Do not let the scan-skel token buffer grow unboundedly in the usual case.

[bison.git] / doc / bison.texinfo

diff --git a/doc/bison.texinfo b/doc/bison.texinfo
index 670a65ba56d0834785e53438c6ec1a2889d10ce6..8cabdb63e2452014cff3ae5deaa30800a7c1749e 100644 (file)
--- a/doc/bison.texinfo
+++ b/doc/bison.texinfo
@@ -3102,13 +3102,13 @@ When @code{YYLTYPE} is not defined, Bison uses a default structure type with
 four members:
 
 @example
 four members:
 
 @example

-struct
+typedef struct YYLTYPE

 @{
   int first_line;
   int first_column;
   int last_line;
   int last_column;
 @{
   int first_line;
   int first_column;
   int last_line;
   int last_column;

-@}
+@} YYLTYPE;

 @end example
 
 @node Actions and Locations
 @end example
 
 @node Actions and Locations


@@ -3186,17 +3186,23 @@ Actually, actions are not the best place to compute locations.  Since
 locations are much more general than semantic values, there is room in
 the output parser to redefine the default action to take for each
 rule.  The @code{YYLLOC_DEFAULT} macro is invoked each time a rule is
 locations are much more general than semantic values, there is room in
 the output parser to redefine the default action to take for each
 rule.  The @code{YYLLOC_DEFAULT} macro is invoked each time a rule is

-matched, before the associated action is run.
+matched, before the associated action is run.  It is also invoked
+while processing a syntax error, to compute the error's location.

 
 Most of the time, this macro is general enough to suppress location
 dedicated code from semantic actions.
 
 The @code{YYLLOC_DEFAULT} macro takes three parameters.  The first one is
 
 Most of the time, this macro is general enough to suppress location
 dedicated code from semantic actions.
 
 The @code{YYLLOC_DEFAULT} macro takes three parameters.  The first one is

-the location of the grouping (the result of the computation).  The second one
-is an array holding locations of all right hand side elements of the rule
-being matched.  The last one is the size of the right hand side rule.
+the location of the grouping (the result of the computation).  When a
+rule is matched, the second parameter is an array holding locations of
+all right hand side elements of the rule being matched, and the third
+parameter is the size of the rule's right hand side.  When processing
+a syntax error, the second parameter is an array holding locations of
+the symbols that were discarded during error processing, and the third
+parameter is the number of discarded symbols.

 
 

-By default, it is defined this way for simple @acronym{LALR}(1) parsers:
+By default, @code{YYLLOC_DEFAULT} is defined this way for simple
+@acronym{LALR}(1) parsers:

 
 @example
 @group
 
 @example
 @group


@@ -3417,7 +3423,23 @@ This says that the two alternative types are @code{double} and @code{symrec
 in the @code{%token} and @code{%type} declarations to pick one of the types
 for a terminal or nonterminal symbol (@pxref{Type Decl, ,Nonterminal Symbols}).
 
 in the @code{%token} and @code{%type} declarations to pick one of the types
 for a terminal or nonterminal symbol (@pxref{Type Decl, ,Nonterminal Symbols}).
 

-Note that, unlike making a @code{union} declaration in C, you do not write
+As an extension to @acronym{POSIX}, a tag is allowed after the
+@code{union}.  For example:
+
+@example
+@group
+%union value @{
+  double val;
+  symrec *tptr;
+@}
+@end group
+@end example
+
+specifies the union tag @code{value}, so the corresponding C type is
+@code{union value}.  If you do not specify a tag, it defaults to
+@code{YYSTYPE}.
+
+Note that, unlike making a @code{union} declaration in C, you need not write

 a semicolon after the closing brace.
 
 @node Type Decl
 a semicolon after the closing brace.
 
 @node Type Decl


@@ -3475,7 +3497,7 @@ should use @code{$$} to designate the semantic value associated to the
 (@pxref{Parser Function, , The Parser Function @code{yyparse}}).
 
 @strong{Warning:} as of Bison 1.875, this feature is still considered as
 (@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,
+experimental, as there was not enough user feedback.  In particular,

 the syntax might still change.
 @end deffn
 
 the syntax might still change.
 @end deffn
 


@@ -3753,7 +3775,8 @@ Request a pure (reentrant) parser program (@pxref{Pure Decl, ,A Pure
 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

-three elements of @code{yytname} are always @code{"$end"},
+three elements of @code{yytname} correspond to the predefined tokens
+@code{"$end"},

 @code{"error"}, and @code{"$undefined"}; after these come the symbols
 defined in the grammar file.
 
