (@acronym{GLR})
-parser.  These parsers handle Bison grammars that contain no unresolved
-conflicts (i.e., after applying precedence declarations) identically to
-@acronym{LALR}(1) parsers.  However, when faced with unresolved
-shift/reduce and reduce/reduce conflicts, @acronym{GLR} parsers use
-the simple expedient of doing
-both, effectively cloning the parser to follow both possibilities.  Each
-of the resulting parsers can again split, so that at any given time,
-there can be any number of possible parses being explored.  The parsers
+(@pxref{Grammar Outline}), the result will be a Generalized @acronym{LR}
+(@acronym{GLR}) parser.  These parsers handle Bison grammars that
+contain no unresolved conflicts (i.e., after applying precedence
+declarations) identically to @acronym{LALR}(1) parsers.  However, when
+faced with unresolved shift/reduce and reduce/reduce conflicts,
+@acronym{GLR} parsers use the simple expedient of doing both,
+effectively cloning the parser to follow both possibilities.  Each of
+the resulting parsers can again split, so that at any given time, there
+can be any number of possible parses being explored.  The parsers

 proceed in lockstep; that is, all of them consume (shift) a given input
 symbol before any of them proceed to the next.  Each of the cloned
 parsers eventually meets one of two possible fates: either it runs into
 proceed in lockstep; that is, all of them consume (shift) a given input
 symbol before any of them proceed to the next.  Each of the cloned
 parsers eventually meets one of two possible fates: either it runs into


@@ -810,6 +809,32 @@ as both an @code{expr} and a @code{decl}, and print
 "x" y z + T <init-declare> x T <cast> y z + = <OR>
 @end example
 
 "x" y z + T <init-declare> x T <cast> y z + = <OR>
 @end example
 

+@sp 1
+
+@cindex @code{incline}
+@cindex @acronym{GLR} parsers and @code{inline}
+Note that the @acronym{GLR} parsers require an ISO C89 compiler.  In
+addition, they use the @code{inline} keyword, which is not C89, but a
+common extension.  It is up to the user of these parsers to handle
+portability issues.  For instance, if using Autoconf and the Autoconf
+macro @code{AC_C_INLINE}, a mere
+
+@example
+%@{
+#include <config.h>
+%@}
+@end example
+
+@noindent
+will suffice.  Otherwise, we suggest
+
+@example
+%@{
+#if ! defined __GNUC__ && ! defined inline
+# define inline
+#endif
+%@}
+@end example

 
 @node Locations Overview
 @section Locations
 
 @node Locations Overview
 @section Locations


@@ -1088,18 +1113,18 @@ input:    /* empty */
 ;
 
 line:     '\n'
 ;
 
 line:     '\n'

-        | exp '\n'  @{ printf ("\t%.10g\n", $1); @}
+        | exp '\n'      @{ printf ("\t%.10g\n", $1); @}

 ;
 
 ;
 

-exp:      NUM             @{ $$ = $1;         @}
-        | exp exp '+'     @{ $$ = $1 + $2;    @}
-        | exp exp '-'     @{ $$ = $1 - $2;    @}
-        | exp exp '*'     @{ $$ = $1 * $2;    @}
-        | exp exp '/'     @{ $$ = $1 / $2;    @}
-      /* Exponentiation */
-        | exp exp '^'     @{ $$ = pow ($1, $2); @}
-      /* Unary minus    */
-        | exp 'n'         @{ $$ = -$1;        @}
+exp:      NUM           @{ $$ = $1;           @}
+        | exp exp '+'   @{ $$ = $1 + $2;      @}
+        | exp exp '-'   @{ $$ = $1 - $2;      @}
+        | exp exp '*'   @{ $$ = $1 * $2;      @}
+        | exp exp '/'   @{ $$ = $1 / $2;      @}
+         /* Exponentiation */
+        | exp exp '^'   @{ $$ = pow ($1, $2); @}
+         /* Unary minus    */
+        | exp 'n'       @{ $$ = -$1;          @}

 ;
 %%
 @end example
 ;
 %%
 @end example


@@ -1348,7 +1373,7 @@ main (void)
 
 When @code{yyparse} detects a syntax error, it calls the error reporting
 function @code{yyerror} to print an error message (usually but not
 
 When @code{yyparse} detects a syntax error, it calls the error reporting
 function @code{yyerror} to print an error message (usually but not

-always @code{"parse error"}).  It is up to the programmer to supply
+always @code{"syntax error"}).  It is up to the programmer to supply

 @code{yyerror} (@pxref{Interface, ,Parser C-Language Interface}), so
 here is the definition we will use:
 
 @code{yyerror} (@pxref{Interface, ,Parser C-Language Interface}), so
 here is the definition we will use:
 


@@ -1558,7 +1583,7 @@ line:     '\n'
 @end example
 
 This addition to the grammar allows for simple error recovery in the
 @end example
 
 This addition to the grammar allows for simple error recovery in the

-event of a parse error.  If an expression that cannot be evaluated is
+event of a syntax error.  If an expression that cannot be evaluated is

 read, the error will be recognized by the third rule for @code{line},
 and parsing will continue.  (The @code{yyerror} function is still called
 upon to print its message as well.)  The action executes the statement
 read, the error will be recognized by the third rule for @code{line},
 and parsing will continue.  (The @code{yyerror} function is still called
 upon to print its message as well.)  The action executes the statement


@@ -1706,11 +1731,15 @@ int
 yylex (void)
 @{
   int c;
 yylex (void)
 @{
   int c;

+@end group

 
 

+@group

   /* Skip white space.  */
   while ((c = getchar ()) == ' ' || c == '\t')
     ++yylloc.last_column;
   /* Skip white space.  */
   while ((c = getchar ()) == ' ' || c == '\t')
     ++yylloc.last_column;

+@end group

 
 

+@group

   /* Step.  */
   yylloc.first_line = yylloc.last_line;
   yylloc.first_column = yylloc.last_column;
   /* Step.  */
   yylloc.first_line = yylloc.last_line;
   yylloc.first_column = yylloc.last_column;


@@ -1832,27 +1861,30 @@ Note that multiple assignment and nested function calls are permitted.
 Here are the C and Bison declarations for the multi-function calculator.
 
 @smallexample
 Here are the C and Bison declarations for the multi-function calculator.
 
 @smallexample

+@group

 %@{
 #include <math.h>  /* For math functions, cos(), sin(), etc.  */
 %@{
 #include <math.h>  /* For math functions, cos(), sin(), etc.  */

-#include "calc.h"  /* Contains definition of `symrec'        */
+#include "calc.h"  /* Contains definition of `symrec'         */

 %@}
 %@}

+@end group
+@group

 %union @{
 %union @{

-double     val;  /* For returning numbers.                   */
-symrec  *tptr;   /* For returning symbol-table pointers      */
+  double    val;   /* For returning numbers.                  */
+  symrec  *tptr;   /* For returning symbol-table pointers.    */

 @}
 @}

-
-%token <val>  NUM        /* Simple double precision number   */
-%token <tptr> VAR FNCT   /* Variable and Function            */
+@end group
+%token <val>  NUM        /* Simple double precision number.   */
+%token <tptr> VAR FNCT   /* Variable and Function.            */

 %type  <val>  exp
 
 %type  <val>  exp
 

+@group

 %right '='
 %left '-' '+'
 %left '*' '/'
 %left NEG     /* Negation--unary minus */
 %right '^'    /* Exponentiation        */
 %right '='
 %left '-' '+'
 %left '*' '/'
 %left NEG     /* Negation--unary minus */
 %right '^'    /* Exponentiation        */

-
+@end group

 /* Grammar follows */
 /* Grammar follows */

-

 %%
 @end smallexample
 
 %%
 @end smallexample
 


@@ -1886,16 +1918,21 @@ Most of them are copied directly from @code{calc}; three rules,
 those which mention @code{VAR} or @code{FNCT}, are new.
 
 @smallexample
 those which mention @code{VAR} or @code{FNCT}, are new.
 
