In an action, the location of the left-hand side of the rule. See Tracking Locations.
In an action, the location of the n-th symbol of the right-hand side of the rule. See Tracking Locations.
In a grammar, the Bison-generated nonterminal symbol for a mid-rule action with a semantical value. See Mid-Rule Action Translation.
In an action, the location of a symbol addressed by name. See Tracking Locations.
In a grammar, the Bison-generated nonterminal symbol for a mid-rule action with no semantical value. See Mid-Rule Action Translation.
In an action, the semantic value of the n-th symbol of the right-hand side of the rule. See Actions.
In an action, the semantic value of a symbol addressed by name. See Actions.
Delimiter used to separate the grammar rule section from the Bison declarations section or the epilogue. See The Overall Layout of a Bison Grammar.
All code listed between ‘%{’ and ‘%}’ is copied verbatim to the parser implementation file. Such code forms the prologue of the grammar file. See Outline of a Bison Grammar.
Separates alternate rules for the same result nonterminal. See Syntax of Grammar Rules.
Used to define a default tagged
%destructor
or default tagged%printer
.This feature is experimental. More user feedback will help to determine whether it should become a permanent feature.
Used to define a default tagless
%destructor
or default tagless%printer
.This feature is experimental. More user feedback will help to determine whether it should become a permanent feature.
The predefined nonterminal whose only rule is ‘$accept: start $end’, where start is the start symbol. See The Start-Symbol. It cannot be used in the grammar.
Insert code verbatim into the output parser source at the default location or at the location specified by qualifier. See %code Summary.
Define a variable to adjust Bison's behavior. See %define Summary.
Bison declaration to create a parser header file, which is usually meant for the scanner. See Decl Summary.
Same as above, but save in the file defines-file. See Decl Summary.
Specify how the parser should reclaim the memory associated to discarded symbols. See Freeing Discarded Symbols.
Bison declaration to assign a precedence to a rule that is used at parse time to resolve reduce/reduce conflicts. See Writing GLR Parsers.
The predefined token marking the end of the token stream. It cannot be used in the grammar.
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 syntax error, the token
error
becomes the current lookahead token. Actions corresponding toerror
are then executed, and the lookahead token is reset to the token that originally caused the violation. See Error Recovery.
Bison declaration to request verbose, specific error message strings when
yyerror
is called. See Error Reporting.
Bison declaration to set the prefix of the output files. See Decl Summary.
Bison declaration to assign left associativity to token(s). See Operator Precedence.
Bison declaration to specifying an additional parameter that
yylex
should accept. See Calling Conventions for Pure 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. See Writing GLR Parsers.
Obsoleted by the
%define
variableapi.prefix
(see Multiple Parsers in the Same Program).Rename the external symbols (variables and functions) used in the parser so that they start with prefix instead of ‘yy’. Contrary to
api.prefix
, do no rename types and macros.The precise list of symbols renamed in C parsers is
yyparse
,yylex
,yyerror
,yynerrs
,yylval
,yychar
,yydebug
, and (if locations are used)yylloc
. If you use a push parser,yypush_parse
,yypull_parse
,yypstate
,yypstate_new
andyypstate_delete
will also be renamed. For example, if you use ‘%name-prefix "c_"’, the names becomec_parse
,c_lex
, and so on. For C++ parsers, see the%define namespace
documentation in this section.
Bison declaration to avoid generating
#line
directives in the parser implementation file. See Decl Summary.
Bison declaration to assign nonassociativity to token(s). See Operator Precedence.
Bison declaration to set the name of the parser implementation file. See Decl Summary.
Bison declaration to specifying an additional parameter that
yyparse
should accept. See The Parser Functionyyparse
.
Bison declaration to assign a precedence to a specific rule. See Context-Dependent Precedence.
Deprecated version of
%define api.pure
(see api.pure), for which Bison is more careful to warn about unreasonable usage.
Require version version or higher of Bison. See Require a Version of Bison.
Bison declaration to assign right associativity to token(s). See Operator Precedence.
Bison declaration to declare token(s) without specifying precedence. See Token Type Names.
Bison declaration to include a token name table in the parser implementation file. See Decl Summary.
The predefined token onto which all undefined values returned by
yylex
are mapped. It cannot be used in the grammar, rather, useerror
.
Bison declaration to specify several possible data types for semantic values. See The Collection of Value Types.
Macro to pretend that an unrecoverable syntax error has occurred, by making
yyparse
return 1 immediately. The error reporting functionyyerror
is not called. See The Parser Functionyyparse
.For Java parsers, this functionality is invoked using
return YYABORT;
instead.