 @code{"error"}, and @code{"$undefined"}; after these come the symbols
 defined in the grammar file.
 


@@ -3879,6 +3902,12 @@ Return immediately with value 0 (to report success).
 Return immediately with value 1 (to report failure).
 @end defmac
 
 Return immediately with value 1 (to report failure).
 @end defmac
 

+@c For now, do not document %lex-param and %parse-param, since it's
+@c not clear that the current behavior is stable enough.  For example,
+@c we may need to add %error-param.
+@clear documentparam
+
+@ifset documentparam

 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}:
 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}:


@@ -3886,8 +3915,8 @@ declaration @code{%parse-param}:
 @deffn {Directive} %parse-param @{@var{argument-declaration}@}
 @findex %parse-param
 Declare that an argument declared by @code{argument-declaration} is an
 @deffn {Directive} %parse-param @{@var{argument-declaration}@}
 @findex %parse-param
 Declare that an argument declared by @code{argument-declaration} is an

-additional @code{yyparse} argument.  This argument is also passed to
-@code{yyerror}.  The @var{argument-declaration} is used when declaring
+additional @code{yyparse} argument.
+The @var{argument-declaration} is used when declaring

 functions or prototypes.  The last identifier in
 @var{argument-declaration} must be the argument name.
 @end deffn
 functions or prototypes.  The last identifier in
 @var{argument-declaration} must be the argument name.
 @end deffn


@@ -3917,6 +3946,7 @@ In the grammar actions, use expressions like this to refer to the data:
 @example
 exp: @dots{}    @{ @dots{}; *randomness += 1; @dots{} @}
 @end example
 @example
 exp: @dots{}    @{ @dots{}; *randomness += 1; @dots{} @}
 @end example

+@end ifset

 
 
 @node Lexical
 
 
 @node Lexical


@@ -4123,6 +4153,7 @@ this case, omit the second argument; @code{yylex} will be called with
 only one argument.
 
 
 only one argument.
 
 

+@ifset documentparam

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


@@ -4163,6 +4194,7 @@ and finally, if both @code{%pure-parser} and @code{%locations} are used:
 int yylex   (YYSTYPE *lvalp, YYLTYPE *llocp, int *nastiness);
 int yyparse (int *nastiness, int *randomness);
 @end example
 int yylex   (YYSTYPE *lvalp, YYLTYPE *llocp, int *nastiness);
 int yyparse (int *nastiness, int *randomness);
 @end example

+@end ifset

 
 @node Error Reporting
 @section The Error Reporting Function @code{yyerror}
 
 @node Error Reporting
 @section The Error Reporting Function @code{yyerror}


@@ -4227,11 +4259,12 @@ void yyerror (char const *msg);                 /* Yacc parsers.  */
 void yyerror (YYLTYPE *locp, char const *msg);  /* GLR parsers.   */
 @end example
 
 void yyerror (YYLTYPE *locp, char const *msg);  /* GLR parsers.   */
 @end example
 

+@ifset documentparam

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

-void yyerror (int *randomness, char const *msg);  /* Yacc parsers.  */
-void yyerror (int *randomness, char const *msg);  /* GLR parsers.   */
+void yyerror (int *nastiness, char const *msg);  /* Yacc parsers.  */
+void yyerror (int *nastiness, char const *msg);  /* GLR parsers.   */

 @end example
 
 Finally, GLR and Yacc parsers share the same @code{yyerror} calling
 @end example
 
 Finally, GLR and Yacc parsers share the same @code{yyerror} calling


@@ -4260,6 +4293,7 @@ void yyerror (YYLTYPE *locp,
               int *nastiness, int *randomness,
               char const *msg);
 @end example
               int *nastiness, int *randomness,
               char const *msg);
 @end example

+@end ifset

 
 @noindent
 The prototypes are only indications of how the code produced by Bison
 
 @noindent
 The prototypes are only indications of how the code produced by Bison


@@ -5575,8 +5609,8 @@ useless: STR;
 @example
 calc.y: warning: 1 useless nonterminal and 1 useless rule
 calc.y:11.1-7: warning: useless nonterminal: useless
 @example
 calc.y: warning: 1 useless nonterminal and 1 useless rule
 calc.y:11.1-7: warning: useless nonterminal: useless

-calc.y:11.8-12: warning: useless rule: useless: STR
-calc.y contains 7 shift/reduce conflicts.
+calc.y:11.10-12: warning: useless rule: useless: STR
+calc.y: conflicts: 7 shift/reduce

 @end example
 
 When given @option{--report=state}, in addition to @file{calc.tab.c}, it
 @end example
 
 When given @option{--report=state}, in addition to @file{calc.tab.c}, it


@@ -5598,10 +5632,10 @@ Conflict in state 8 between rule 2 and token '*' resolved as shift.
 The next section lists states that still have conflicts.
 
