Bison Declaration Summary ------------------------- Here is a summary of the declarations used to define a grammar: `%union' Declare the collection of data types that semantic values may have (Note: The Collection of Value Types.). `%token' Declare a terminal symbol (token type name) with no precedence or associativity specified (Note: Token Type Names.). `%right' Declare a terminal symbol (token type name) that is right-associative (Note: Operator Precedence.). `%left' Declare a terminal symbol (token type name) that is left-associative (Note: Operator Precedence.). `%nonassoc' Declare a terminal symbol (token type name) that is nonassociative (using it in a way that would be associative is a syntax error) (Note: Operator Precedence.). `%type' Declare the type of semantic values for a nonterminal symbol (Note: Nonterminal Symbols.). `%start' Specify the grammar's start symbol (Note: The Start-Symbol. ). `%expect' Declare the expected number of shift-reduce conflicts (Note: Suppressing Conflict Warnings.). In order to change the behavior of `bison', use the following directives: `%debug' In the parser file, define the macro `YYDEBUG' to 1 if it is not already defined, so that the debugging facilities are compiled. Note: Debugging Your Parser. `%defines' Write an extra output file containing macro definitions for the token type names defined in the grammar and the semantic value type `YYSTYPE', as well as a few `extern' variable declarations. If the parser output file is named `NAME.c' then this file is named `NAME.h'. This output file is essential if you wish to put the definition of `yylex' in a separate source file, because `yylex' needs to be able to refer to token type codes and the variable `yylval'. Note: Semantic Values of Tokens. `%file-prefix="PREFIX"' Specify a prefix to use for all Bison output file names. The names are chosen as if the input file were named `PREFIX.y'. `%locations' Generate the code processing the locations (Note: Special Features for Use in Actions.). This mode is enabled as soon as the grammar uses the special `@N' tokens, but if your grammar does not use it, using `%locations' allows for more accurate parse error messages. `%name-prefix="PREFIX"' Rename the external symbols used in the parser so that they start with PREFIX instead of `yy'. The precise list of symbols renamed is `yyparse', `yylex', `yyerror', `yynerrs', `yylval', `yychar' and `yydebug'. For example, if you use `%name-prefix="c_"', the names become `c_parse', `c_lex', and so on. Note: Multiple Parsers in the Same Program. `%no-parser' Do not include any C code in the parser file; generate tables only. The parser file contains just `#define' directives and static variable declarations. This option also tells Bison to write the C code for the grammar actions into a file named `FILENAME.act', in the form of a brace-surrounded body fit for a `switch' statement. `%no-lines' Don't generate any `#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. `%output="FILENAME"' Specify the FILENAME for the parser file. `%pure-parser' Request a pure (reentrant) parser program (Note: A Pure (Reentrant) Parser.). `%token_table' Generate an array of token names in the parser file. The name of the array is `yytname'; `yytname[I]' is the name of the token whose internal Bison token code number is I. The first three elements of `yytname' are always `"$"', `"error"', and `"$illegal"'; after these come the symbols defined in the grammar file. For single-character literal tokens and literal string tokens, the name in the table includes the single-quote or double-quote characters: for example, `"'+'"' is a single-character literal and `"\"<=\""' is a literal string token. All the characters of the literal string token appear verbatim in the string found in the table; even double-quote characters are not escaped. For example, if the token consists of three characters `*"*', its string in `yytname' contains `"*"*"'. (In C, that would be written as `"\"*\"*\""'). When you specify `%token_table', Bison also generates macro definitions for macros `YYNTOKENS', `YYNNTS', and `YYNRULES', and `YYNSTATES': `YYNTOKENS' The highest token number, plus one. `YYNNTS' The number of nonterminal symbols. `YYNRULES' The number of grammar rules, `YYNSTATES' The number of parser states (Note: Parser States). `%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. This file also describes all the conflicts, both those resolved by operator precedence and the unresolved ones. The file's name is made by removing `.tab.c' or `.c' from the parser output file name, and adding `.output' instead. Therefore, if the input file is `foo.y', then the parser file is called `foo.tab.c' by default. As a consequence, the verbose output file is called `foo.output'. `%yacc' `%fixed-output-files' Pretend the option `--yacc' was given, i.e., imitate Yacc, including its naming conventions. Note: Bison Options, for more.
Dirfile and infopages generated Sat Dec 3 02:07:54 2005