Enumerable#gather_each

Tanaka_A · May 10, 2009, 1:14pm

At Sun, 10 May 2009 08:53:31 +0900,
NARUSE, Yui wrote:

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gather_eachã‚ˆã‚Šè¤‡é›‘ã«ãªã£ã¦ã—ã¾ã£ãŸã‚‰ãƒ€ãƒ¡ãªã‚“ã˜ã‚ƒãªã„ã§ã™ã‹ãã€‚

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Enumerableç‰ˆinjectã§ã‚„ã‚‹ã¹ããªæ°—ã‚‚

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yielder ãªã‚Šãã‚Œã‚’åŒ…å«ã™ã‚‹ buffer ãªã‚Šã‚’æ¸¡ã™ã¨ã„ã†APIã¯å¿…è¦ã ã¨
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ã„ã£ãºã‚“ã«å¯èƒ½ã«ã™ã‚‹æ©Ÿèƒ½ã¯ã»ã—ã„ã¨æ€ã£ã¦ã„ã¾ã™ã€‚ãŸã¨ãˆã°ã“ã‚“ãª
æ„Ÿã˜ã§ã™ã€‚

module Enumerable
  def with_yielder(&block)
    Enumerator.new { |yielder|
      each { |x|
        block.call(x, yielder)
      }
    }
  end
end

# æ•´æ•°ã®æ›¸ã„ã¦ã‚ã‚‹è¡Œã‚’æŠ½å‡ºã—ã€æ•°åˆ—ã«ã™ã‚‹
p "abc\n123\n\n456\ndef\n".lines.with_yielder { |line, yielder|
  if m = /^([+\-]?\d+)$/.match(line)
    yielder << m[1].to_i
  end
}.to_a #=> [123, 456]

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Tanaka_A · May 10, 2009, 3:09pm

In article [email protected],
“Akinori MUSHA” [email protected] writes:

e$B!!$7$+$7!“e(B ChangeLog e$B$N$h$&$J>l9g$Oe(B gather_each e$B$bC1=c$5$r0];}e(B
e$B$G$-$:J#?t9T$K$J$k$H;W$$$^$9!#e(Bbuffer e$B$O!”$=$&$7$?>/$7$N0c$$$K$Oe(B
e$B>/$7$N0c$$$GBP1~$G$-$^$9!#e(B

e$B2<$K$"$ke(B ChangeLog e$B$NNc$O!"e(Bslice_before e$B$He(B gather
e$B$r;H$C$F=qe(B
e$B$/$H0J2<$N$h$&$J46$8$K$J$k$G$7$g$&$+!#e(B
(e$B$3$3$G;H$C$F$$$ke(B gather e$B$O!"e(B[ruby-dev:38418]
e$B$N;EMM$G!“e(Bnil
e$B$K$h$j$=$NMWAG$r=|5n$7$^$9!#$=$3$G$Oe(B slice_before e$B$b<BAu$7$Fe(B
e$B$”$j$^$9e(B)

open(“ChangeLog”) {|f|
f.slice_before {|l|
/\A\S/ =~ l
}.each {|h|
header = h.shift
h.gather {|l|
/\A\s*\z/ !~ l
}.each {|entry_lines|
next if /\A\s+*/ !~ entry_lines[0]
puts header, *entry_lines
puts “----”
}
}
}

gather e$B$de(B slice_before e$B$OF~NO$NJB$S$rJQ$($i$l$J$$$N$G!"$3$Ne(B
e$B$h$&$J=hM}$O$3$&$d$C$F2?CJ3,$+$KJ,$1$F$d$k$3$H$K$J$j$^$9$M!#e(B

e$B!!$O$$!#;d$NJ}$Oe(B gather_each e$B$,%+%P!<$G$-$kHO0O$N9-$5$K$D$$$Fe(B
e$B5?Ld$r;}$C$F$$$^$9$,!"FsBr$H$$$&OC$G$O$J$$$H;W$C$F$$$^$9!#e(B

e$B$=$&$G$9$M!#e(B

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e$B$?$H$($P%3!<%IJR$NE&=P$NNc$O<BMQE*$J=hM}$H$7$F407k$7$J$$$N$G!"e(B
gather e$B$NM-MQ$J;HMQNc$H$7$F$O<e$$$N$G$O$J$$$G$7$g$&$+!#e(B

e$B$“$!!”<N$F$J$$$3$H$,=PMh$k!“$H=q$/$Y$-$G$7$?!#e(B
e$B$I$NCM$r<N$F$k0u$K$9$k$+$H$$$&OC$O$”$j$^$9$,!"<N$F$k5!G=$OIUe(B
e$B$1$h$&$H;W$C$F$$$^$9!#e(B

