[unix-history] / usr / man / man1 / yacc.1

.TH YACC 1 
.SH NAME
yacc \- yet another compiler-compiler
.SH SYNOPSIS
.B yacc
[
.B \-vd
]
grammar
.SH DESCRIPTION
.I Yacc
converts a context-free grammar into a set of
tables for a simple automaton which executes an LR(1) parsing
algorithm.
The grammar may be ambiguous;
specified precedence rules are used to break ambiguities.
.PP
The output file,
.IR y.tab.c ,
must be compiled by the C compiler
to produce a program
.IR yyparse .
This program must be loaded with the lexical analyzer program,
.IR yylex ,
as well as
.I main
and
.IR yyerror ,
an error handling routine.
These routines must be supplied by the user;
.IR Lex (1)
is useful for creating lexical analyzers usable by
.IR yacc .
.PP
If the
.B \-v
flag is given, the file
.I y.output
is prepared, which contains a description of the parsing tables
and a report on
conflicts generated by ambiguities in the grammar.
.PP
If the \-\fBd\fR flag is used, the file
.I y.tab.h
is generated with the
.I define
statements that associate the
.I yacc\c
-assigned `token codes' with the user-declared `token names'.
This allows source files other than
.I y.tab.c
to access the token codes.
.SH FILES
.ta \w'yacc.tmp, yacc.acts 'u
y.output
.br
y.tab.c
.br
y.tab.h	defines for token names
.br
yacc.tmp, yacc.acts	temporary files
.br
/usr/lib/yaccpar	parser prototype for C programs
.br
/lib/liby.a	library with default `main' and `yyerror'
.SH "SEE ALSO"
.IR lex (1)
.br
.I "LR Parsing"
by A. V. Aho and S. C. Johnson,
Computing Surveys, June, 1974.
.br
.I "YACC \- Yet Another Compiler Compiler"
by S. C. Johnson.
.SH DIAGNOSTICS
The number of reduce-reduce and shift-reduce conflicts
is reported on the standard output;
a more detailed report is
found in the
.I y.output
file.
Similarly, if some rules are not reachable from the
start symbol, this is also reported.
.SH BUGS
Because file names are fixed, at most one
.I yacc
process can be active in a given directory at
a time.
Commit	Line	Data
6a99ffcf SJ	1	.TH YACC 1
	2	.SH NAME
	3	yacc \- yet another compiler-compiler
	4	.SH SYNOPSIS
	5	.B yacc
	6	[
	7	.B \-vd
	8	]
	9	grammar
	10	.SH DESCRIPTION
	11	.I Yacc
	12	converts a context-free grammar into a set of
	13	tables for a simple automaton which executes an LR(1) parsing
	14	algorithm.
	15	The grammar may be ambiguous;
	16	specified precedence rules are used to break ambiguities.
	17	.PP
	18	The output file,
	19	.IR y.tab.c ,
	20	must be compiled by the C compiler
	21	to produce a program
	22	.IR yyparse .
	23	This program must be loaded with the lexical analyzer program,
	24	.IR yylex ,
	25	as well as
	26	.I main
	27	and
	28	.IR yyerror ,
	29	an error handling routine.
	30	These routines must be supplied by the user;
	31	.IR Lex (1)
	32	is useful for creating lexical analyzers usable by
	33	.IR yacc .
	34	.PP
	35	If the
	36	.B \-v
	37	flag is given, the file
	38	.I y.output
	39	is prepared, which contains a description of the parsing tables
	40	and a report on
	41	conflicts generated by ambiguities in the grammar.
	42	.PP
	43	If the \-\fBd\fR flag is used, the file
	44	.I y.tab.h
	45	is generated with the
	46	.I define
	47	statements that associate the
	48	.I yacc\c
	49	-assigned `token codes' with the user-declared `token names'.
	50	This allows source files other than
	51	.I y.tab.c
	52	to access the token codes.
	53	.SH FILES
	54	.ta \w'yacc.tmp, yacc.acts 'u
	55	y.output
	56	.br
	57	y.tab.c
	58	.br
	59	y.tab.h defines for token names
	60	.br
	61	yacc.tmp, yacc.acts temporary files
	62	.br
	63	/usr/lib/yaccpar parser prototype for C programs
	64	.br
65	/lib/liby.a library with default `main' and `yyerror'
66	.SH "SEE ALSO"
67	.IR lex (1)
68	.br
69	.I "LR Parsing"
70	by A. V. Aho and S. C. Johnson,
71	Computing Surveys, June, 1974.
72	.br
73	.I "YACC \- Yet Another Compiler Compiler"
74	by S. C. Johnson.
75	.SH DIAGNOSTICS
76	The number of reduce-reduce and shift-reduce conflicts
77	is reported on the standard output;
78	a more detailed report is
79	found in the
80	.I y.output
81	file.
82	Similarly, if some rules are not reachable from the
83	start symbol, this is also reported.
84	.SH BUGS
85	Because file names are fixed, at most one
86	.I yacc
87	process can be active in a given directory at
88	a time.