Macro to pretend that a complete utterance of the language has been read, by making
yyparse
return 0 immediately. See The Parser Functionyyparse
.For Java parsers, this functionality is invoked using
return YYACCEPT;
instead.
Macro to discard a value from the parser stack and fake a lookahead token. See Special Features for Use in Actions.
External integer variable that contains the integer value of the lookahead token. (In a pure parser, it is a local variable within
yyparse
.) Error-recovery rule actions may examine this variable. See Special Features for Use in Actions.
Macro used in error-recovery rule actions. It clears the previous lookahead token. See Error Recovery.
External integer variable set to zero by default. If
yydebug
is given a nonzero value, the parser will output information on input symbols and parser action. See Tracing Your Parser.
Macro to cause parser to recover immediately to its normal mode after a syntax error. See Error Recovery.
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
yyerror
, and does not print any message. If you want to print an error message, callyyerror
explicitly before the ‘YYERROR;’ statement. See Error Recovery.For Java parsers, this functionality is invoked using
return YYERROR;
instead.
User-supplied function to be called by
yyparse
on error. See The Error Reporting Functionyyerror
.
An obsolete macro that you define with
#define
in the prologue to request verbose, specific error message strings whenyyerror
is called. It doesn't matter what definition you use forYYERROR_VERBOSE
, just whether you define it. Supported by the C skeletons only; using%error-verbose
is preferred. See Error Reporting.
Macro for specifying the initial size of the parser stack. See Memory Management.
User-supplied lexical analyzer function, called with no arguments to get the next token. See The Lexical Analyzer Function
yylex
.
An obsolete macro for specifying an extra argument (or list of extra arguments) for
yyparse
to pass toyylex
. The use of this macro is deprecated, and is supported only for Yacc like parsers. See Calling Conventions for Pure Parsers.
External variable in which
yylex
should place the line and column numbers associated with a token. (In a pure parser, it is a local variable withinyyparse
, and its address is passed toyylex
.) You can ignore this variable if you don't use the ‘@’ feature in the grammar actions. See Textual Locations of Tokens. In semantic actions, it stores the location of the lookahead token. See Actions and Locations.
Data type of
yylloc
; by default, a structure with four members. See Data Types of Locations.
External variable in which
yylex
should place the semantic value associated with a token. (In a pure parser, it is a local variable withinyyparse
, and its address is passed toyylex
.) See Semantic Values of Tokens. In semantic actions, it stores the semantic value of the lookahead token. See Actions.
Macro for specifying the maximum size of the parser stack. See Memory Management.
Global variable which Bison increments each time it reports a syntax error. (In a pure parser, it is a local variable within
yyparse
. In a pure push parser, it is a member of yypstate.) See The Error Reporting Functionyyerror
.
The parser function produced by Bison; call this function to start parsing. See The Parser Function
yyparse
.
Macro used to output token semantic values. For yacc.c only. Obsoleted by
%printer
. See TheYYPRINT
Macro.
The function to delete a parser instance, produced by Bison in push mode; call this function to delete the memory associated with a parser. See The Parser Delete Function
yypstate_delete
. (The current push parsing interface is experimental and may evolve. More user feedback will help to stabilize it.)
The function to create a parser instance, produced by Bison in push mode; call this function to create a new parser. See The Parser Create Function
yypstate_new
. (The current push parsing interface is experimental and may evolve. More user feedback will help to stabilize it.)
The parser function produced by Bison in push mode; call this function to parse the rest of the input stream. See The Pull Parser Function
yypull_parse
. (The current push parsing interface is experimental and may evolve. More user feedback will help to stabilize it.)
The parser function produced by Bison in push mode; call this function to parse a single token. See The Push Parser Function
yypush_parse
. (The current push parsing interface is experimental and may evolve. More user feedback will help to stabilize it.)
An obsolete macro for specifying the name of a parameter that
yyparse
should accept. The use of this macro is deprecated, and is supported only for Yacc like parsers. See Calling Conventions for Pure Parsers.
The expression
YYRECOVERING ()
yields 1 when the parser is recovering from a syntax error, and 0 otherwise. See Special Features for Use in Actions.
Macro used to control the use of
alloca
when the deterministic parser in C needs to extend its stacks. If defined to 0, the parser will usemalloc
to extend its stacks. If defined to 1, the parser will usealloca
. Values other than 0 and 1 are reserved for future Bison extensions. If not defined,YYSTACK_USE_ALLOCA
defaults to 0.In the all-too-common case where your code may run on a host with a limited stack and with unreliable stack-overflow checking, you should set
YYMAXDEPTH
to a value that cannot possibly result in unchecked stack overflow on any of your target hosts whenalloca
is called. You can inspect the code that Bison generates in order to determine the proper numeric values. This will require some expertise in low-level implementation details.