e$B%3!<%IJR$K$D$$$F$O!“%3!<%IJR$Ne(B syntax check e$B$r$d$k$N$G$”$l$Pe(B
e$BB>$O<N$F$F$$$$$G$7$g$&$7!“$^$?!“J8=q$NCf$N%3!<%IJR$re(B
(e$B?'$H$+e(B)
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e$B$G$7$g$&!#MQES<!Bh$G$9$M!#e(B

e$B!!$?$H$($P$G$9$,!"e(B RD e$B$de(B markdown e$B$N$h$&$JJ8=q$r=hM}$9$k>l9g$re(B
e$B9M$($F$$$^$7$?!#9M$($F$_$k$He(B gather e$B$N<iHwHO0O30$+$b$7$l$^$;$s$M!#e(B

RD e$B$Ne(B pre
e$B$O%$%s%G%s%H$,@hF,9T$N?<$50J>e$N$H$3$m$G$9$+$i$M$'!#e(B
buffer e$B$N$h$&$K>e$+$i=hM}$7$F$$$C$?$[$&$,<+A3$+$b!#e(B

e$B$b$7!“%$%s%G%s%H$r@hF,9T$h$j$b@u$/$G$-$k$h$&$J%U%)!<%^%C%H$Ge(B
e$B$”$l$P!“$”$H$+$i$d$C$?$[$&$,$$$$$G$7$g$&$M!#e(B

e$B$b$7!“$I$&$7$F$bJ,N`$NCM$,I,MW$@$H$$$&$3$H$G$”$l$P!“e(Byield e$B$9e(B
e$B$kG[Ns$K%$%s%9%?%s%9JQ?t$H$7$F$D$1$F$*$/e(B (e$BI,MW$J$i$=$l$r;2>He(B
e$B$9$k%”%/%;%5$be(B) e$B$N$K$O$d$V$5$+$G$O$"$j$^$;$s!#e(B

e$B!!$=$N>l9g$Ne(BAPIe$B$O$I$&$J$k$N$G$7$g$&!#e(Bgather e$BK\Mh$NMQES$K$O<YKb$Je(B
e$B%G!<%?$,$/$C$D$$$F$7$^$&$N$G!"JL%a%=%C%I$G$9$+$M!#e(B

ary.category e$B$H$+$G$$$$$s$8$c$J$$$G$7$g$&$+!#G[Ns$K%a%=%C%Ie(B
e$B$,$"$C$?$+$i$C$F<YKb$K$O$J$j$^$;$s$h$M!#e(B

enum.gather { … }.each {|ary| p ary.category }

e$B!!$`$7$m!“EDCf$5$s$N=P$5$l$?e(B2e$BLd$r6qBNNc$H$7$?$H$-$N;d$J$j$N2r$,e(B
Buffer e$B$J$s$G$9$h!#e(Bscanf.rbe$B$+$i$N%3!<%IJR$N@Z$j=P$7$H$$$&:G=i$Ne(B
e$BNc$O!”%3!<%IJR$G$J$$ItJ,$b4^$a$Fe(B pp e$B$9$k$H$$$&$N$,:G=L\E$G$Oe(B
e$B$J$$$G$9$h$M!#:o=|$9$k$H$$$&5!G=$,7g$1$F$$$k$N$GITMW$JItJ,$^$Ge(B
e$BF@$i$l$F$o$:$i$o$7$$!#=>$C$F<h<NA*Br$N5!G=$,I,MW$G$O$J$$$+!"$He(B
e$B;W$$$^$7$?!#e(B

gather e$B$N%V%m%C%/$N$J$K$+$NCM$K:o=|$N5!G=$r3d$jEv$F$h$&$H;We(B
e$B$$$^$9!#e(B

[ruby-dev:38418] e$B$N<BAu$@$H!"e(Bnil, false, :reject
e$B$,:o=|$K$J$Ce(B
e$B$F$^$9!#e(B

e$B!!<!$K%Q%i%0%i%U$4$H$K@Z$k$H$$$&Nc$Oe(B gather_each e$B$,$b$C$H$bC;$/e(B
e$B=q$1$kNc$G$7$?!#$7$+$7$J$,$i!“%X%C%@$r6h@Z$j$H$9$k9=B$$r07$&:]$Oe(B
e$BC;$/$J$/$J$k!#=>$C$FWs0UE*$J%?%$%_%s%0$Ge(B yield e$B$G$-$kI,MW$,$”$k!“e(B
e$B$”$k$$$O>uBV$N4IM}$r;Y1g$9$k$H$$$$$N$G$O$J$$$+!"$H;W$$$^$7$?!#e(B

