YACC(1) MidnightBSD General Commands Manual YACC(1)

NAME

yacc — an LALR(1) parser generator

SYNOPSIS

yacc [−dlrtv] [−b file_prefix] [−o output_filename] [−p symbol_prefix] filename

DESCRIPTION

The yacc utility 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. The yacc utility normally writes the parse tables and the driver routine to the file y.tab.c.

The following options are available:

−b file_prefix

Change the prefix prepended to the output file names to the string denoted by file_prefix. The default prefix is the character y.

−d

Cause 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. Any #line directives specified by the user will be retained.

−o output_filename

Cause yacc to write the generated code to output_filename instead of the default file, y.tab.c.

−p symbol_prefix

Change the prefix prepended to yacc-generated symbols to the string denoted by symbol_prefix. The default prefix is the string yy.

−r

Cause 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

Change the preprocessor directives generated by yacc so that debugging statements will be incorporated in the compiled code.

−v

Cause a human-readable description of the generated parser to be written to the file y.output.

ENVIRONMENT
TMPDIR

Name of directory where temporary files are to be 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.aXXXXXXXXXX
/tmp/yacc.tXXXXXXXXXX
/tmp/yacc.uXXXXXXXXXX
DIAGNOSTICS

If there are rules that are never reduced, the number of such rules is reported on standard error. If there are any LALR(1) conflicts, the number of conflicts is reported on standard error.

SEE ALSO

yyfix(1)

STANDARDS

The yacc utility conforms to IEEE Std 1003.2 (‘‘POSIX.2’’).

HISTORY

A yacc command appeared in PWB UNIX.

MidnightBSD 0.3 May 24, 1993 MidnightBSD 0.3