 @example
 The next section lists states that still have conflicts.
 
 @example

-State 8 contains 1 shift/reduce conflict.
-State 9 contains 1 shift/reduce conflict.
-State 10 contains 1 shift/reduce conflict.
-State 11 contains 4 shift/reduce conflicts.
+State 8 conflicts: 1 shift/reduce
+State 9 conflicts: 1 shift/reduce
+State 10 conflicts: 1 shift/reduce
+State 11 conflicts: 4 shift/reduce

 @end example
 
 @noindent
 @end example
 
 @noindent


@@ -5813,8 +5847,8 @@ state 7
     exp         go to state 11
 @end example
 
     exp         go to state 11
 @end example
 

-As was announced in beginning of the report, @samp{State 8 contains 1
-shift/reduce conflict}:
+As was announced in beginning of the report, @samp{State 8 conflicts:
+1 shift/reduce}:

 
 @example
 state 8
 
 @example
 state 8


@@ -6440,15 +6474,11 @@ macro is deprecated, and is supported only for Yacc like parsers.
 @xref{Pure Calling,, Calling Conventions for Pure Parsers}.
 @end deffn
 
 @xref{Pure Calling,, Calling Conventions for Pure Parsers}.
 @end deffn
 

-@deffn {Macro} YYLTYPE
-Macro for the data type of @code{yylloc}; a structure with four
+@deffn {Type} YYLTYPE
+Data type of @code{yylloc}; by default, a structure with four

 members.  @xref{Location Type, , Data Types of Locations}.
 @end deffn
 
 members.  @xref{Location Type, , Data Types of Locations}.
 @end deffn
 

-@deffn {Type} yyltype
-Default value for YYLTYPE.
-@end deffn
-

 @deffn {Macro} 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}.


@@ -6473,8 +6503,8 @@ grow its internal stacks.  Do @emph{not} define @code{YYSTACK_USE_ALLOCA}
 to anything else.
 @end deffn
 
 to anything else.
 @end deffn
 

-@deffn {Macro} YYSTYPE
-Macro for the data type of semantic values; @code{int} by default.
+@deffn {Type} YYSTYPE
+Data type of semantic values; @code{int} by default.

 @xref{Value Type, ,Data Types of Semantic Values}.
 @end deffn
 
 @xref{Value Type, ,Data Types of Semantic Values}.
 @end deffn
 


@@ -6580,11 +6610,13 @@ Bison declaration to assign left associativity to token(s).
 @xref{Precedence Decl, ,Operator Precedence}.
 @end deffn
 
 @xref{Precedence Decl, ,Operator Precedence}.
 @end deffn
 

+@ifset documentparam

 @deffn {Directive} %lex-param @{@var{argument-declaration}@}
 Bison declaration to specifying an additional parameter that
 @code{yylex} should accept.  @xref{Pure Calling,, Calling Conventions
 for Pure Parsers}.
 @end deffn
 @deffn {Directive} %lex-param @{@var{argument-declaration}@}
 Bison declaration to specifying an additional parameter that
 @code{yylex} should accept.  @xref{Pure Calling,, Calling Conventions
 for Pure Parsers}.
 @end deffn

+@end ifset

 
 @deffn {Directive} %merge
 Bison declaration to assign a merging function to a rule.  If there is a
 
 @deffn {Directive} %merge
 Bison declaration to assign a merging function to a rule.  If there is a


@@ -6612,11 +6644,13 @@ Bison declaration to set the name of the parser file.  @xref{Decl
 Summary}.
 @end deffn
 
 Summary}.
 @end deffn
 

+@ifset documentparam

 @deffn {Directive} %parse-param @{@var{argument-declaration}@}
 Bison declaration to specifying an additional parameter that
 @code{yyparse} should accept.  @xref{Parser Function,, The Parser
 Function @code{yyparse}}.
 @end deffn
 @deffn {Directive} %parse-param @{@var{argument-declaration}@}
 Bison declaration to specifying an additional parameter that
 @code{yyparse} should accept.  @xref{Parser Function,, The Parser
 Function @code{yyparse}}.
 @end deffn

+@end ifset

 
 @deffn {Directive} %prec
 Bison declaration to assign a precedence to a specific rule.
 
 @deffn {Directive} %prec
 Bison declaration to assign a precedence to a specific rule.