 @smallexample

+@group

 input:   /* empty */
         | input line
 ;
 input:   /* empty */
         | input line
 ;

+@end group

 
 

+@group

 line:
           '\n'
         | exp '\n'   @{ printf ("\t%.10g\n", $1); @}
         | error '\n' @{ yyerrok;                  @}
 ;
 line:
           '\n'
         | exp '\n'   @{ printf ("\t%.10g\n", $1); @}
         | error '\n' @{ yyerrok;                  @}
 ;

+@end group

 
 

+@group

 exp:      NUM                @{ $$ = $1;                         @}
         | VAR                @{ $$ = $1->value.var;              @}
         | VAR '=' exp        @{ $$ = $3; $1->value.var = $3;     @}
 exp:      NUM                @{ $$ = $1;                         @}
         | VAR                @{ $$ = $1->value.var;              @}
         | VAR '=' exp        @{ $$ = $3; $1->value.var = $3;     @}


@@ -1908,6 +1945,7 @@ exp:      NUM                @{ $$ = $1;                         @}
         | exp '^' exp        @{ $$ = pow ($1, $3);               @}
         | '(' exp ')'        @{ $$ = $2;                         @}
 ;
         | exp '^' exp        @{ $$ = pow ($1, $3);               @}
         | '(' exp ')'        @{ $$ = $2;                         @}
 ;

+@end group

 /* End of grammar */
 %%
 @end smallexample
 /* End of grammar */
 %%
 @end smallexample


@@ -1929,7 +1967,9 @@ provides for either functions or variables to be placed in the table.
 @group
 /* Function type.                                    */
 typedef double (*func_t) (double);
 @group
 /* Function type.                                    */
 typedef double (*func_t) (double);

+@end group

 
 

+@group

 /* Data type for links in the chain of symbols.      */
 struct symrec
 @{
 /* Data type for links in the chain of symbols.      */
 struct symrec
 @{


@@ -1960,9 +2000,9 @@ function that initializes the symbol table.  Here it is, and
 @code{init_table} as well:
 
 @smallexample
 @code{init_table} as well:
 
 @smallexample

-@group

 #include <stdio.h>
 
 #include <stdio.h>
 

+@group

 int
 main (void)
 @{
 int
 main (void)
 @{


@@ -1977,7 +2017,9 @@ yyerror (const char *s)  /* Called by yyparse on error.  */
 @{
   printf ("%s\n", s);
 @}
 @{
   printf ("%s\n", s);
 @}

+@end group

 
 

+@group

 struct init
 @{
   char *fname;
 struct init
 @{
   char *fname;


@@ -1996,7 +2038,9 @@ struct init arith_fncts[] =
   "sqrt", sqrt,
   0, 0
 @};
   "sqrt", sqrt,
   0, 0
 @};

+@end group

 
 

+@group

 /* The symbol table: a chain of `struct symrec'.  */
 symrec *sym_table = (symrec *) 0;
 @end group
 /* The symbol table: a chain of `struct symrec'.  */
 symrec *sym_table = (symrec *) 0;
 @end group


@@ -2072,7 +2116,9 @@ operators in @code{yylex}.
 @smallexample
 @group
 #include <ctype.h>
 @smallexample
 @group
 #include <ctype.h>

+@end group

 
 

+@group

 int
 yylex (void)
 @{
 int
 yylex (void)
 @{


@@ -2120,7 +2166,7 @@ yylex (void)
           if (i == length)
             @{
               length *= 2;
           if (i == length)
             @{
               length *= 2;

-              symbuf = (char *)realloc (symbuf, length + 1);
+              symbuf = (char *) realloc (symbuf, length + 1);

             @}
           /* Add this character to the buffer.         */
           symbuf[i++] = c;
             @}
           /* Add this character to the buffer.         */
           symbuf[i++] = c;


@@ -2749,11 +2795,11 @@ a-or-b: 'a'|'b'   @{ a_or_b_found = 1; @};
 
 @cindex default action
 If you don't specify an action for a rule, Bison supplies a default:
 
 @cindex default action
 If you don't specify an action for a rule, Bison supplies a default:

-@w{@code{$$ = $1}.}  Thus, the value of the first symbol in the rule becomes
-the value of the whole rule.  Of course, the default rule is valid only
-if the two data types match.  There is no meaningful default action for
-an empty rule; every empty rule must have an explicit action unless the
-rule's value does not matter.
+@w{@code{$$ = $1}.}  Thus, the value of the first symbol in the rule
+becomes the value of the whole rule.  Of course, the default action is
+valid only if the two data types match.  There is no meaningful default
+action for an empty rule; every empty rule must have an explicit action
+unless the rule's value does not matter.

 
 @code{$@var{n}} with @var{n} zero or negative is allowed for reference
 to tokens and groupings on the stack @emph{before} those that match the
 
 @code{$@var{n}} with @var{n} zero or negative is allowed for reference
 to tokens and groupings on the stack @emph{before} those that match the


@@ -3175,6 +3221,7 @@ Grammars}).
 * Precedence Decl::   Declaring terminals with precedence and associativity.
 * Union Decl::        Declaring the set of all semantic value types.
 * Type Decl::         Declaring the choice of type for a nonterminal symbol.
 * Precedence Decl::   Declaring terminals with precedence and associativity.
 * Union Decl::        Declaring the set of all semantic value types.
 * Type Decl::         Declaring the choice of type for a nonterminal symbol.

+* Destructor Decl::   Declaring how symbols are freed.

 * Expect Decl::       Suppressing warnings about shift/reduce conflicts.
 * Start Decl::        Specifying the start symbol.
 * Pure Decl::         Requesting a reentrant parser.
 * Expect Decl::       Suppressing warnings about shift/reduce conflicts.
 * Start Decl::        Specifying the start symbol.
 * Pure Decl::         Requesting a reentrant parser.


@@ -3365,6 +3412,71 @@ use the same @code{<@var{type}>} construction in a declaration for the
 terminal symbol.  All kinds of token declarations allow
 @code{<@var{type}>}.
 
 terminal symbol.  All kinds of token declarations allow
 @code{<@var{type}>}.
 

+@node Destructor Decl
+@subsection Freeing Discarded Symbols
+@cindex freeing discarded symbols
+@findex %destructor
+
+Some symbols can be discarded by the parser, typically during error
+recovery (@pxref{Error Recovery}).  Basically, during error recovery,
+embarrassing symbols already pushed on the stack, and embarrassing
+tokens coming from the rest of the file are thrown away until the parser
+falls on its feet.  If these symbols convey heap based information, this
+memory is lost.  While this behavior is tolerable for batch parsers,
+such as in compilers, it is unacceptable for parsers that can
+possibility ``never end'' such as shells, or implementations of
+communication protocols.
+
+The @code{%destructor} directive allows for the definition of code that
+is called when a symbol is thrown away.
+
+@deffn {Directive} %destructor @{ @var{code} @} @var{symbols}
+@findex %destructor
+Declare that the @var{code} must be invoked for each of the
+@var{symbols} that will be discarded by the parser.  The @var{code}
+should use @code{$$} to designate the semantic value associated to the
+@var{symbols}.  The additional parser parameters are also avaible
+(@pxref{Parser Function, , The Parser Function @code{yyparse}}).
+
+@strong{Warning:} as of Bison 1.875, this feature is still considered as
+experimental, as there was not enough users feedback.  In particular,
+the syntax might still change.
+@end deffn
+
+For instance:
+
+@smallexample
+%union
+@{
+  char *string;
+@}
+%token <string> STRING
+%type  <string> string
+%destructor @{ free ($$); @} STRING string
+@end smallexample
+
+@noindent
+guarantees that when a @code{STRING} or a @code{string} will be discarded,
+its associated memory will be freed.
+
+Note that in the future, Bison might also consider that right hand side
+members that are not mentioned in the action can be destroyed.  For
+instance, in:
+
+@smallexample
+comment: "/*" STRING "*/";
+@end smallexample
+
+@noindent
+the parser is entitled to destroy the semantic value of the
+@code{string}.  Of course, this will not apply to the default action;
+compare:
+
+@smallexample
+typeless: string;  // $$ = $1 does not apply; $1 is destroyed.
+typefull: string;  // $$ = $1 applies, $1 is not destroyed.
+@end smallexample
+

 @node Expect Decl
 @subsection Suppressing Conflict Warnings
 @cindex suppressing conflict warnings
 @node Expect Decl
 @subsection Suppressing Conflict Warnings
 @cindex suppressing conflict warnings


@@ -3477,53 +3589,60 @@ valid grammar.
 
 Here is a summary of the declarations used to define a grammar:
 
 
 Here is a summary of the declarations used to define a grammar:
 

-@table @code
-@item %union
+@deffn {Directive} %union

 Declare the collection of data types that semantic values may have
 (@pxref{Union Decl, ,The Collection of Value Types}).
 Declare the collection of data types that semantic values may have
 (@pxref{Union Decl, ,The Collection of Value Types}).

+@end deffn

 
 

-@item %token
+@deffn {Directive} %token

 Declare a terminal symbol (token type name) with no precedence
 or associativity specified (@pxref{Token Decl, ,Token Type Names}).
 Declare a terminal symbol (token type name) with no precedence
 or associativity specified (@pxref{Token Decl, ,Token Type Names}).

+@end deffn

 
 

-@item %right
+@deffn {Directive} %right

 Declare a terminal symbol (token type name) that is right-associative
 (@pxref{Precedence Decl, ,Operator Precedence}).
 Declare a terminal symbol (token type name) that is right-associative
 (@pxref{Precedence Decl, ,Operator Precedence}).

+@end deffn

 
 

-@item %left
+@deffn {Directive} %left

 Declare a terminal symbol (token type name) that is left-associative
 (@pxref{Precedence Decl, ,Operator Precedence}).
 Declare a terminal symbol (token type name) that is left-associative
 (@pxref{Precedence Decl, ,Operator Precedence}).

+@end deffn

 
 

-@item %nonassoc
+@deffn {Directive} %nonassoc

 Declare a terminal symbol (token type name) that is nonassociative
 (using it in a way that would be associative is a syntax error)
 Declare a terminal symbol (token type name) that is nonassociative
 (using it in a way that would be associative is a syntax error)

+@end deffn

 (@pxref{Precedence Decl, ,Operator Precedence}).
 
 (@pxref{Precedence Decl, ,Operator Precedence}).
 

-@item %type
+@deffn {Directive} %type

 Declare the type of semantic values for a nonterminal symbol
 (@pxref{Type Decl, ,Nonterminal Symbols}).
 Declare the type of semantic values for a nonterminal symbol
 (@pxref{Type Decl, ,Nonterminal Symbols}).

