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
=.
- -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:
The long-named options can be introduced with `+' as well as `--',
for compatibility with previous releases. Eventually support for `+'
will be removed, because it is incompatible with the POSIX.2 standard.