BISON

NAME
SYNOPSIS
DESCRIPTION
FILES
ENVIRONMENT VARIABLES
SEE ALSO
DIAGNOSTICS

NAME

bison − GNU Project parser generator (yacc replacement)

SYNOPSIS

bison [ −b file-prefix ] [ −−file-prefix=file-prefix ] [ −d ] [ −−defines ] [ −k ] [ −−token-table ] [ −l ] [ −−no-lines ] [ −n ] [ −−no-parser ] [ −o outfile ] [ −−output-file=outfile ] [ −p prefix ] [ −−name-prefix=prefix ] [ −r ] [ −−raw ] [ −t ] [ −−debug ] [ −v ] [ −−verbose ] [ −V ] [ −−version ] [ −y ] [ −−yacc ] [ −h ] [ −−help ] [ −−fixed-output-files ] file

DESCRIPTION

Bison is a parser generator in the style of yacc(1). It should be upwardly compatible with input files designed for yacc.

Input files should follow the yacc convention of ending in .y. Unlike yacc, the generated files do not have fixed names, but instead use the prefix of the input file. For instance, a grammar description file named parse.y would produce the generated parser in a file named parse.tab.c, instead of yacc’s y.tab.c.

This description of the options that can be given to bison is adapted from the node Invocation in the bison.texinfo manual, which should be taken as authoritative.

Bison supports both traditional single-letter options and mnemonic long option names. Long option names are indicated with −− instead of . Abbreviations for option names are allowed as long as they are unique. When a long option takes an argument, like −−file-prefix, connect the option name and the argument with =.

OPTIONS

−b file-prefix

−−file-prefix=file-prefix

Specify a prefix to use for all bison output file names. The names are chosen as if the input file were named file-prefix.c.

−d

−−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.

−r

−−raw

The token numbers in the name.h file are usually the Yacc compatible translations. If this switch is specified, Bison token numbers are output instead. (Yacc numbers start at 257 except for single character tokens; Bison assigns token numbers sequentially for all tokens starting at 3.)

−k

−−token-table

This switch causes the name.tab.c output to include a list of token names in order by their token numbers; this is defined in the array yytname. Also generated are #defines for YYNTOKENS, YYNNTS, YYNRULES, and YYNSTATES.

−l

−−no-lines

Don’t put any #line preprocessor commands in the parser file. Ordinarily bison puts them in the parser file so that the C compiler and debuggers will associate errors with your source file, the grammar file. This option causes them to associate errors with the parser file, treating it an independent source file in its own right.

−n

−−no-parser

Do not generate the parser code into the output; generate only declarations. The generated name.tab.c file will have only constant declarations. In addition, a name.act file is generated containing a switch statement body containing all the translated actions.

−o outfile

−−output-file=outfile

Specify the name outfile for the parser file.

The other output files’ names are constructed from outfile as described under the −v and −d switches.

−p prefix

−−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, yylval, yychar, and yydebug.

For example, if you use −p c, the names become cparse, clex, and so on.

−t

−−debug

Output a definition of the macro YYDEBUG into the parser file, so that the debugging facilities are compiled.

−v

−−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.

−V

−−version

Print the version number of bison and exit.

−h

−−help

Print a summary of the options to bison and exit.

−y

−−yacc

−−fixed-output-files

Equivalent to −o y.tab.c; the parser output file is called y.tab.c, and the other outputs are called y.output and y.tab.h. The purpose of this switch is to imitate yacc’s output file name conventions. Thus, the following shell script can substitute for yacc:

bison −y $*

FILES

/usr/local/lib/bison.simple

simple parser

/usr/local/lib/bison.hairy

complicated parser

ENVIRONMENT VARIABLES

BISON_SIMPLE

If this is set, it specifies the location in which the bison.simple parser can be found.

BISON_HAIRY

If this is set, it specifies the location in which the bison.hairy parser can be found.

SEE ALSO

yacc(1)
The Bison Reference Manual, included as the file bison.texinfo in the bison source distribution.

DIAGNOSTICS

Self explanatory.