+@end deffn

 
 

-@item %start
+@deffn {Directive} %start

 Specify the grammar's start symbol (@pxref{Start Decl, ,The
 Start-Symbol}).
 Specify the grammar's start symbol (@pxref{Start Decl, ,The
 Start-Symbol}).

+@end deffn

 
 

-@item %expect
+@deffn {Directive} %expect

 Declare the expected number of shift-reduce conflicts
 (@pxref{Expect Decl, ,Suppressing Conflict Warnings}).
 Declare the expected number of shift-reduce conflicts
 (@pxref{Expect Decl, ,Suppressing Conflict Warnings}).

-@end table
+@end deffn
+

 
 @sp 1
 @noindent
 In order to change the behavior of @command{bison}, use the following
 directives:
 
 
 @sp 1
 @noindent
 In order to change the behavior of @command{bison}, use the following
 directives:
 

-@table @code
-@item %debug
+@deffn {Directive} %debug

 In the parser file, define the macro @code{YYDEBUG} to 1 if it is not
 already defined, so that the debugging facilities are compiled.
 In the parser file, define the macro @code{YYDEBUG} to 1 if it is not
 already defined, so that the debugging facilities are compiled.

+@end deffn

 @xref{Tracing, ,Tracing Your Parser}.
 
 @xref{Tracing, ,Tracing Your Parser}.
 

-@item %defines
+@deffn {Directive} %defines

 Write an extra output file containing macro definitions for the token
 type names defined in the grammar and the semantic value type
 @code{YYSTYPE}, as well as a few @code{extern} variable declarations.
 Write an extra output file containing macro definitions for the token
 type names defined in the grammar and the semantic value type
 @code{YYSTYPE}, as well as a few @code{extern} variable declarations.


@@ -3535,27 +3654,27 @@ This output file is essential if you wish to put the definition of
 @code{yylex} in a separate source file, because @code{yylex} needs to
 be able to refer to token type codes and the variable
 @code{yylval}.  @xref{Token Values, ,Semantic Values of Tokens}.
 @code{yylex} in a separate source file, because @code{yylex} needs to
 be able to refer to token type codes and the variable
 @code{yylval}.  @xref{Token Values, ,Semantic Values of Tokens}.

+@end deffn

 
 

-@item %file-prefix="@var{prefix}"
+@deffn {Directive} %destructor
+Specifying how the parser should reclaim the memory associated to
+discarded symbols. @xref{Destructor Decl, , Freeing Discarded Symbols}.
+@end deffn
+
+@deffn {Directive} %file-prefix="@var{prefix}"

 Specify a prefix to use for all Bison output file names.  The names are
 chosen as if the input file were named @file{@var{prefix}.y}.
 Specify a prefix to use for all Bison output file names.  The names are
 chosen as if the input file were named @file{@var{prefix}.y}.

+@end deffn

 
 

-@c @item %header-extension
-@c Specify the extension of the parser header file generated when
-@c @code{%define} or @samp{-d} are used.
-@c
-@c For example, a grammar file named @file{foo.ypp} and containing a
-@c @code{%header-extension .hh} directive will produce a header file
-@c named @file{foo.tab.hh}
-
-@item %locations
+@deffn {Directive} %locations

 Generate the code processing the locations (@pxref{Action Features,
 ,Special Features for Use in Actions}).  This mode is enabled as soon as
 the grammar uses the special @samp{@@@var{n}} tokens, but if your
 grammar does not use it, using @samp{%locations} allows for more
 Generate the code processing the locations (@pxref{Action Features,
 ,Special Features for Use in Actions}).  This mode is enabled as soon as
 the grammar uses the special @samp{@@@var{n}} tokens, but if your
 grammar does not use it, using @samp{%locations} allows for more

-accurate parse error messages.
+accurate syntax error messages.
+@end deffn

 
 

-@item %name-prefix="@var{prefix}"
+@deffn {Directive} %name-prefix="@var{prefix}"

 Rename the external symbols used in the parser so that they start with
 @var{prefix} instead of @samp{yy}.  The precise list of symbols renamed
 is @code{yyparse}, @code{yylex}, @code{yyerror}, @code{yynerrs},
 Rename the external symbols used in the parser so that they start with
 @var{prefix} instead of @samp{yy}.  The precise list of symbols renamed
 is @code{yyparse}, @code{yylex}, @code{yyerror}, @code{yynerrs},


@@ -3564,8 +3683,9 @@ possible @code{yylloc}.  For example, if you use
 @samp{%name-prefix="c_"}, the names become @code{c_parse}, @code{c_lex},
 and so on.  @xref{Multiple Parsers, ,Multiple Parsers in the Same
 Program}.
 @samp{%name-prefix="c_"}, the names become @code{c_parse}, @code{c_lex},
 and so on.  @xref{Multiple Parsers, ,Multiple Parsers in the Same
 Program}.

+@end deffn

 
 

-@item %no-parser
+@deffn {Directive} %no-parser

 Do not include any C code in the parser file; generate tables only.  The
 parser file contains just @code{#define} directives and static variable
 declarations.
 Do not include any C code in the parser file; generate tables only.  The
 parser file contains just @code{#define} directives and static variable
 declarations.


@@ -3573,30 +3693,27 @@ declarations.
 This option also tells Bison to write the C code for the grammar actions
 into a file named @file{@var{filename}.act}, in the form of a
 brace-surrounded body fit for a @code{switch} statement.
 This option also tells Bison to write the C code for the grammar actions
 into a file named @file{@var{filename}.act}, in the form of a
 brace-surrounded body fit for a @code{switch} statement.

+@end deffn

 
 

-@item %no-lines
+@deffn {Directive} %no-lines

 Don't generate any @code{#line} preprocessor commands in the parser
 file.  Ordinarily Bison writes these commands in the parser file so that
 the C compiler and debuggers will associate errors and object code with
 your source file (the grammar file).  This directive causes them to
 associate errors with the parser file, treating it an independent source
 file in its own right.
 Don't generate any @code{#line} preprocessor commands in the parser
 file.  Ordinarily Bison writes these commands in the parser file so that
 the C compiler and debuggers will associate errors and object code with
 your source file (the grammar file).  This directive causes them to
 associate errors with the parser file, treating it an independent source
 file in its own right.

+@end deffn

 
 

-@item %output="@var{filename}"
+@deffn {Directive} %output="@var{filename}"

 Specify the @var{filename} for the parser file.
 Specify the @var{filename} for the parser file.

+@end deffn

 
 

-@item %pure-parser
+@deffn {Directive} %pure-parser

 Request a pure (reentrant) parser program (@pxref{Pure Decl, ,A Pure
 (Reentrant) Parser}).
 Request a pure (reentrant) parser program (@pxref{Pure Decl, ,A Pure
 (Reentrant) Parser}).

+@end deffn

 
 

-@c @item %source-extension
-@c Specify the extension of the parser output file.
-@c
-@c For example, a grammar file named @file{foo.yy} and containing a
-@c @code{%source-extension .cpp} directive will produce a parser file
-@c named @file{foo.tab.cpp}
-
-@item %token-table
+@deffn {Directive} %token-table

 Generate an array of token names in the parser file.  The name of the
 array is @code{yytname}; @code{yytname[@var{i}]} is the name of the
 token whose internal Bison token code number is @var{i}.  The first
 Generate an array of token names in the parser file.  The name of the
 array is @code{yytname}; @code{yytname[@var{i}]} is the name of the
 token whose internal Bison token code number is @var{i}.  The first


@@ -3628,21 +3745,19 @@ The number of grammar rules,
 @item YYNSTATES
 The number of parser states (@pxref{Parser States}).
 @end table
 @item YYNSTATES
 The number of parser states (@pxref{Parser States}).
 @end table

+@end deffn

 
 

-@item %verbose
+@deffn {Directive} %verbose

 Write an extra output file containing verbose descriptions of the
 parser states and what is done for each type of look-ahead token in
 that state.  @xref{Understanding, , Understanding Your Parser}, for more
 information.
 Write an extra output file containing verbose descriptions of the
 parser states and what is done for each type of look-ahead token in
 that state.  @xref{Understanding, , Understanding Your Parser}, for more
 information.

+@end deffn

 
 

-
-
-@item %yacc
+@deffn {Directive} %yacc

 Pretend the option @option{--yacc} was given, i.e., imitate Yacc,
 including its naming conventions.  @xref{Bison Options}, for more.
 Pretend the option @option{--yacc} was given, i.e., imitate Yacc,
 including its naming conventions.  @xref{Bison Options}, for more.

