NAME
yacc
- an
LALR(1)
parser generator
SYNOPSIS
yacc
[-dlrtv]
[-b prefix]
[-o outputfile]
[-p symbol_prefix]
filename
DESCRIPTION
yacc
reads the grammar specification in the file
filename
and generates an
LR(1)
parser for it.
The parsers consist of a set of
LALR(1)
parsing tables and a driver routine
written in the C programming language.
yacc
normally writes the parse tables and the driver routine to the file
y.tab.c
.
The following options are available:
- -b prefix
-
The
-b
option changes the prefix prepended to the output file names to
the string denoted by
prefix.
The default prefix is the character
y.
- -d
-
The
-d
option causes the header file
y.tab.h
to be written.
- -l
-
If the
-l
option is not specified,
yacc
will insert #line directives in the generated code.
The #line directives let the C compiler relate errors in the
generated code to the user's original code.
If the
-l
option is specified,
yacc
will not insert the #line directives.
#line directives specified by the user will be retained.
- -o outputfile
-
The
-o
option specifies an explicit output file name should be used instead
of the default.
- -p symbol_prefix
-
The
-p
option changes the prefix prepended to yacc-generated symbols to
the string denoted by
symbol_prefix.
The default prefix is the string
yy.
- -r
-
The
-r
option causes
yacc
to produce separate files for code and tables.
The code file is named
y.code.c
,
and the tables file is named
y.tab.c
.
- -t
-
The
-t
option changes the preprocessor directives generated by
yacc
so that debugging statements will be incorporated in the compiled code.
- -v
-
The
-v
option causes a human-readable description of the generated parser to
be written to the file
y.output
.
ENVIRONMENT
The following environment variable is referenced by
:
TMPDIR
-
If the environment variable
TMPDIR
is set, the string denoted by
TMPDIR
will be used as the name of the directory where the temporary
files are created.
TABLES
The names of the tables generated by this version of
yacc
are
``yylhs'',
``yylen'',
``yydefred'',
``yydgoto'',
``yysindex'',
``yyrindex'',
``yygindex'',
``yytable'',
and
``yycheck''.
Two additional tables,
``yyname''
and
``yyrule'',
are created if
YYDEBUG
is defined and non-zero.
FILES
y.code.c
-
y.tab.c
-
y.tab.h
-
y.output
-
/tmp/yacc.aXXXXXX
-
/tmp/yacc.tXXXXXX
-
/tmp/yacc.uXXXXXX
-
DIAGNOSTICS
If there are rules that are never reduced, the number of such rules is
written to the standard error.
If there are any
LALR(1)
conflicts, the number of conflicts is also written
to the standard error.
STANDARDS
The
yacc
utility conforms to
IEEE Std 1003.2 (``POSIX.2'') .