Newsgroups: fj.lang.misc
Path: galaxy.trc.rwcp.or.jp!coconuts.jaist!wnoc-tyo-news!wnoc-sfc-news!wnoc-kyo-news!hakozaki.karrn!siebold!calloway-asy-12.rutgers.edu!kenn
From: kenn@calloway-asy-12.rutgers.edu (Ken Nakata)
Subject: Re: How to describe rule for YACC&LEX.
Message-ID: <1996Feb23.201947.18877@siebold.cc.nagasaki-u.ac.jp>
Sender: news@siebold.cc.nagasaki-u.ac.jp (news)
Reply-To: kenn@eden.rutgers.edu
Organization: Rutgers - The State University of New Jersey
References: <4g25ad$1i2@fu.bekkoame.or.jp> <4gbvik$i9s@engr.orst.edu> <1996Feb20.125454.25899@siebold.cc.nagasaki-u.ac.jp> <KATE.96Feb23211755@yamato.trad.pfu.fujitsu.co.jp>
Date: Fri, 23 Feb 1996 20:19:47 GMT
Lines: 102
Xref: galaxy.trc.rwcp.or.jp fj.lang.misc:1571
X-originally-archived-at: http://galaxy.rwcp.or.jp/text/cgi-bin/newsarticle2?ng=fj.lang.misc&nb=1571&hd=a
X-reformat-date: Mon, 18 Oct 2004 15:18:22 +0900
X-reformat-comment: Tabs were expanded into 4 column tabstops by the Galaxy's archiver. See http://katsu.watanabe.name/ancientfj/galaxy-format.html for more info.

$BJR;3$5$s!"%U%)%m!<$"$j$,$H$&$4$6$$$^$9!#(B

In article <KATE.96Feb23211755@yamato.trad.pfu.fujitsu.co.jp>,
KATAYAMA Yoshio <kate@pfu.fujitsu.co.JP> wrote:
] In article <1996Feb20.125454.25899@siebold.cc.nagasaki-u.ac.jp>,
] kenn@quincy-asy-5.rutgers.edu (Ken Nakata) writes:
] >%token ATOM
] >%left SELECT
] >%left CONCAT
] >%%
] >regexps: regexps SELECT regexps
] >| regexps ATOM %prec CONCAT
] >| ATOM
] >;
] >%%
] 
] shift/reduce conflict $B$,5/$-$k>l9g$O!"0lJ}$N5,B'$,=*C<5-9f$rFI$b(B
] $B$&$H$7$F$$$k>uBV$H!"B>J}$N5,B'$,!J$=$N5,B'Cf$N!K5-9f$rA4ItFI$s$@(B
] $B>uBV$K$J$C$F$^$9!#$3$NNc$N>l9g$N(B y.output $B$G$O!"(B
] 
] 5: shift/reduce conflict (shift 4, red'n 1) on ATOM
] state 5
] regexps :  regexps_SELECT regexps 
] regexps :  regexps SELECT regexps_     (1)
] regexps :  regexps_ATOM 
] 
] ATOM  shift 4
] .  reduce 1
] 
] $B$N>uBV!J#3HVL\$H#2HVL\$,>WFM!K$G$9!#(B

Berkeley yacc $B$@$H!"(B

5: shift/reduce conflict (shift 3, reduce 1) on ATOM
state 5
regexps : regexps . SELECT regexps  (1)
regexps : regexps SELECT regexps .  (1)
regexps : regexps . ATOM  (2)

ATOM  shift 3
$end  reduce 1
SELECT  reduce 1

$B$N$h$&$K$J$j$^$9!#$3$N%"%/%7%g%s$NItJ,$@$18+$k8B$j(B conflict $B$J$s$F5/$-(B
$B$F$$$J$$$h$&$K$b8+$($k$s$G$9$,!"$G$b2?8N$+J86g$O8@$C$F$^$9!#(B

] $B$3$N$H$-!"M%@h=g0L$NHf3S$O!"(B
] 
] shift: $B<!$KMh$k=*C<5-9f(B
] red'n: $B:G8e$N=*C<5-9f(B
] 
] $B$G9T$J$o$l$^$9!#(B

