2.11BSD#431 - /usr/man/cat1/yacc.0

YACC(1)             UNIX Programmer's Manual		  YACC(1)


NAME
     yacc - yet another compiler-compiler

SYNOPSIS
     yacc [ -vd ] grammar

DESCRIPTION
     Yacc converts a context-free grammar into a set of tables
     for a simple automaton which executes an LR(1) parsing algo-
     rithm.  The grammar may be ambiguous; specified precedence
     rules are used to break ambiguities.

     The output file, y.tab.c, must be compiled by the C compiler
     to produce a program yyparse.  This program must be loaded
     with the lexical analyzer program, yylex, as well as main
     and yyerror, an error handling routine.  These routines must
     be supplied by the user; Lex(1) is useful for creating lexi-
     cal analyzers usable by yacc.

     If the -v flag is given, the file y.output is prepared,
     which contains a description of the parsing tables and a
     report on conflicts generated by ambiguities in the grammar.

     If the -d flag is used, the file y.tab.h is generated with
     the define statements that associate the yacc-assigned
     `token codes' with the user-declared `token names'.  This
     allows source files other than y.tab.c to access the token
     codes.

FILES
     y.output
     y.tab.c
     y.tab.h		 defines for token names
     yacc.tmp, yacc.acts temporary files
     /usr/share/misc/yaccparparser prototype for C programs

SEE ALSO
     lex(1)
     LR Parsing by A. V. Aho and S. C. Johnson, Computing Sur-
     veys, June, 1974.
     YACC - Yet Another Compiler Compiler by S. C. Johnson.

DIAGNOSTICS
     The number of reduce-reduce and shift-reduce conflicts is
     reported on the standard output; a more detailed report is
     found in the y.output file.  Similarly, if some rules are
     not reachable from the start symbol, this is also reported.

BUGS
     Because file names are fixed, at most one yacc process can
     be active in a given directory at a time.


Printed 11/26/99	October 22, 1996			1