e$B%X%C%@$r6h@Z$j$H$9$k>l9g$K$OJL%a%=%C%I$Ne(B slice_before e$B$,$$$$e(B
e$B$s$8$c$J$$$+$H;W$$$^$9!#e(B

e$B!!$3$l$i$r9g$o$;$?9M$($?$N$,e(B Buffere$B$G$9!#Ev$?$jA0$G$9$,J#;($J$3$He(B
e$B<+BN$rL;X$7$F$$$k$N$G$O$J$/$F!"e(B gather_each e$B$G$OIT==J,$H46$8!"e(B
e$B0lIt$N%1!<%9$r=|$1$P:GE,$J2r$H$O;W$($J$+$C$?$N$,BP0F$NF05!$G$9!#e(B

e$B$J$k$[$I!#e(B

Unix mbox e$B$N@Z$jJ,$1e(B:

slice_before (slice_by) e$B$K$h$k<BAu$Oe(B [ruby-dev:38407] e$B$K=q$-e(B
e$B$^$7$?$,!"e(Bbuf e$B$N07$$$,ITMW$J$V$se(B slice_before
e$B$N$[$&$,4J7i$Ge(B
e$B$9$M!#e(B

ChangeLog e$B$N3F%(%s%H%j$N@Z$j=P$7e(B:

e$B$3$l$O>e$K=q$-$^$7$?$,!"$b$C$HC;$/=q$1$^$9!#e(B

e$B4JC1$JEEBne(B:

e$B$J$s$Ge(B buffer e$B$r;H$&$s$G$9$+e(B?

STDIN.lines.buffer { |line, buf|
until line.empty?
line.sub!(/\A\s+/, ‘’)
line.sub!(/\A(\d*.?\d+)/) { buf << [:NUM, $1.to_f]; ‘’ }
line.sub!(/\A([+-*/])/) { buf << [:OP, $1.intern]; ‘’ }
end
buf.flush
}.tap { |expr|

e$B$3$l$C$F!“e(B1e$B9T$:$D%H!<%/%s$K$o$1$F!”$=$l$r=hM}$9$k$o$1$G$9$he(B
e$B$M!#e(B

STDIN.each_line {|line|
line e$B$r%H!<%/%s$K$o$1$Fe(B tokens e$B$KF~$l$ke(B
tokens e$B$r7W;;$7$FI=<(e(B
}

e$B$H$$$&$N$G$O$$$1$J$$$s$G$9$+e(B?

Tanaka_A · May 11, 2009, 9:25am

At Sun, 10 May 2009 22:08:55 +0900,
Tanaka A. wrote:

gather ã‚„ slice_before ã¯å…¥åŠ›ã®ä¸¦ã³ã‚’å¤‰ãˆã‚‰ã‚Œãªã„ã®ã§ã€ã“ã®
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ç°¡å˜ãªé›»å“:

ãªã‚“ã§ buffer ã‚’ä½¿ã†ã‚“ã§ã™ã‹?

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Tanaka_A · May 10, 2009, 11:25am

At Sun, 10 May 2009 15:57:33 +0900,
Tanaka A. wrote:

In article [email protected],
“Akinori MUSHA” [email protected] writes:
(snip)

ã€€æœ€åˆã®ä¾‹ã¨ã„ã†ã®ãŒ

arg = lambda {|l| /\A=~ l ? true : nil }
ã§èªã‚ãªã‹ã£ãŸã®ã§ã™ãŒã€ l == “\n” ã§ã—ãŸã‹ã€‚

ã‚ãã€ã™ã„ã¾ã›ã‚“ã€‚ãã“ã¯ /\A\s/ =~ l ã§ã™ã€‚

ãƒ‘ãƒ©ã‚°ãƒ©ãƒ•ã®ä¾‹ã¯æœ€åˆã®ãƒ¡ãƒ¼ãƒ« [ruby-dev:38392] ã®ã‚‚ã†ã¡ã‚‡ã£ã¨
ä¸‹ã«å‡ºã¦ãã¾ã™ã€‚

ã€€ãªã‚‹ã»ã©ã€‚ç©ºè¡Œã¯æ–‡è„ˆä¾å˜ã¨æ€ã£ãŸã®ã§ã™ãŒã€ /\A\s/ ãŒç©ºè¡Œã«ã‚‚
ãƒžãƒƒãƒã—ã¦ãã‚Œã‚‹ã®ã§éƒ½åˆãŒã„ã„ã‚ã‘ã§ã™ãã€‚