-@end table
-
-
+@end deffn

 
 
 @node Multiple Parsers
 
 
 @node Multiple Parsers


@@ -3732,7 +3847,7 @@ If you use a reentrant parser, you can optionally pass additional
 parameter information to it in a reentrant way.  To do so, use the
 declaration @code{%parse-param}:
 
 parameter information to it in a reentrant way.  To do so, use the
 declaration @code{%parse-param}:
 

-@deffn {Directive} %parse-param @var{argument-declaration} @var{argument-name}
+@deffn {Directive} %parse-param @{@var{argument-declaration}@}, @{@var{argument-name}@}

 @findex %parse-param
 Declare that @code{argument-name} is an additional @code{yyparse}
 argument.  This argument is also passed to @code{yyerror}.  The
 @findex %parse-param
 Declare that @code{argument-name} is an additional @code{yyparse}
 argument.  This argument is also passed to @code{yyerror}.  The


@@ -3743,8 +3858,8 @@ prototypes.
 Here's an example.  Write this in the parser:
 
 @example
 Here's an example.  Write this in the parser:
 
 @example

-%parse-param "int *nastiness"  "nastiness"
-%parse-param "int *randomness" "randomness"
+%parse-param @{int *nastiness@},  @{nastiness@}
+%parse-param @{int *randomness@}, @{randomness@}

 @end example
 
 @noindent
 @end example
 
 @noindent


@@ -3975,7 +4090,7 @@ If you wish to pass the additional parameter data to @code{yylex}, use
 @code{%lex-param} just like @code{%parse-param} (@pxref{Parser
 Function}).
 
 @code{%lex-param} just like @code{%parse-param} (@pxref{Parser
 Function}).
 

-@deffn {Directive} lex-param @var{argument-declaration} @var{argument-name}
+@deffn {Directive} lex-param @{@var{argument-declaration}@}, @{@var{argument-name}@}

 @findex %lex-param
 Declare that @code{argument-name} is an additional @code{yylex}
 argument.
 @findex %lex-param
 Declare that @code{argument-name} is an additional @code{yylex}
 argument.


@@ -3984,9 +4099,9 @@ argument.
 For instance:
 
 @example
 For instance:
 
 @example

-%parse-param "int *nastiness"  "nastiness"
-%lex-param   "int *nastiness"  "nastiness"
-%parse-param "int *randomness" "randomness"
+%parse-param @{int *nastiness@},  @{nastiness@}
+%lex-param   @{int *nastiness@},  @{nastiness@}
+%parse-param @{int *randomness@}, @{randomness@}

 @end example
 
 @noindent
 @end example
 
 @noindent


@@ -4019,7 +4134,7 @@ int yyparse (int *nastiness, int *randomness);
 @cindex parse error
 @cindex syntax error
 
 @cindex parse error
 @cindex syntax error
 

-The Bison parser detects a @dfn{parse error} or @dfn{syntax error}
+The Bison parser detects a @dfn{syntax error} or @dfn{parse error}

 whenever it reads a token which cannot satisfy any syntax rule.  An
 action in the grammar can also explicitly proclaim an error, using the
 macro @code{YYERROR} (@pxref{Action Features, ,Special Features for Use
 whenever it reads a token which cannot satisfy any syntax rule.  An
 action in the grammar can also explicitly proclaim an error, using the
 macro @code{YYERROR} (@pxref{Action Features, ,Special Features for Use


@@ -4028,14 +4143,14 @@ in Actions}).
 The Bison parser expects to report the error by calling an error
 reporting function named @code{yyerror}, which you must supply.  It is
 called by @code{yyparse} whenever a syntax error is found, and it
 The Bison parser expects to report the error by calling an error
 reporting function named @code{yyerror}, which you must supply.  It is
 called by @code{yyparse} whenever a syntax error is found, and it

-receives one argument.  For a parse error, the string is normally
-@w{@code{"parse error"}}.
+receives one argument.  For a syntax error, the string is normally
+@w{@code{"syntax error"}}.

 
 @findex %error-verbose
 If you invoke the directive @code{%error-verbose} in the Bison
 declarations section (@pxref{Bison Declarations, ,The Bison Declarations
 Section}), then Bison provides a more verbose and specific error message
 
 @findex %error-verbose
 If you invoke the directive @code{%error-verbose} in the Bison
 declarations section (@pxref{Bison Declarations, ,The Bison Declarations
 Section}), then Bison provides a more verbose and specific error message

-string instead of just plain @w{@code{"parse error"}}.
+string instead of just plain @w{@code{"syntax error"}}.

 
 The parser can detect one other kind of error: stack overflow.  This
 happens when the input contains constructions that are very deeply
 
 The parser can detect one other kind of error: stack overflow.  This
 happens when the input contains constructions that are very deeply


@@ -4075,7 +4190,7 @@ void yyerror (const char *msg);                 /* Yacc parsers.  */
 void yyerror (YYLTYPE *locp, const char *msg);  /* GLR parsers.   */
 @end example
 
 void yyerror (YYLTYPE *locp, const char *msg);  /* GLR parsers.   */
 @end example
 

-If @samp{%parse-param "int *nastiness"  "nastiness"} is used, then:
+If @samp{%parse-param @{int *nastiness@}, @{nastiness@}} is used, then:

 
 @example
 void yyerror (int *randomness, const char *msg);  /* Yacc parsers.  */
 
 @example
 void yyerror (int *randomness, const char *msg);  /* Yacc parsers.  */


@@ -4092,10 +4207,10 @@ convention of @code{yylex} @emph{and} the calling convention of
 %locations
 /* Pure yylex.  */
 %pure-parser
 %locations
 /* Pure yylex.  */
 %pure-parser

-%lex-param   "int *nastiness"  "nastiness"
+%lex-param   @{int *nastiness@},  @{nastiness@}

 /* Pure yyparse.  */
 /* Pure yyparse.  */

-%parse-param "int *nastiness"  "nastiness"
-%parse-param "int *randomness" "randomness"
+%parse-param @{int *nastiness@},  @{nastiness@}
+%parse-param @{int *randomness@}, @{randomness@}

 @end example
 
 @noindent
 @end example
 
 @noindent


@@ -4109,12 +4224,11 @@ void yyerror (YYLTYPE *locp,
               const char *msg);
 @end example
 
               const char *msg);
 @end example
 

-@noident
+@noindent

 Please, note that the prototypes are only indications of how the code
 Please, note that the prototypes are only indications of how the code

-produced by Bison will use @code{yyerror}, but you still have freedom
-and the exit value, and even on making @code{yyerror} a variadic
-function.  It is precisely to enable this that the message is passed
-last.
+produced by Bison will use @code{yyerror}; you still have freedom on the
+exit value, and even on making @code{yyerror} a variadic function.  It
+is precisely to enable this that the message is always passed last.

 
 @vindex yynerrs
 The variable @code{yynerrs} contains the number of syntax errors
 
 @vindex yynerrs
 The variable @code{yynerrs} contains the number of syntax errors


@@ -4130,34 +4244,39 @@ then it is a local variable which only the actions can access.
 Here is a table of Bison constructs, variables and macros that
 are useful in actions.
 
 Here is a table of Bison constructs, variables and macros that
 are useful in actions.
 

-@table @samp
-@item $$
+@deffn {Variable} $$

 Acts like a variable that contains the semantic value for the
 grouping made by the current rule.  @xref{Actions}.
 Acts like a variable that contains the semantic value for the
 grouping made by the current rule.  @xref{Actions}.

+@end deffn

 
 

-@item $@var{n}
+@deffn {Variable} $@var{n}

 Acts like a variable that contains the semantic value for the
 @var{n}th component of the current rule.  @xref{Actions}.
 Acts like a variable that contains the semantic value for the
 @var{n}th component of the current rule.  @xref{Actions}.

+@end deffn

 
 

-@item $<@var{typealt}>$
+@deffn {Variable} $<@var{typealt}>$

 Like @code{$$} but specifies alternative @var{typealt} in the union
 specified by the @code{%union} declaration.  @xref{Action Types, ,Data
 Types of Values in Actions}.
 Like @code{$$} but specifies alternative @var{typealt} in the union
 specified by the @code{%union} declaration.  @xref{Action Types, ,Data
 Types of Values in Actions}.

+@end deffn

 
 

-@item $<@var{typealt}>@var{n}
+@deffn {Variable} $<@var{typealt}>@var{n}

 Like @code{$@var{n}} but specifies alternative @var{typealt} in the
 union specified by the @code{%union} declaration.
 @xref{Action Types, ,Data Types of Values in Actions}.
 Like @code{$@var{n}} but specifies alternative @var{typealt} in the
 union specified by the @code{%union} declaration.
 @xref{Action Types, ,Data Types of Values in Actions}.

+@end deffn

 
 

-@item YYABORT;
+@deffn {Macro} YYABORT;

 Return immediately from @code{yyparse}, indicating failure.
 @xref{Parser Function, ,The Parser Function @code{yyparse}}.
 Return immediately from @code{yyparse}, indicating failure.
 @xref{Parser Function, ,The Parser Function @code{yyparse}}.

+@end deffn

 
 

-@item YYACCEPT;
+@deffn {Macro} YYACCEPT;

 Return immediately from @code{yyparse}, indicating success.
 @xref{Parser Function, ,The Parser Function @code{yyparse}}.
 Return immediately from @code{yyparse}, indicating success.
 @xref{Parser Function, ,The Parser Function @code{yyparse}}.

+@end deffn

 
 

-@item YYBACKUP (@var{token}, @var{value});
+@deffn {Macro} YYBACKUP (@var{token}, @var{value});

 @findex YYBACKUP
 Unshift a token.  This macro is allowed only for rules that reduce
 a single value, and only when there is no look-ahead token.
 @findex YYBACKUP
 Unshift a token.  This macro is allowed only for rules that reduce
 a single value, and only when there is no look-ahead token.


@@ -4172,40 +4291,47 @@ a message @samp{cannot back up} and performs ordinary error
 recovery.
 
 In either case, the rest of the action is not executed.
 recovery.
 
