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1 .\" $OpenBSD: yacc.1,v 1.32 2016/07/27 20:53:47 tedu Exp $
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3 .\" Copyright (c) 1989, 1990 The Regents of the University of California.
4 .\" All rights reserved.
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6 .\" This code is derived from software contributed to Berkeley by
7 .\" Robert Paul Corbett.
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33 .\" from: @(#)yacc.1 5.7 (Berkeley) 7/30/91
34 .\"
35 .Dd $Mdocdate: July 27 2016 $
36 .Dt YACC 1
37 .Os
38 .Sh NAME
39 .Nm yacc
40 .Nd an LALR(1) parser generator
41 .Sh SYNOPSIS
42 .Nm yacc
43 .Op Fl dlrtv
44 .Op Fl b Ar file_prefix
45 .Op Fl o Ar output_file
46 .Op Fl p Ar symbol_prefix
47 .Ar file
48 .Sh DESCRIPTION
49 .Nm
50 reads the grammar specification in
51 .Ar file
52 and generates an LR(1) parser for it.
53 The parsers consist of a set of LALR(1)
54 parsing tables and a driver routine
55 written in the C programming language.
56 .Nm
57 normally writes the parse tables and the driver routine to the file
58 .Pa y.tab.c .
59 .Pp
60 The options are as follows:
61 .Bl -tag -width Ds
62 .It Fl b Ar file_prefix
63 The
64 .Fl b
65 option changes the prefix prepended to the output file names to
66 the string denoted by
67 .Ar file_prefix .
68 The default prefix is the character
69 .Ar y .
70 .It Fl d
71 The
72 .Fl d
73 option causes the header file
74 .Pa y.tab.h
75 to be written.
76 .It Fl l
77 If the
78 .Fl l
79 option is not specified,
80 .Nm
81 will insert #line directives in the generated code.
82 The #line directives let the C compiler relate errors in the
83 generated code to the user's original code.
84 If the
85 .Fl l
86 option is specified,
87 .Nm
88 will not insert the #line directives.
89 #line directives specified by the user will be retained.
90 .It Fl o Ar output_file
91 The
92 .Fl o
93 option specifies an explicit name for the parser's output file name instead
94 of the default.
95 The names of the other output files are constructed from
96 .Pa output_file
97 as described under the
98 .Fl d
99 and
100 .Fl v
101 options.
102 .It Fl p Ar symbol_prefix
103 The
104 .Fl p
105 option changes the prefix prepended to yacc-generated symbols to
106 the string denoted by
107 .Ar symbol_prefix .
108 The default prefix is the string
109 .Ar yy .
110 .It Fl r
111 The
112 .Fl r
113 option causes
114 .Nm
115 to produce separate files for code and tables.
116 The code file is named
117 .Pa y.code.c ,
118 and the tables file is named
119 .Pa y.tab.c .
120 .It Fl t
121 The
122 .Fl t
123 option changes the preprocessor directives generated by
124 .Nm
125 so that debugging statements will be incorporated in the compiled code.
126 .It Fl v
127 The
128 .Fl v
129 option causes a human-readable description of the generated parser to
130 be written to the file
131 .Pa y.output .
132 .El
133 .Sh TABLES
134 The names of the tables generated by this version of
135 .Nm
136 are
137 .Dq yylhs ,
138 .Dq yylen ,
139 .Dq yydefred ,
140 .Dq yydgoto ,
141 .Dq yysindex ,
142 .Dq yyrindex ,
143 .Dq yygindex ,
144 .Dq yytable ,
145 and
146 .Dq yycheck .
147 Two additional tables,
148 .Dq yyname
149 and
150 .Dq yyrule ,
151 are created if
152 .Dv YYDEBUG
153 is defined and non-zero.
154 .Sh FILES
155 .Bl -tag -width /tmp/yacc.uXXXXXXXXXX -compact
156 .It Pa y.code.c
157 .It Pa y.tab.c
158 .It Pa y.tab.h
159 .It Pa y.output
160 .It Pa /tmp/yacc.aXXXXXXXXXX
161 .It Pa /tmp/yacc.tXXXXXXXXXX
162 .It Pa /tmp/yacc.uXXXXXXXXXX
163 .El
164 .Sh EXIT STATUS
165 .Ex -std yacc
166 .Sh DIAGNOSTICS
167 If there are rules that are never reduced, the number of such rules is
168 written to the standard error.
169 If there are any LALR(1)
170 conflicts, the number of conflicts is also written
171 to the standard error.
172 .Sh SEE ALSO
173 .Xr yyfix 1
174 .Rs
175 .%A F. DeRemer
176 .%A T. J. Pennello
177 .%D 1982
178 .%J TOPLAS
179 .%N Issue 4
180 .%P pp. 615\(en649
181 .%T Efficient Computation of LALR(1) Look-Ahead Sets
182 .%V Volume 4
183 .Re
184 .Sh STANDARDS
185 The
186 .Nm
187 utility is compliant with the
188 .St -p1003.1-2008
189 specification,
190 though its presence is optional.
191 .Pp
192 The flags
193 .Op Fl or
194 are extensions to that specification.
195 .Sh HISTORY
196 .Nm
197 was originally developed at AT&T by
198 .An Stephen C. Johnson .
199 .Pp
200 Berkeley
201 .Nm
202 was originally developed using PCC on a VAX with the
203 intent of being as compatible as possible with
204 .At
205 .Nm .
206 Much is owed to the unflagging efforts of Keith Bostic.
207 His badgering kept me working on
208 .Nm
209 long after I was ready to quit.
210 .Pp
211 Berkeley
212 .Nm
213 is based on the excellent algorithm for computing
214 LALR(1) lookaheads developed by
215 .An Tom Pennello
216 and
217 .An Frank DeRemer .
218 The algorithm is described in their almost impenetrable article in
219 TOPLAS (see above).
220 .Pp
221 Finally, much credit must go to those who pointed out deficiencies
222 of earlier releases.
223 Among the most prolific contributors were
224 Benson I. Margulies,
225 Dave Gentzel,
226 Antoine Verheijen,
227 Peter S. Housel,
228 Dale Smith,
229 Ozan Yigit,
230 John Campbell,
231 Bill Sommerfeld,
232 Paul Hilfinger,
233 Gary Bridgewater,
234 Dave Bakken,
235 Dan Lanciani,
236 Richard Sargent,
237 and
238 Parag Patel.
239 .Sh AUTHORS
240 The
241 .Nm
242 utility was written by
243 .An Robert Corbett .