ã“ã‚Œã¯
    prev, s.status = s.status, (e == "\n")
    b.flush if prev != b.status
    b << e
ãã‚‰ã„ã§æ‚ªãã¯ãªã„ã¨æ€ã„ã¾ã™ã€‚b.status != nil ã®ã¨ã“ã‚ã¯ã€ä¸Šè¨˜ã®
ã€Œç©ºãªã‚‰ flush ã—ãªã„ã€ã§æ‰‹å½“ã¦ã™ã‚‹ã¨ã—ã¦ã€‚
ãã‚Œã§ã‚‚ gather_each ã®ã»ã†ãŒãšã£ã¨çŸã„ã§ã™ã‚ˆãã€‚

ã€€ã¯ã„ã€ã“ã®ä¾‹ã¯ã¾ã•ã« gather_each ã®å®ˆå‚™ç¯„å›²ã«ã´ã£ãŸã‚Šã§ã™ã€‚

ã€€ã—ã‹ã—ã€ ChangeLog ã®ã‚ˆã†ãªå ´åˆã¯ gather_each ã‚‚å˜ç´”ã•ã‚’ç¶æŒ
ã§ããšè¤‡æ•°è¡Œã«ãªã‚‹ã¨æ€ã„ã¾ã™ã€‚buffer ã¯ã€ãã†ã—ãŸå°‘ã—ã®é•ã„ã«ã¯
å°‘ã—ã®é•ã„ã§å¯¾å¿œã§ãã¾ã™ã€‚

ã€€ã‚„ã‚Šã™ãŽã‹ã‚‚ã—ã‚Œã¾ã›ã‚“ãŒã€ status/status= ã‚’æä¾›ã™ã‚‹ã®ãªã‚‰ã€
prev_status ã‚„ status_changed? ã‚‚ç”¨æ„ã™ã‚‹ã¨ã„ã†æ‰‹ã¯ã‚ã‚Šã¾ã™ã€‚

ç§ã¨ã—ã¦ã¯ã€çŠ¶æ…‹å¤‰åŒ–ã‚’ãƒ¦ãƒ¼ã‚¶ãŒæ„è˜ã™ã‚‹å¿…è¦ã¯ãªã„ç”¨é€”ã¯å……åˆ†ã«
å¤šã„ã¨è€ƒãˆã¦ã„ã¾ã™ã€‚

çŠ¶æ…‹å¤‰åŒ–ã‚’ãã†ã‚„ã£ã¦ã‚µãƒãƒ¼ãƒˆã™ã‚‹ã®ã¯ã€çŠ¶æ…‹å¤‰åŒ–ã‚’ãƒ¦ãƒ¼ã‚¶ãŒæ„è˜
ã™ã‚‹å¿…è¦ãŒã‚ã‚‹ç”¨é€”ã«ã¯æœ‰ç”¨ã§ã—ã‚‡ã†ã€‚ã—ã‹ã—ã€ã¾ãšãã†ã„ã†ç”¨é€”
ãŒå……åˆ†ã«å¤šã„ã®ã‹ã¨ã„ã†ç‚¹ã«ã¤ã„ã¦è°è«–ãŒå¿…è¦ã§ã¯ãªã„ã§ã—ã‚‡ã†ã‹ã€‚

ã€€ã¯ã„ã€‚ç§ã®æ–¹ã¯ gather_each ãŒã‚«ãƒãƒ¼ã§ãã‚‹ç¯„å›²ã®åºƒã•ã«ã¤ã„ã¦
ç–‘å•ã‚’æŒã£ã¦ã„ã¾ã™ãŒã€äºŒæŠžã¨ã„ã†è©±ã§ã¯ãªã„ã¨æ€ã£ã¦ã„ã¾ã™ã€‚

ã€€åŒºåˆ‡ã‚‹ã ã‘ãªã‚‰ç¢ºã‹ã«1è¡Œã§æ¸ˆã¿ã¾ã™ãŒã€å®Ÿéš›ã«ã¯ã‚µãƒ³ãƒ—ãƒ«ã‚³ãƒ¼ãƒ‰è¾ºã‹
ã©ã†ã‹ã‚’åˆ¤å®šã—ãŸã‚Šã€å‰å¾Œã®ç©ºè¡Œã‚’é™¤ã„ãŸã‚Šã¨æœ€çµ‚çµæžœã¾ã§ã®é“ã®ã‚Šã¯
é•·ã„ã®ã§ä½•ã¨ã‚‚è¨€ãˆã¾ã›ã‚“ã€‚è¦ã‚‰ãªã„éƒ¨åˆ†ã¾ã§é›†ã‚ã¦(gather)ã„ã¾ã™ãŒã€
æœ¬å½“ã¯ã‚‚ã£ã¨è¤‡é›‘ãªå‡¦ç†ãŒå¿…è¦ãªã®ã§ buffer ã®ã‚ˆã†ãªã‚‚ã®ãŒã‚ã‚Œã°ã€
å–æ¨ã‚„åŠ å·¥ã«ã¤ã„ã¦ã‚‚å¼•ãå—ã‘ã‚‹ã“ã¨ãŒã§ãã‚‹ã¨æ€ã„ã¾ã—ãŸã€‚