 In either case, the rest of the action is not executed.

+@end deffn

 
 

-@item YYEMPTY
+@deffn {Macro} YYEMPTY

 @vindex YYEMPTY
 Value stored in @code{yychar} when there is no look-ahead token.
 @vindex YYEMPTY
 Value stored in @code{yychar} when there is no look-ahead token.

+@end deffn

 
 

-@item YYERROR;
+@deffn {Macro} YYERROR;

 @findex YYERROR
 Cause an immediate syntax error.  This statement initiates error
 recovery just as if the parser itself had detected an error; however, it
 does not call @code{yyerror}, and does not print any message.  If you
 want to print an error message, call @code{yyerror} explicitly before
 the @samp{YYERROR;} statement.  @xref{Error Recovery}.
 @findex YYERROR
 Cause an immediate syntax error.  This statement initiates error
 recovery just as if the parser itself had detected an error; however, it
 does not call @code{yyerror}, and does not print any message.  If you
 want to print an error message, call @code{yyerror} explicitly before
 the @samp{YYERROR;} statement.  @xref{Error Recovery}.

+@end deffn

 
 

-@item YYRECOVERING
+@deffn {Macro} YYRECOVERING

 This macro stands for an expression that has the value 1 when the parser
 is recovering from a syntax error, and 0 the rest of the time.
 @xref{Error Recovery}.
 This macro stands for an expression that has the value 1 when the parser
 is recovering from a syntax error, and 0 the rest of the time.
 @xref{Error Recovery}.

+@end deffn

 
 

-@item yychar
+@deffn {Variable} yychar

 Variable containing the current look-ahead token.  (In a pure parser,
 this is actually a local variable within @code{yyparse}.)  When there is
 no look-ahead token, the value @code{YYEMPTY} is stored in the variable.
 @xref{Look-Ahead, ,Look-Ahead Tokens}.
 Variable containing the current look-ahead token.  (In a pure parser,
 this is actually a local variable within @code{yyparse}.)  When there is
 no look-ahead token, the value @code{YYEMPTY} is stored in the variable.
 @xref{Look-Ahead, ,Look-Ahead Tokens}.

+@end deffn

 
 

-@item yyclearin;
+@deffn {Macro} yyclearin;

 Discard the current look-ahead token.  This is useful primarily in
 error rules.  @xref{Error Recovery}.
 Discard the current look-ahead token.  This is useful primarily in
 error rules.  @xref{Error Recovery}.

+@end deffn

 
 

-@item yyerrok;
+@deffn {Macro} yyerrok;

 Resume generating error messages immediately for subsequent syntax
 errors.  This is useful primarily in error rules.
 @xref{Error Recovery}.
 Resume generating error messages immediately for subsequent syntax
 errors.  This is useful primarily in error rules.
 @xref{Error Recovery}.

+@end deffn

 
 

-@item @@$
+@deffn {Value} @@$

 @findex @@$
 Acts like a structure variable containing information on the textual position
 of the grouping made by the current rule.  @xref{Locations, ,
 @findex @@$
 Acts like a structure variable containing information on the textual position
 of the grouping made by the current rule.  @xref{Locations, ,


@@ -4229,14 +4355,15 @@ Tracking Locations}.
 @c those members.
 
 @c The use of this feature makes the parser noticeably slower.
 @c those members.
 
 @c The use of this feature makes the parser noticeably slower.

+@end deffn

 
 

-@item @@@var{n}
+@deffn {Value} @@@var{n}

 @findex @@@var{n}
 Acts like a structure variable containing information on the textual position
 of the @var{n}th component of the current rule.  @xref{Locations, ,
 Tracking Locations}.
 @findex @@@var{n}
 Acts like a structure variable containing information on the textual position
 of the @var{n}th component of the current rule.  @xref{Locations, ,
 Tracking Locations}.

+@end deffn

 
 

-@end table

 
 @node Algorithm
 @chapter The Bison Parser Algorithm
 
 @node Algorithm
 @chapter The Bison Parser Algorithm


@@ -5029,7 +5156,7 @@ provided which addresses this issue.
 @cindex error recovery
 @cindex recovery from errors
 
 @cindex error recovery
 @cindex recovery from errors
 

-It is not usually acceptable to have a program terminate on a parse
+It is not usually acceptable to have a program terminate on a syntax

 error.  For example, a compiler should recover sufficiently to parse the
 rest of the input file and check it for errors; a calculator should accept
 another expression.
 error.  For example, a compiler should recover sufficiently to parse the
 rest of the input file and check it for errors; a calculator should accept
 another expression.


@@ -5071,15 +5198,17 @@ will be tokens to read before the next newline.  So the rule is not
 applicable in the ordinary way.
 
 But Bison can force the situation to fit the rule, by discarding part of
 applicable in the ordinary way.
 
 But Bison can force the situation to fit the rule, by discarding part of

-the semantic context and part of the input.  First it discards states and
-objects from the stack until it gets back to a state in which the
+the semantic context and part of the input.  First it discards states
+and objects from the stack until it gets back to a state in which the

 @code{error} token is acceptable.  (This means that the subexpressions
 @code{error} token is acceptable.  (This means that the subexpressions

-already parsed are discarded, back to the last complete @code{stmnts}.)  At
-this point the @code{error} token can be shifted.  Then, if the old
+already parsed are discarded, back to the last complete @code{stmnts}.)
+At this point the @code{error} token can be shifted.  Then, if the old

 look-ahead token is not acceptable to be shifted next, the parser reads
 tokens and discards them until it finds a token which is acceptable.  In
 look-ahead token is not acceptable to be shifted next, the parser reads
 tokens and discards them until it finds a token which is acceptable.  In

-this example, Bison reads and discards input until the next newline
-so that the fourth rule can apply.
+this example, Bison reads and discards input until the next newline so
+that the fourth rule can apply.  Note that discarded symbols are
+possible sources of memory leaks, see @ref{Destructor Decl, , Freeing
+Discarded Symbols}, for a means to reclaim this memory.

 
 The choice of error rules in the grammar is a choice of strategies for
 error recovery.  A simple and useful strategy is simply to skip the rest of
 
 The choice of error rules in the grammar is a choice of strategies for
 error recovery.  A simple and useful strategy is simply to skip the rest of


@@ -5130,7 +5259,7 @@ this is unacceptable, then the macro @code{yyclearin} may be used to clear
 this token.  Write the statement @samp{yyclearin;} in the error rule's
 action.
 
 this token.  Write the statement @samp{yyclearin;} in the error rule's
 action.
 

-For example, suppose that on a parse error, an error handling routine is
+For example, suppose that on a syntax error, an error handling routine is

 called that advances the input stream to some point where parsing should
 once again commence.  The next symbol returned by the lexical scanner is
 probably correct.  The previous look-ahead token ought to be discarded
 called that advances the input stream to some point where parsing should
 once again commence.  The next symbol returned by the lexical scanner is
 probably correct.  The previous look-ahead token ought to be discarded


@@ -5517,7 +5646,7 @@ after having reduced a rule that produced an @code{exp}, the control
 flow jumps to state 2.  If there is no such transition on a nonterminal
 symbol, and the lookahead is a @code{NUM}, then this token is shifted on
 the parse stack, and the control flow jumps to state 1.  Any other
 flow jumps to state 2.  If there is no such transition on a nonterminal
 symbol, and the lookahead is a @code{NUM}, then this token is shifted on
 the parse stack, and the control flow jumps to state 1.  Any other

-lookahead triggers a parse error.''
+lookahead triggers a syntax error.''

 
 @cindex core, item set
 @cindex item set core
 
 @cindex core, item set
 @cindex item set core


@@ -5585,7 +5714,7 @@ because of the item @samp{exp -> exp . '+' exp}, if the lookahead if
 @samp{+}, it will be shifted on the parse stack, and the automaton
 control will jump to state 4, corresponding to the item @samp{exp -> exp
 '+' . exp}.  Since there is no default action, any other token than
 @samp{+}, it will be shifted on the parse stack, and the automaton
 control will jump to state 4, corresponding to the item @samp{exp -> exp
 '+' . exp}.  Since there is no default action, any other token than

-those listed above will trigger a parse error.
+those listed above will trigger a syntax error.

 
 The state 3 is named the @dfn{final state}, or the @dfn{accepting
 state}:
 
 The state 3 is named the @dfn{final state}, or the @dfn{accepting
 state}:


@@ -5857,9 +5986,9 @@ static void
 yyprint (FILE *file, int type, YYSTYPE value)
 @{
   if (type == VAR)
 yyprint (FILE *file, int type, YYSTYPE value)
 @{
   if (type == VAR)

-    fprintf (file, " %s", value.tptr->name);
+    fprintf (file, "%s", value.tptr->name);

   else if (type == NUM)
   else if (type == NUM)

-    fprintf (file, " %d", value.val);
+    fprintf (file, "%d", value.val);

 @}
 @end smallexample
 
 @}
 @end smallexample
 


@@ -5907,7 +6036,6 @@ will produce @file{output.c++} and @file{outfile.h++}.
 * Bison Options::     All the options described in detail,
                         in alphabetical order by short options.
 * Option Cross Key::  Alphabetical list of long options.
 * Bison Options::     All the options described in detail,
                         in alphabetical order by short options.
 * Option Cross Key::  Alphabetical list of long options.

