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Bison Symbols
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
containing an error may be recognized as valid. On a parse error, the
token
error
becomes the current look-ahead token. Actions
corresponding to error
are then executed, and the look-ahead
token is reset to the token that originally caused the violation.
See Error Recovery.
YYABORT
- Macro to pretend that an unrecoverable syntax error has occurred, by
making
yyparse
return 1 immediately. The error reporting
function yyerror
is not called. See The Parser Function yyparse
.
YYACCEPT
- Macro to pretend that a complete utterance of the language has been
read, by making
yyparse
return 0 immediately.
See The Parser Function yyparse
.
YYBACKUP
- Macro to discard a value from the parser stack and fake a look-ahead
token. See Special Features for Use in Actions.
YYERROR
- Macro to pretend that a syntax error has just been detected: call
yyerror
and then perform normal error recovery if possible
(see Error Recovery), or (if recovery is impossible) make
yyparse
return 1. See Error Recovery.
YYERROR_VERBOSE
- Macro that you define with
#define
in the Bison declarations
section to request verbose, specific error message strings when
yyerror
is called.
YYINITDEPTH
- Macro for specifying the initial size of the parser stack.
See Stack Overflow.
YYLEX_PARAM
- Macro for specifying an extra argument (or list of extra arguments) for
yyparse
to pass to yylex
. See Calling Conventions for Pure Parsers.
YYLTYPE
- Macro for the data type of
yylloc
; a structure with four
members. See Data Types of Locations.
yyltype
- Default value for YYLTYPE.
YYMAXDEPTH
- Macro for specifying the maximum size of the parser stack.
See Stack Overflow.
YYPARSE_PARAM
- Macro for specifying the name of a parameter that
yyparse
should
accept. See Calling Conventions for Pure Parsers.
YYRECOVERING
- Macro whose value indicates whether the parser is recovering from a
syntax error. See Special Features for Use in Actions.
YYSTACK_USE_ALLOCA
- Macro used to control the use of
alloca
. If defined to 0
,
the parser will not use alloca
but malloc
when trying to
grow its internal stacks. Do not define YYSTACK_USE_ALLOCA
to anything else.
YYSTYPE
- Macro for the data type of semantic values;
int
by default.
See Data Types of Semantic Values.
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
yyparse
.) Error-recovery rule actions may examine this variable.
See Special Features for Use in Actions.
yyclearin
- Macro used in error-recovery rule actions. It clears the previous
look-ahead token. See Error Recovery.
yydebug
- 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 Debugging Your Parser.
yyerrok
- Macro to cause parser to recover immediately to its normal mode
after a parse error. See Error Recovery.
yyerror
- User-supplied function to be called by
yyparse
on error. The
function receives one argument, a pointer to a character string
containing an error message. See The Error Reporting Function yyerror
.
yylex
- User-supplied lexical analyzer function, called with no arguments
to get the next token. See The Lexical Analyzer Function
yylex
.
yylval
- External variable in which
yylex
should place the semantic
value associated with a token. (In a pure parser, it is a local
variable within yyparse
, and its address is passed to
yylex
.) See Semantic Values of Tokens.
yylloc
- 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 within yyparse
, and its address is passed to
yylex
.) You can ignore this variable if you don't use the
@
feature in the grammar actions. See Textual Positions of Tokens.
yynerrs
- Global variable which Bison increments each time there is a parse error.
(In a pure parser, it is a local variable within
yyparse
.)
See The Error Reporting Function yyerror
.
yyparse
- The parser function produced by Bison; call this function to start
parsing. See The Parser Function
yyparse
.
%debug
- Equip the parser for debugging. See Decl Summary.
%defines
- Bison declaration to create a header file meant for the scanner.
See Decl Summary.
%file-prefix="prefix"
- Bison declaration to set tge prefix of the output files. See Decl Summary.
%left
- Bison declaration to assign left associativity to token(s).
See Operator Precedence.
%name-prefix="prefix"
- Bison declaration to rename the external symbols. See Decl Summary.
%no-lines
- Bison declaration to avoid generating
#line
directives in the
parser file. See Decl Summary.
%nonassoc
- Bison declaration to assign non-associativity to token(s).
See Operator Precedence.
%output="filename"
- Bison declaration to set the name of the parser file. See Decl Summary.
%prec
- Bison declaration to assign a precedence to a specific rule.
See Context-Dependent Precedence.
%pure-parser
- Bison declaration to request a pure (reentrant) parser.
See A Pure (Reentrant) Parser.
%right
- Bison declaration to assign right associativity to token(s).
See Operator Precedence.
%start
- Bison declaration to specify the start symbol. See The Start-Symbol.
%token
- Bison declaration to declare token(s) without specifying precedence.
See Token Type Names.
%token-table
- Bison declaration to include a token name table in the parser file.
See Decl Summary.
%type
- Bison declaration to declare nonterminals. See Nonterminal Symbols.
%union
- Bison declaration to specify several possible data types for semantic
values. See The Collection of Value Types.
These are the punctuation and delimiters used in Bison input:
%%
- Delimiter used to separate the grammar rule section from the
Bison declarations section or the additional C code section.
See The Overall Layout of a Bison Grammar.
%{ %}
- All code listed between
%{
and %}
is copied directly to
the output file uninterpreted. Such code forms the "C declarations"
section of the input file. See Outline of a Bison Grammar.
/*...*/
- Comment delimiters, as in C.
:
- Separates a rule's result from its components. See Syntax of Grammar Rules.
;
- Terminates a rule. See Syntax of Grammar Rules.
|
- Separates alternate rules for the same result nonterminal.
See Syntax of Grammar Rules.