å¾Œã§ã‚„ã‚Œã°ã„ã„ã‚“ã˜ã‚ƒãªã„ã§ã—ã‚‡ã†ã‹ã€‚gather ã¯ã¾ã¨ã‚ã‚‹ã ã‘ã§
æƒ…å ±ã‚’æ¨ã¦ã¾ã›ã‚“ã—ã€‚

ã€€æƒ…å ±ã‚’æ¨ã¦ãªã„ã¨ã™ã‚‹ã¨ã€ã‚«ãƒãƒ¼ç¯„å›²ã¯ã¨ã¦ã‚‚ç‹ããªã‚‹ã¨æ€ã„ã¾ã™ã€‚
ãŸã¨ãˆã°ã‚³ãƒ¼ãƒ‰ç‰‡ã®æ‘˜å‡ºã®ä¾‹ã¯å®Ÿç”¨çš„ãªå‡¦ç†ã¨ã—ã¦å®Œçµã—ãªã„ã®ã§ã€
gather ã®æœ‰ç”¨ãªä½¿ç”¨ä¾‹ã¨ã—ã¦ã¯å¼±ã„ã®ã§ã¯ãªã„ã§ã—ã‚‡ã†ã‹ã€‚

ã€€ä¸Šè¨˜ã®é€šã‚Šã€å®Ÿéš›ã«è€ƒãˆã‚‹ã¹ãã“ã¨ãŒå¾Œã‚ã«æ®‹ã‚‹ã¨æ€ã†ã®ã§ã€ gather
å˜ä½“ã®æä¾›ã™ã‚‹æ©Ÿèƒ½ãŒä¸é€”åŠç«¯ã«æ€ãˆãŸã®ã§ã™ã€‚ã™ãªã‚ã¡ã€ã‚¤ãƒ³ãƒ‡ãƒ³ãƒˆ
ãƒ¬ãƒ™ãƒ«ç‰ã€åˆ†é¡žã®åŸºæº–ã¨ã—ã¦è¨ˆç®—ã—ãŸå€¤(ãƒ–ãƒãƒƒã‚¯ã®è©•ä¾¡å€¤)ã‚’æ¨ã¦ã¦
ã—ã¾ã£ã¦ã„ã¾ã™ãŒã€ã“ã®ä¾‹ã§ã‚‚ã€å¾Œæ®µã§ã¾ãŸå¿…è¦ã«ãªã‚Šãã†ã§ã™ã‚ˆãã€‚

ã‚¤ãƒ³ãƒ‡ãƒ³ãƒˆã®æ·±ã•ã¯ã€ã‚€ã—ã‚å¾Œã‹ã‚‰è¨ˆç®—ã™ã‚‹ã»ã†ãŒã„ã„ã‚“ã˜ã‚ƒãªã„
ã§ã—ã‚‡ã†ã‹ã€‚ã‚¤ãƒ³ãƒ‡ãƒ³ãƒˆã•ã‚ŒãŸãƒ–ãƒãƒƒã‚¯ã§ã¯ã€è¤‡æ•°ã®è¡Œã®ã†ã¡ã€ã‚‚ã£
ã¨ã‚‚æµ…ã„ã‚¤ãƒ³ãƒ‡ãƒ³ãƒˆãŒæ¬²ã—ãã†ã§ã™ã‚ˆãã€‚

ã€€ãŸã¨ãˆã°ã§ã™ãŒã€ RD ã‚„ markdown ã®ã‚ˆã†ãªæ–‡æ›¸ã‚’å‡¦ç†ã™ã‚‹å ´åˆã‚’
è€ƒãˆã¦ã„ã¾ã—ãŸã€‚è€ƒãˆã¦ã¿ã‚‹ã¨ gather ã®å®ˆå‚™ç¯„å›²å¤–ã‹ã‚‚ã—ã‚Œã¾ã›ã‚“ãã€‚

ã‚‚ã—ã€ã©ã†ã—ã¦ã‚‚åˆ†é¡žã®å€¤ãŒå¿…è¦ã ã¨ã„ã†ã“ã¨ã§ã‚ã‚Œã°ã€yield ã™
ã‚‹é…åˆ—ã«ã‚¤ãƒ³ã‚¹ã‚¿ãƒ³ã‚¹å¤‰æ•°ã¨ã—ã¦ã¤ã‘ã¦ãŠã (å¿…è¦ãªã‚‰ãã‚Œã‚’å‚ç…§
ã™ã‚‹ã‚¢ã‚¯ã‚»ã‚µã‚‚) ã®ã«ã¯ã‚„ã¶ã•ã‹ã§ã¯ã‚ã‚Šã¾ã›ã‚“ã€‚