-* VMS Invocation::    Bison command syntax on @acronym{VMS}.

 @end menu
 
 @node Bison Options
 @end menu
 
 @node Bison Options


@@ -6099,34 +6227,6 @@ the corresponding short option.
 @end example
 @end ifinfo
 
 @end example
 @end ifinfo
 

-@node VMS Invocation
-@section Invoking Bison under @acronym{VMS}
-@cindex invoking Bison under @acronym{VMS}
-@cindex @acronym{VMS}
-
-The command line syntax for Bison on @acronym{VMS} is a variant of the usual
-Bison command syntax---adapted to fit @acronym{VMS} conventions.
-
-To find the @acronym{VMS} equivalent for any Bison option, start with the long
-option, and substitute a @samp{/} for the leading @samp{--}, and
-substitute a @samp{_} for each @samp{-} in the name of the long option.
-For example, the following invocation under @acronym{VMS}:
-
-@example
-bison /debug/name_prefix=bar foo.y
-@end example
-
-@noindent
-is equivalent to the following command under @acronym{POSIX}.
-
-@example
-bison --debug --name-prefix=bar foo.y
-@end example
-
-The @acronym{VMS} file system does not permit filenames such as
-@file{foo.tab.c}.  In the above example, the output file
-would instead be named @file{foo_tab.c}.
-

 @c ================================================= Invoking Bison
 
 @node FAQ
 @c ================================================= Invoking Bison
 
 @node FAQ


@@ -6159,303 +6259,358 @@ This question is already addressed elsewhere, @xref{Recursion,
 @cindex Bison symbols, table of
 @cindex symbols in Bison, table of
 
 @cindex Bison symbols, table of
 @cindex symbols in Bison, table of
 

-@table @code
-@item @@$
+@deffn {Variable} @@$

 In an action, the location of the left-hand side of the rule.
 @xref{Locations, , Locations Overview}.
 In an action, the location of the left-hand side of the rule.
 @xref{Locations, , Locations Overview}.

+@end deffn

 
 

-@item @@@var{n}
+@deffn {Variable} @@@var{n}

 In an action, the location of the @var{n}-th symbol of the right-hand
 side of the rule.  @xref{Locations, , Locations Overview}.
 In an action, the location of the @var{n}-th symbol of the right-hand
 side of the rule.  @xref{Locations, , Locations Overview}.

+@end deffn

 
 

-@item $$
+@deffn {Variable} $$

 In an action, the semantic value of the left-hand side of the rule.
 @xref{Actions}.
 In an action, the semantic value of the left-hand side of the rule.
 @xref{Actions}.

+@end deffn

 
 

-@item $@var{n}
+@deffn {Variable} $@var{n}

 In an action, the semantic value of the @var{n}-th symbol of the
 right-hand side of the rule.  @xref{Actions}.
 In an action, the semantic value of the @var{n}-th symbol of the
 right-hand side of the rule.  @xref{Actions}.

+@end deffn

 
 

-@item $accept
+@deffn {Symbol} $accept

 The predefined nonterminal whose only rule is @samp{$accept: @var{start}
 $end}, where @var{start} is the start symbol.  @xref{Start Decl, , The
 Start-Symbol}.  It cannot be used in the grammar.
 The predefined nonterminal whose only rule is @samp{$accept: @var{start}
 $end}, where @var{start} is the start symbol.  @xref{Start Decl, , The
 Start-Symbol}.  It cannot be used in the grammar.

+@end deffn

 
 

-@item $end
+@deffn {Symbol} $end

 The predefined token marking the end of the token stream.  It cannot be
 used in the grammar.
 The predefined token marking the end of the token stream.  It cannot be
 used in the grammar.

+@end deffn

 
 

-@item $undefined
+@deffn {Symbol} $undefined

 The predefined token onto which all undefined values returned by
 @code{yylex} are mapped.  It cannot be used in the grammar, rather, use
 @code{error}.
 The predefined token onto which all undefined values returned by
 @code{yylex} are mapped.  It cannot be used in the grammar, rather, use
 @code{error}.

+@end deffn

 
 

-@item error
+@deffn {Symbol} error

 A token name reserved for error recovery.  This token may be used in
 grammar rules so as to allow the Bison parser to recognize an error in
 the grammar without halting the process.  In effect, a sentence
 A token name reserved for error recovery.  This token may be used in
 grammar rules so as to allow the Bison parser to recognize an error in
 the grammar without halting the process.  In effect, a sentence

-containing an error may be recognized as valid.  On a parse error, the
+containing an error may be recognized as valid.  On a syntax error, the

 token @code{error} becomes the current look-ahead token.  Actions
 corresponding to @code{error} are then executed, and the look-ahead
 token is reset to the token that originally caused the violation.
 @xref{Error Recovery}.
 token @code{error} becomes the current look-ahead token.  Actions
 corresponding to @code{error} are then executed, and the look-ahead
 token is reset to the token that originally caused the violation.
 @xref{Error Recovery}.

+@end deffn

 
 

-@item YYABORT
+@deffn {Macro} YYABORT

 Macro to pretend that an unrecoverable syntax error has occurred, by
 making @code{yyparse} return 1 immediately.  The error reporting
 function @code{yyerror} is not called.  @xref{Parser Function, ,The
 Parser Function @code{yyparse}}.
 Macro to pretend that an unrecoverable syntax error has occurred, by
 making @code{yyparse} return 1 immediately.  The error reporting
 function @code{yyerror} is not called.  @xref{Parser Function, ,The
 Parser Function @code{yyparse}}.

+@end deffn

 
 

-@item YYACCEPT
+@deffn {Macro} YYACCEPT

 Macro to pretend that a complete utterance of the language has been
 read, by making @code{yyparse} return 0 immediately.
 @xref{Parser Function, ,The Parser Function @code{yyparse}}.
 Macro to pretend that a complete utterance of the language has been
 read, by making @code{yyparse} return 0 immediately.
 @xref{Parser Function, ,The Parser Function @code{yyparse}}.

+@end deffn

 
 

-@item YYBACKUP
+@deffn {Macro} YYBACKUP

 Macro to discard a value from the parser stack and fake a look-ahead
 token.  @xref{Action Features, ,Special Features for Use in Actions}.
 Macro to discard a value from the parser stack and fake a look-ahead
 token.  @xref{Action Features, ,Special Features for Use in Actions}.

+@end deffn

 
 

-@item YYDEBUG
+@deffn {Macro} YYDEBUG

 Macro to define to equip the parser with tracing code.  @xref{Tracing,
 ,Tracing Your Parser}.
 Macro to define to equip the parser with tracing code.  @xref{Tracing,
 ,Tracing Your Parser}.

+@end deffn

 
 

-@item YYERROR
+@deffn {Macro} YYERROR

 Macro to pretend that a syntax error has just been detected: call
 @code{yyerror} and then perform normal error recovery if possible
 (@pxref{Error Recovery}), or (if recovery is impossible) make
 @code{yyparse} return 1.  @xref{Error Recovery}.
 Macro to pretend that a syntax error has just been detected: call
 @code{yyerror} and then perform normal error recovery if possible
 (@pxref{Error Recovery}), or (if recovery is impossible) make
 @code{yyparse} return 1.  @xref{Error Recovery}.

+@end deffn

 
 

-@item YYERROR_VERBOSE
+@deffn {Macro} YYERROR_VERBOSE

 An obsolete macro that you define with @code{#define} in the Bison
 declarations section to request verbose, specific error message strings
 when @code{yyerror} is called.  It doesn't matter what definition you
 use for @code{YYERROR_VERBOSE}, just whether you define it.  Using
 @code{%error-verbose} is preferred.
 An obsolete macro that you define with @code{#define} in the Bison
 declarations section to request verbose, specific error message strings
 when @code{yyerror} is called.  It doesn't matter what definition you
 use for @code{YYERROR_VERBOSE}, just whether you define it.  Using
 @code{%error-verbose} is preferred.

+@end deffn

 
 

-@item YYINITDEPTH
+@deffn {Macro} YYINITDEPTH

 Macro for specifying the initial size of the parser stack.
 @xref{Stack Overflow}.
 Macro for specifying the initial size of the parser stack.
 @xref{Stack Overflow}.

+@end deffn

 
 

-@item YYLEX_PARAM
+@deffn {Macro} YYLEX_PARAM

 An obsolete macro for specifying an extra argument (or list of extra
 arguments) for @code{yyparse} to pass to @code{yylex}.  he use of this
 macro is deprecated, and is supported only for Yacc like parsers.
 @xref{Pure Calling,, Calling Conventions for Pure Parsers}.
 An obsolete macro for specifying an extra argument (or list of extra
 arguments) for @code{yyparse} to pass to @code{yylex}.  he use of this
 macro is deprecated, and is supported only for Yacc like parsers.
 @xref{Pure Calling,, Calling Conventions for Pure Parsers}.

+@end deffn

 
 

-@item YYLTYPE
+@deffn {Macro} YYLTYPE

 Macro for the data type of @code{yylloc}; a structure with four
 members.  @xref{Location Type, , Data Types of Locations}.
 Macro for the data type of @code{yylloc}; a structure with four
 members.  @xref{Location Type, , Data Types of Locations}.

+@end deffn

 
 

-@item yyltype
+@deffn {Type} yyltype

 Default value for YYLTYPE.
 Default value for YYLTYPE.