$B$3$3$,$h$/$o$+$i$J$$$N$G$9$,!"!V<!$KMh$k=*C<5-9f!W$H$$$&$N$O(B lookahead 
$B$N$3$H$G$9$h$M!)(B $B$G$O!V:G8e$N=*C<5-9f!W$H$$$&$N$O2?$N$3$H$G$7$g$&$+!)(B
$B%9%?%C%/$K@Q$^$l$?=*C<5-9f$NCf$G0lHV%H%C%W$K6a$$0LCV$K$"$k$b$N$G$9$+!)(B
$B;d$,M}2r$7$F$$$kHO0O$G$O!"(Byacc $B$N(B PDA $B$N<!$NF0:n$O%9%?%C%/%H%C%W$K$"$k(B 
state $B$H(B lookahead $B$@$1$G7h$^$k$H;W$C$?$N$G$9$,!D!#0c$$$^$7$?$C$1!)(B $B$G(B
$B$9$+$i!">e$N(B($BJR;3$5$s$N(B) y.output $B$NFI$_J}$O!"!V(Bstate 5 $B$G$O(B lookahead 
$B$,(B ATOM $B$N;~$O(B lookahead $B$r%9%?%C%/$K@Q$s$G(B state 4 $B$X0\$k!"$^$?(B 
lookahead $B$K4X78$J$/%k!<%k(B 1 $B$K$h$k(B reduction $B$r9T$&!W$H$$$&$b$N$@$H;W$C(B
$B$F$$$^$7$?!#(B

$B2?$+4V0c$$$,$"$l$P$4;XE&$/$@$5$$!#(B

# $B0lJ}(B goto $BF0:n$H$$$&$N$b$"$C$F!"$3$l$O(B reduction $B$r$d$C$?8e$K!"%9%?%C(B
# $B%/%H%C%W$K;D$C$F$$$k(B state $B$H(B reduction $B$N7k2L$NHs=*C<5-9f(B($B;HMQ$7$?(B
# $B%k!<%k$N:8JUCM(B)$B$+$i<!$N(B state $B$r7h$a$k(B(push $B$9$k(B)$BF0:n!"$HM}2r$7$F$*(B
# $B$j$^$9!#(B

] %prec $BIU$-$N5,B'$G$O!"$=$N>l=j$K(B %prec $B$G;XDj$5$l$?=*C<5-9f$,$"(B
] $B$k$b$N$H$7$FHf3S$5$l$^$9!#$D$^$j!"M%@h=g0L$NHf3S$@$1$K$D$$$F$$$((B
] $B$P!"(B%prec $B$,$J$/!"$=$l$G;XDj$5$l$?=*C<5-9f$@$1$,=q$+$l$?>l9g$HF1(B
] $B$8$K$J$j$^$9!#(B

$B$*$C$7$c$k$3$H$O$o$+$j$^$9$,!"$=$l$@$H:#EY$O!"(Brule 2 $B$r(B

regexps : regexps CONCAT ATOM

$B$KJQ$($k$H2?8N(B conflict $B$,=P$J$$$N$+$A$g$C$HIT;W5D$G$9!#(BCONCAT $B1i;;;R(B
$B$r;HMQ$7$J$$>l9g$HF1MM!"M%@hEY$N>pJs$,$J$1$l$P[#Kf$5$r2r>C$G$-$J$$$h$&(B
$B$K;W$&$N$G$9$,!D!#$=$l$K!"(BCONCAT $B$,M%@hEY$r<($9$?$a$@$1$K;H$o$l$F$$$k(B
$B>l9g$bM%@hEY$N>pJs$K$h$C$F[#Kf$5$r2r>C$G$-$k$N$K!"$=$l$G$b(B conflict $B$r(B
$BJs9p$9$k$N$O!"$d$O$jJQ$J46$8$,$7$^$9!#(B

# $B7k6IG<F@$G$-$F$^$;$s$M!#F,$,0-$$$@$1$+$b(B

] $B:#$^$G$K!"$3$N2r<a$+$i30$l$?F0$-$O7P83$7$F$$$^$;$s$,!"!V0c$C$F$$(B
] $B$?$i@UG$$r<h$l$k$N$+!W$H8@$o$l$k$H:$$C$F$7$^$&$N$G$"$j$^$9!#(B(_ _)

$B$$$(!"@UG$$O(B yacc $B$N:n<T(B(pcc $B$N(B Steve Johnson $B$G$9$h$M(B)$B$K<h$C$F$b$i$$(B
$B$^$7$g$&(B :-)

# $B7k6I%=!<%9$rFI$a!"$H$$$&$3$H$K$J$k$N$+$bCN$l$^$;$s$,!"(Byacc $B$N%=!<%9(B
# $BFI$`$N$C$FBgJQ$=$&$@$J$!(B

$BCfED(B $B7r(B <kenn@eden.rutgers.edu>
-- 
"He who refuses to do arithmetic is doomed to talk nonsense." -- John McCarthy
 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
http://remus.rutgers.edu/~kenn/, ftp://remus.rutgers.edu/pub/NetBSD/index.html
Ken Nakata  . . . . Cook College, Rutgers - The State University of New Jersey