ã€€ãã®å ´åˆã®APIã¯ã©ã†ãªã‚‹ã®ã§ã—ã‚‡ã†ã€‚gather æœ¬æ¥ã®ç”¨é€”ã«ã¯é‚ªé”ãª
ãƒ‡ãƒ¼ã‚¿ãŒãã£ã¤ã„ã¦ã—ã¾ã†ã®ã§ã€åˆ¥ãƒ¡ã‚½ãƒƒãƒ‰ã§ã™ã‹ãã€‚

ã¨ã„ã†ã“ã¨ã§ã‚ã‚Œã°ã€ buffer ã‚’ä½¿ã£ã¦ gather ç‰ã‚’å®Ÿè£…ã™ã‚‹ã®ã¯å®¹æ˜“
ãªã®ã§ã€è¤‡æ•°ã®ãƒ¡ã‚½ãƒƒãƒ‰ã‚’ç”¨æ„ã™ã‚‹ã®ãªã‚‰ã€å®Ÿè£…ã‚’å…±æœ‰ã™ã‚‹ãŸã‚ã«ã‚‚
buffer ã®ã‚ˆã†ãªæ±Žç”¨ã®ã‚‚ã®ã‚’æŒã¤ãƒ¡ãƒªãƒƒãƒˆãŒã‚ã‚‹ã¨ã„ã†ã“ã¨ã«ãªã‚‹ã®
ã§ã¯ãªã„ã§ã—ã‚‡ã†ã‹ã€‚

å®Ÿè£…ã—ã¦ã¿ã¾ã—ãŸãŒã€ãã†ã„ã†ã‚‚ã®ãŒãªãã¦ã‚‚ãã‚Œã»ã©é¢å€’ã§ã¯ã‚
ã‚Šã¾ã›ã‚“ã§ã—ãŸã€‚

ã€€ãªã‚‹ã»ã©ã€‚å®Ÿã¯ map ã® Enumerator ç‰ˆ(é…åˆ—ã‚’ç”Ÿæˆã—ãªã„)ã‚’æ‰‹å…ƒã§
ä½œã£ã¦ã„ãŸã®ã§ã™ãŒã€ Yielder ãŒã‚ã‚Œã°ç°¡å˜ãªã‚“ã§ã™ã‚ˆãã€‚

è¤‡é›‘ãªã“ã¨ãŒã§ãã‚‹ã‹ã‚‰ã„ã‚ã‚“ãªç”¨é€”ãŒã‚ã‚‹ã«é•ã„ãªã„ã€ã¨ã„ã†è©±
ã§ã¯ãªãã€å…·ä½“çš„ãªä¾‹ã¯ã‚ã‚Šã¾ã›ã‚“ã‹?

ã€€ã‚€ã—ã‚ã€ç”°ä¸ã•ã‚“ã®å‡ºã•ã‚ŒãŸ2å•ã‚’å…·ä½“ä¾‹ã¨ã—ãŸã¨ãã®ç§ãªã‚Šã®è§£ãŒ
Buffer ãªã‚“ã§ã™ã‚ˆã€‚scanf.rbã‹ã‚‰ã®ã‚³ãƒ¼ãƒ‰ç‰‡ã®åˆ‡ã‚Šå‡ºã—ã¨ã„ã†æœ€åˆã®
ä¾‹ã¯ã€ã‚³ãƒ¼ãƒ‰ç‰‡ã§ãªã„éƒ¨åˆ†ã‚‚å«ã‚ã¦ pp ã™ã‚‹ã¨ã„ã†ã®ãŒæœ€çµ‚ç›®çš„ã§ã¯
ãªã„ã§ã™ã‚ˆãã€‚å‰Šé™¤ã™ã‚‹ã¨ã„ã†æ©Ÿèƒ½ãŒæ¬ ã‘ã¦ã„ã‚‹ã®ã§ä¸è¦ãªéƒ¨åˆ†ã¾ã§
å¾—ã‚‰ã‚Œã¦ã‚ãšã‚‰ã‚ã—ã„ã€‚å¾“ã£ã¦å–æ¨é¸æŠžã®æ©Ÿèƒ½ãŒå¿…è¦ã§ã¯ãªã„ã‹ã€ã¨
æ€ã„ã¾ã—ãŸã€‚