+@end deffn

 
 

-@item YYMAXDEPTH
-Macro for specifying the maximum size of the parser stack.
-@xref{Stack Overflow}.
+@deffn {Macro} YYMAXDEPTH
+Macro for specifying the maximum size of the parser stack.  @xref{Stack
+Overflow}.
+@end deffn

 
 

-@item YYPARSE_PARAM
+@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
 is supported only for Yacc like parsers.  @xref{Pure Calling,, Calling
 Conventions for Pure Parsers}.
 An obsolete macro for specifying the name of a parameter that
 @code{yyparse} should accept.  The use of this macro is deprecated, and
 is supported only for Yacc like parsers.  @xref{Pure Calling,, Calling
 Conventions for Pure Parsers}.

+@end deffn

 
 

-@item YYRECOVERING
+@deffn {Macro} YYRECOVERING

 Macro whose value indicates whether the parser is recovering from a
 syntax error.  @xref{Action Features, ,Special Features for Use in Actions}.
 Macro whose value indicates whether the parser is recovering from a
 syntax error.  @xref{Action Features, ,Special Features for Use in Actions}.

+@end deffn

 
 

-@item YYSTACK_USE_ALLOCA
+@deffn {Macro} YYSTACK_USE_ALLOCA

 Macro used to control the use of @code{alloca}.  If defined to @samp{0},
 the parser will not use @code{alloca} but @code{malloc} when trying to
 grow its internal stacks.  Do @emph{not} define @code{YYSTACK_USE_ALLOCA}
 to anything else.
 Macro used to control the use of @code{alloca}.  If defined to @samp{0},
 the parser will not use @code{alloca} but @code{malloc} when trying to
 grow its internal stacks.  Do @emph{not} define @code{YYSTACK_USE_ALLOCA}
 to anything else.

+@end deffn

 
 

-@item YYSTYPE
+@deffn {Macro} YYSTYPE

 Macro for the data type of semantic values; @code{int} by default.
 @xref{Value Type, ,Data Types of Semantic Values}.
 Macro for the data type of semantic values; @code{int} by default.
 @xref{Value Type, ,Data Types of Semantic Values}.

+@end deffn

 
 

-@item yychar
+@deffn {Variable} yychar

 External integer variable that contains the integer value of the current
 look-ahead token.  (In a pure parser, it is a local variable within
 @code{yyparse}.)  Error-recovery rule actions may examine this variable.
 @xref{Action Features, ,Special Features for Use in Actions}.
 External integer variable that contains the integer value of the current
 look-ahead token.  (In a pure parser, it is a local variable within
 @code{yyparse}.)  Error-recovery rule actions may examine this variable.
 @xref{Action Features, ,Special Features for Use in Actions}.

+@end deffn

 
 

-@item yyclearin
+@deffn {Variable} yyclearin

 Macro used in error-recovery rule actions.  It clears the previous
 look-ahead token.  @xref{Error Recovery}.
 Macro used in error-recovery rule actions.  It clears the previous
 look-ahead token.  @xref{Error Recovery}.

+@end deffn

 
 

-@item yydebug
+@deffn {Variable} yydebug

 External integer variable set to zero by default.  If @code{yydebug}
 is given a nonzero value, the parser will output information on input
 symbols and parser action.  @xref{Tracing, ,Tracing Your Parser}.
 External integer variable set to zero by default.  If @code{yydebug}
 is given a nonzero value, the parser will output information on input
 symbols and parser action.  @xref{Tracing, ,Tracing Your Parser}.

+@end deffn

 
 

-@item yyerrok
+@deffn {Macro} yyerrok

 Macro to cause parser to recover immediately to its normal mode
 Macro to cause parser to recover immediately to its normal mode

-after a parse error.  @xref{Error Recovery}.
+after a syntax error.  @xref{Error Recovery}.
+@end deffn

 
 

-@item yyerror
+@deffn {Function} yyerror

 User-supplied function to be called by @code{yyparse} on error.  The
 function receives one argument, a pointer to a character string
 containing an error message.  @xref{Error Reporting, ,The Error
 Reporting Function @code{yyerror}}.
 User-supplied function to be called by @code{yyparse} on error.  The
 function receives one argument, a pointer to a character string
 containing an error message.  @xref{Error Reporting, ,The Error
 Reporting Function @code{yyerror}}.

+@end deffn

 
 

-@item yylex
+@deffn {Function} yylex

 User-supplied lexical analyzer function, called with no arguments to get
 the next token.  @xref{Lexical, ,The Lexical Analyzer Function
 @code{yylex}}.
 User-supplied lexical analyzer function, called with no arguments to get
 the next token.  @xref{Lexical, ,The Lexical Analyzer Function
 @code{yylex}}.

+@end deffn

 
 

-@item yylval
+@deffn {Variable} yylval

 External variable in which @code{yylex} should place the semantic
 value associated with a token.  (In a pure parser, it is a local
 variable within @code{yyparse}, and its address is passed to
 @code{yylex}.)  @xref{Token Values, ,Semantic Values of Tokens}.
 External variable in which @code{yylex} should place the semantic
 value associated with a token.  (In a pure parser, it is a local
 variable within @code{yyparse}, and its address is passed to
 @code{yylex}.)  @xref{Token Values, ,Semantic Values of Tokens}.

+@end deffn

 
 

-@item yylloc
+@deffn {Variable} yylloc

 External variable in which @code{yylex} should place the line and column
 numbers associated with a token.  (In a pure parser, it is a local
 variable within @code{yyparse}, and its address is passed to
 @code{yylex}.)  You can ignore this variable if you don't use the
 @samp{@@} feature in the grammar actions.  @xref{Token Positions,
 ,Textual Positions of Tokens}.
 External variable in which @code{yylex} should place the line and column
 numbers associated with a token.  (In a pure parser, it is a local
 variable within @code{yyparse}, and its address is passed to
 @code{yylex}.)  You can ignore this variable if you don't use the
 @samp{@@} feature in the grammar actions.  @xref{Token Positions,
 ,Textual Positions of Tokens}.

+@end deffn

 
 

-@item yynerrs
-Global variable which Bison increments each time there is a parse error.
+@deffn {Variable} yynerrs
+Global variable which Bison increments each time there is a syntax error.

 (In a pure parser, it is a local variable within @code{yyparse}.)
 @xref{Error Reporting, ,The Error Reporting Function @code{yyerror}}.
 (In a pure parser, it is a local variable within @code{yyparse}.)
 @xref{Error Reporting, ,The Error Reporting Function @code{yyerror}}.

+@end deffn

 
 

-@item yyparse
+@deffn {Function} yyparse

 The parser function produced by Bison; call this function to start
 parsing.  @xref{Parser Function, ,The Parser Function @code{yyparse}}.
 The parser function produced by Bison; call this function to start
 parsing.  @xref{Parser Function, ,The Parser Function @code{yyparse}}.

+@end deffn

 
 

-@item %debug
+@deffn {Directive} %debug

 Equip the parser for debugging.  @xref{Decl Summary}.
 Equip the parser for debugging.  @xref{Decl Summary}.

+@end deffn

 
 

-@item %defines
+@deffn {Directive} %defines

 Bison declaration to create a header file meant for the scanner.
 @xref{Decl Summary}.
 Bison declaration to create a header file meant for the scanner.
 @xref{Decl Summary}.

+@end deffn

 
 

-@item %dprec
+@deffn {Directive} %destructor
+Specifying how the parser should reclaim the memory associated to
+discarded symbols. @xref{Destructor Decl, , Freeing Discarded Symbols}.
+@end deffn
+
+@deffn {Directive} %dprec

 Bison declaration to assign a precedence to a rule that is used at parse
 time to resolve reduce/reduce conflicts.  @xref{GLR Parsers, ,Writing
 @acronym{GLR} Parsers}.
 Bison declaration to assign a precedence to a rule that is used at parse
 time to resolve reduce/reduce conflicts.  @xref{GLR Parsers, ,Writing
 @acronym{GLR} Parsers}.

+@end deffn

 
 

-@item %error-verbose
+@deffn {Directive} %error-verbose

 Bison declaration to request verbose, specific error message strings
 when @code{yyerror} is called.
 Bison declaration to request verbose, specific error message strings
 when @code{yyerror} is called.

+@end deffn

 
 

-@item %file-prefix="@var{prefix}"
+@deffn {Directive} %file-prefix="@var{prefix}"

 Bison declaration to set the prefix of the output files.  @xref{Decl
 Summary}.
 Bison declaration to set the prefix of the output files.  @xref{Decl
 Summary}.

+@end deffn

 
 

-@item %glr-parser
+@deffn {Directive} %glr-parser

 Bison declaration to produce a @acronym{GLR} parser.  @xref{GLR
 Parsers, ,Writing @acronym{GLR} Parsers}.
 Bison declaration to produce a @acronym{GLR} parser.  @xref{GLR
 Parsers, ,Writing @acronym{GLR} Parsers}.

+@end deffn

 
 

-@c @item %source-extension
-@c Bison declaration to specify the generated parser output file extension.
-@c @xref{Decl Summary}.
-@c
-@c @item %header-extension
-@c Bison declaration to specify the generated parser header file extension
-@c if required.  @xref{Decl Summary}.
-
-@item %left
+@deffn {Directive} %left

 Bison declaration to assign left associativity to token(s).
 @xref{Precedence Decl, ,Operator Precedence}.
 Bison declaration to assign left associativity to token(s).
 @xref{Precedence Decl, ,Operator Precedence}.

