yacc.1

<B>Digital的Unix操作系统VAX 4.2源码</B>

.\" SCCSID: @(#)yacc.1	8.1	9/11/90
.\" SCCSID: @(#)yacc.1	8.1	9/11/90
.TH yacc 1 
.SH Name
yacc \- yet another compiler-compiler
.SH Syntax
.B yacc
[\fB\-vd\fR] \fIgrammar\fR
.SH Description
.NXR "yacc compiler"
.NXA "yacc compiler" "lex program generator"
.NXR "compiler" "creating"
The
.PN yacc
command converts a context-free grammar into a set of
tables for a simple automaton which executes an
left recursive parsing algorithm.
The grammar may be ambiguous;
specified precedence rules are used to break ambiguities.
.PP
The output file, 
.PN 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; 
.PN lex(1)
is useful for creating lexical analyzers usable by
.PN yacc .
.SH Options
.IP \fB\-d\fR 0.3i
Writes all define statements to 
.PN y.tab.h
file.  This allows source files other than 
.PN y.tab.c
to access the token codes.
.IP \fB\-v\fR 0.3i
Writes description of parsing tables and report
of grammatical conflicts to
.PN y.output
file.  
.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 
.PN y.output file .
Similarly, if some rules are not reachable from the
start symbol, this is also reported.
.SH Restrictions
Because file names are fixed, at most one
.PN yacc
process can be active in a given directory at
a time.
.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
.SH See Also
lex(1)
.br
"YACC \- Yet Another Compiler Compiler"
.I ULTRIX Supplementary Documents
Vol. II:Programmer