ã€€æ¬¡ã«ãƒ‘ãƒ©ã‚°ãƒ©ãƒ•ã”ã¨ã«åˆ‡ã‚‹ã¨ã„ã†ä¾‹ã¯ gather_each ãŒã‚‚ã£ã¨ã‚‚çŸã
æ›¸ã‘ã‚‹ä¾‹ã§ã—ãŸã€‚ã—ã‹ã—ãªãŒã‚‰ã€ãƒ˜ãƒƒãƒ€ã‚’åŒºåˆ‡ã‚Šã¨ã™ã‚‹æ§‹é€ ã‚’æ‰±ã†éš›ã¯
çŸããªããªã‚‹ã€‚å¾“ã£ã¦æ£æ„çš„ãªã‚¿ã‚¤ãƒŸãƒ³ã‚°ã§ yield ã§ãã‚‹å¿…è¦ãŒã‚ã‚‹ã€
ã‚ã‚‹ã„ã¯çŠ¶æ…‹ã®ç®¡ç†ã‚’æ”¯æ´ã™ã‚‹ã¨ã„ã„ã®ã§ã¯ãªã„ã‹ã€ã¨æ€ã„ã¾ã—ãŸã€‚

ã€€ã“ã‚Œã‚‰ã‚’åˆã‚ã›ãŸè€ƒãˆãŸã®ãŒ Bufferã§ã™ã€‚å½“ãŸã‚Šå‰ã§ã™ãŒè¤‡é›‘ãªã“ã¨
è‡ªä½“ã‚’ç›®æŒ‡ã—ã¦ã„ã‚‹ã®ã§ã¯ãªãã¦ã€ gather_each ã§ã¯ä¸ååˆ†ã¨æ„Ÿã˜ã€
ä¸€éƒ¨ã®ã‚±ãƒ¼ã‚¹ã‚’é™¤ã‘ã°æœ€é©ãªè§£ã¨ã¯æ€ãˆãªã‹ã£ãŸã®ãŒå¯¾æ¡ˆã®å‹•æ©Ÿã§ã™ã€‚

ã€€ã„ã¡ãŠã†ã€ç§ã‹ã‚‰ã‚‚ã„ãã¤ã‹å…·ä½“ä¾‹ã‚’æŒ™ã’ã¦ã¿ã¾ã™ã€‚ãªãŠã€ç©ºã ã£ãŸã‚‰
yield ã—ãªã„ã¨ã„ã†æ”¹å¤‰ã‚’å‰æã¨ã—ã¦ã„ã¾ã™ã€‚Gist ã«ä¸Šã’ã¾ã—ãŸã€‚

gist.github.com

https://gist.github.com/knu/109550

buffer.rb

class Enumerator
  class Buffer
    attr_accessor :status

    def initialize(yielder, initial_status = nil)
      @buffer = []
      @yielder = yielder
      @status = initial_status
    end

This file has been truncated. show original

Unix mbox ã®åˆ‡ã‚Šåˆ†ã‘:

file.lines.buffer { |line, buf|
buf.flush if /\AFrom / =~ line
buf << line
}

ChangeLog ã®å„ã‚¨ãƒ³ãƒˆãƒªã®åˆ‡ã‚Šå‡ºã—:

open(“ChangeLog”) { |f|
header = nil
f.lines.buffer { |line, buf|
case line
when /\A\S/
# é ãŒç©ºç™½ã§ãªã‘ã‚Œã°ãƒ˜ãƒƒãƒ€
header = line
when /\A\s*\z/
# ç©ºè¡Œã¯åŒºåˆ‡ã‚Š
buf.flush
when /\A\s+*/
# * ã§å§‹ã¾ã‚‹è¡Œã¯ã‚¨ãƒ³ãƒˆãƒªã®å§‹ã¾ã‚Š
buf.flush
if header
buf << header
buf << line
end
when /\A\s+\S/
# ç©ºç™½ã§å§‹ã¾ã‚‹è¡Œã¯ã€ã‚¨ãƒ³ãƒˆãƒªãŒå§‹ã¾ã£ã¦ã„ã‚Œã°ã‚¨ãƒ³ãƒˆãƒªã®ç¶™ç¶šè¡Œ
buf << line unless buf.empty?
end
}.each { |header, *entry_lines|
puts header, *entry_lines
puts ‘----’
}
}

ç°¡å˜ãªé›»å“:

STDIN.lines.buffer { |line, buf|
until line.empty?
line.sub!(/\A\s+/, ‘’)
line.sub!(/\A(\d*.?\d+)/) { buf << [:NUM, $1.to_f]; ‘’ }
line.sub!(/\A([+-/])/) { buf << [:OP, $1.intern]; ‘’ }
end
buf.flush
}.tap { |expr|
result = 0
calc = proc { |x, op, y|
case op
when :+
x + y
when :-
x - y
when :
x * y
when
x / y
end
}
expr.each { |tokens|
op = num = nil
tokens.each { |token|
type, data = token
case type
when :OP
if op && num
result = calc[result, op, num]
end
op = data
when :NUM
num = data
result = num if !op
end
}
if op && num
result = calc[result, op, num]
end
puts “> %g” % result
}
}