+@end deffn

 
 

-@item %lex-param "@var{argument-declaration}" "@var{argument-name}"
+@deffn {Directive} %lex-param @{@var{argument-declaration}@}. @{@var{argument-name}"@}

 Bison declaration to specifying an additional parameter that
 @code{yylex} should accept.  @xref{Pure Calling,, Calling Conventions
 for Pure Parsers}.
 Bison declaration to specifying an additional parameter that
 @code{yylex} should accept.  @xref{Pure Calling,, Calling Conventions
 for Pure Parsers}.

+@end deffn

 
 

-@item %merge
+@deffn {Directive} %merge

 Bison declaration to assign a merging function to a rule.  If there is a
 reduce/reduce conflict with a rule having the same merging function, the
 function is applied to the two semantic values to get a single result.
 @xref{GLR Parsers, ,Writing @acronym{GLR} Parsers}.
 Bison declaration to assign a merging function to a rule.  If there is a
 reduce/reduce conflict with a rule having the same merging function, the
 function is applied to the two semantic values to get a single result.
 @xref{GLR Parsers, ,Writing @acronym{GLR} Parsers}.

+@end deffn

 
 

-@item %name-prefix="@var{prefix}"
+@deffn {Directive} %name-prefix="@var{prefix}"

 Bison declaration to rename the external symbols.  @xref{Decl Summary}.
 Bison declaration to rename the external symbols.  @xref{Decl Summary}.

+@end deffn

 
 

-@item %no-lines
+@deffn {Directive} %no-lines

 Bison declaration to avoid generating @code{#line} directives in the
 parser file.  @xref{Decl Summary}.
 Bison declaration to avoid generating @code{#line} directives in the
 parser file.  @xref{Decl Summary}.

+@end deffn

 
 

-@item %nonassoc
+@deffn {Directive} %nonassoc

 Bison declaration to assign non-associativity to token(s).
 @xref{Precedence Decl, ,Operator Precedence}.
 Bison declaration to assign non-associativity to token(s).
 @xref{Precedence Decl, ,Operator Precedence}.

+@end deffn

 
 

-@item %output="@var{filename}"
+@deffn {Directive} %output="@var{filename}"

 Bison declaration to set the name of the parser file.  @xref{Decl
 Summary}.
 Bison declaration to set the name of the parser file.  @xref{Decl
 Summary}.

+@end deffn

 
 

-@item %parse-param "@var{argument-declaration}" "@var{argument-name}"
+@deffn {Directive} %parse-param @{@var{argument-declaration}@}, @{@var{argument-name}@}

 Bison declaration to specifying an additional parameter that
 @code{yyparse} should accept.  @xref{Parser Function,, The Parser
 Function @code{yyparse}}.
 Bison declaration to specifying an additional parameter that
 @code{yyparse} should accept.  @xref{Parser Function,, The Parser
 Function @code{yyparse}}.

+@end deffn

 
 

-@item %prec
+@deffn {Directive} %prec

 Bison declaration to assign a precedence to a specific rule.
 @xref{Contextual Precedence, ,Context-Dependent Precedence}.
 Bison declaration to assign a precedence to a specific rule.
 @xref{Contextual Precedence, ,Context-Dependent Precedence}.

+@end deffn

 
 

-@item %pure-parser
+@deffn {Directive} %pure-parser

 Bison declaration to request a pure (reentrant) parser.
 @xref{Pure Decl, ,A Pure (Reentrant) Parser}.
 Bison declaration to request a pure (reentrant) parser.
 @xref{Pure Decl, ,A Pure (Reentrant) Parser}.

+@end deffn

 
 

-@item %right
+@deffn {Directive} %right

 Bison declaration to assign right associativity to token(s).
 @xref{Precedence Decl, ,Operator Precedence}.
 Bison declaration to assign right associativity to token(s).
 @xref{Precedence Decl, ,Operator Precedence}.

+@end deffn

 
 

-@item %start
+@deffn {Directive} %start

 Bison declaration to specify the start symbol.  @xref{Start Decl, ,The
 Start-Symbol}.
 Bison declaration to specify the start symbol.  @xref{Start Decl, ,The
 Start-Symbol}.

+@end deffn

 
 

-@item %token
+@deffn {Directive} %token

 Bison declaration to declare token(s) without specifying precedence.
 @xref{Token Decl, ,Token Type Names}.
 Bison declaration to declare token(s) without specifying precedence.
 @xref{Token Decl, ,Token Type Names}.

+@end deffn

 
 

-@item %token-table
+@deffn {Directive} %token-table

 Bison declaration to include a token name table in the parser file.
 @xref{Decl Summary}.
 Bison declaration to include a token name table in the parser file.
 @xref{Decl Summary}.

+@end deffn

 
 

-@item %type
+@deffn {Directive} %type

 Bison declaration to declare nonterminals.  @xref{Type Decl,
 ,Nonterminal Symbols}.
 Bison declaration to declare nonterminals.  @xref{Type Decl,
 ,Nonterminal Symbols}.

+@end deffn

 
 

-@item %union
+@deffn {Directive} %union

 Bison declaration to specify several possible data types for semantic
 values.  @xref{Union Decl, ,The Collection of Value Types}.
 Bison declaration to specify several possible data types for semantic
 values.  @xref{Union Decl, ,The Collection of Value Types}.

-@end table
+@end deffn

 
 @sp 1
 
 These are the punctuation and delimiters used in Bison input:
 
 
 @sp 1
 
 These are the punctuation and delimiters used in Bison input:
 

-@table @samp
-@item %%
+@deffn {Delimiter} %%

 Delimiter used to separate the grammar rule section from the
 Bison declarations section or the epilogue.
 @xref{Grammar Layout, ,The Overall Layout of a Bison Grammar}.
 Delimiter used to separate the grammar rule section from the
 Bison declarations section or the epilogue.
 @xref{Grammar Layout, ,The Overall Layout of a Bison Grammar}.

+@end deffn

 
 

-@item %@{ %@}
+@c Don't insert spaces, or check the DVI output.
+@deffn {Delimiter} %@{@var{code}%@}

 All code listed between @samp{%@{} and @samp{%@}} is copied directly to
 the output file uninterpreted.  Such code forms the prologue of the input
 file.  @xref{Grammar Outline, ,Outline of a Bison
 Grammar}.
 All code listed between @samp{%@{} and @samp{%@}} is copied directly to
 the output file uninterpreted.  Such code forms the prologue of the input
 file.  @xref{Grammar Outline, ,Outline of a Bison
 Grammar}.

+@end deffn

 
 

-@item /*@dots{}*/
+@deffn {Construct} /*@dots{}*/

 Comment delimiters, as in C.
 Comment delimiters, as in C.

+@end deffn

 
 

-@item :
+@deffn {Delimiter} :

 Separates a rule's result from its components.  @xref{Rules, ,Syntax of
 Grammar Rules}.
 Separates a rule's result from its components.  @xref{Rules, ,Syntax of
 Grammar Rules}.

+@end deffn

 
 

-@item ;
+@deffn {Delimiter} ;

 Terminates a rule.  @xref{Rules, ,Syntax of Grammar Rules}.
 Terminates a rule.  @xref{Rules, ,Syntax of Grammar Rules}.

+@end deffn

 
 

-@item |
+@deffn {Delimiter} |

 Separates alternate rules for the same result nonterminal.
 @xref{Rules, ,Syntax of Grammar Rules}.
 Separates alternate rules for the same result nonterminal.
 @xref{Rules, ,Syntax of Grammar Rules}.

-@end table
+@end deffn

 
 @node Glossary
 @appendix Glossary
 
 @node Glossary
 @appendix Glossary


@@ -6560,10 +6715,6 @@ A grammar symbol standing for a grammatical construct that can
 be expressed through rules in terms of smaller constructs; in other
 words, a construct that is not a token.  @xref{Symbols}.
 
 be expressed through rules in terms of smaller constructs; in other
 words, a construct that is not a token.  @xref{Symbols}.
 

-@item Parse error
-An error encountered during parsing of an input stream due to invalid
-syntax.  @xref{Error Recovery}.
-

 @item Parser
 A function that recognizes valid sentences of a language by analyzing
 the syntax structure of a set of tokens passed to it from a lexical
 @item Parser
 A function that recognizes valid sentences of a language by analyzing
 the syntax structure of a set of tokens passed to it from a lexical


@@ -6616,6 +6767,10 @@ A data structure where symbol names and associated data are stored
 during parsing to allow for recognition and use of existing
 information in repeated uses of a symbol.  @xref{Multi-function Calc}.
 
 during parsing to allow for recognition and use of existing
 information in repeated uses of a symbol.  @xref{Multi-function Calc}.
 

+@item Syntax error
+An error encountered during parsing of an input stream due to invalid
+syntax.  @xref{Error Recovery}.
+

 @item Token
 A basic, grammatically indivisible unit of a language.  The symbol
 that describes a token in the grammar is a terminal symbol.
 @item Token
 A basic, grammatically indivisible unit of a language.  The symbol
 that describes a token in the grammar is a terminal symbol.