Tanaka_A · May 11, 2009, 7:01pm

In article [email protected],
Yukihiro M. [email protected] writes:

|e$B0lEY$KFs$D$N<jB3$-$rEO$9$N$G$O$J$/!“0l$D$N%V%m%C%/$r<u$1<h$je(BEnumeratore$B$rJV$9e(Bgathere$B$H!”=>Mh$Ne(Beache$B$KJ,$1$?J}$,<+A3$K$J$k$N$G$O$J$$$G$7$g$&$+!#e(B

e$B;d$b$=$&;W$$$^$9!#$?$@!"e(BEnumerablee$B$+$i!V>r7o$rK~$?$98B$jO"B3e(B

e$B5$$,$D$$$?$s$G$9$,!"e(Bgather_each e$B$re(B gather e$B$H=>Mh$Ne(B
each e$B$KJ,e(B
e$B$1$k$H!"e(Bgather e$B$r8F$s$G:n$C$?e(B enumerator
e$B$KBP$7$F2?2s$be(B each
e$B$r8F$V$3$H$,$G$-$F$7$^$$$^$9$M!#e(B

e$B>uBV$r07$&$H$3$l$OLdBj$r@8$8$k$+$b$7$l$^$;$s!#e(B

e$B0J2<$Oe(B 3e$B$NG?tHVL$r=|5n$9$k$D$b$j$J%3!<%I$J$N$G$9$,!":G=i$Ne(B
to_a e$B$O0U?^$I$*$j$KF0$-$^$9$,!"e(B2e$B2sL$Ne(B to_a e$B$Oe(B (i
e$B$,e(B 0 e$B$8$ce(B
e$B$J$$$N$Ge(B) e$B7k2L$,0[$J$C$F$$$^$9!#e(B

i = 0
e = %w[a b c d e].gather { i += 1; i % 3 != 0 }
p e.to_a #=> [[“a”, “b”], [“d”, “e”]]
p e.to_a #=> [[“b”, “c”], [“e”]]

gather e$B$G$3$l$rHr$1$k$K$O!“0J2<$N$h$&$K$9$kI,MW$,$”$j$^$9!#e(B

e = Enumerator.new {|y|
i = 0
%w[a b c d e].gather { i += 1; i % 3 != 0 }.each {|a| y << a }
}
p e.to_a #=> [[“a”, “b”], [“d”, “e”]]
p e.to_a #=> [[“a”, “b”], [“d”, “e”]]

e$B$3$NE@$r9M$($k$H!“e(Bbuffer e$B$Ne(B status
e$B$K$O0UL#$,$”$C$?!"$H$$$&e(B
e$B$3$H$+$J$!!#e(B

Tanaka_A · May 11, 2009, 6:44pm

In article [email protected],
Tanaka A. [email protected] writes:

gather e$B$be(B Yielder e$B$r;H$&7A$K$9$l$P!"e(Bgather_each e$B$r$J$/$9$3$He(B
e$B$O2DG=$@$H;W$$$^$9!#e(B

e$B$=$&$$$&7A$G:n$C$F$_$?$N$G$D$1$F$*$-$^$9!#e(B

e$B$U$H;W$$$D$$$?$N$G!“e(Bgather e$B$K$Oe(B chunk_by
e$B$H$$$&L>A0$b$D$1$F$”$j$^$9!#e(B

Enumerable#chunk_by
Enumerable#gather
Enumerable#slice_before

% svn diff --diff-cmd diff -x ‘-u -p’
Index: enum.c

— enum.c (revision 23381)
+++ enum.c (working copy)
@@ -1793,6 +1793,170 @@ enum_cycle(int argc, VALUE argv, VALUE
return Qnil; / not reached */
}

+struct chunk_by_arg {

VALUE categorize;
VALUE prev_value;
VALUE prev_elts;
VALUE yielder;
+};

+static VALUE
+chunk_by_ii(VALUE i, VALUE _argp, int argc, VALUE *argv)
+{

struct chunk_by_arg *argp = (struct chunk_by_arg *)_argp;
VALUE v;
VALUE singleton = ID2SYM(rb_intern(“_singleton”));
VALUE separator = ID2SYM(rb_intern(“_separator”));
ENUM_WANT_SVALUE();
v = rb_funcall(argp->categorize, rb_intern(“call”), 1, i);
if (v == singleton) {
```
   if (!NIL_P(argp->prev_value)) {
```

       rb_funcall(argp->yielder, rb_intern("<<"), 1,

argp->prev_elts);

       argp->prev_value = argp->prev_elts = Qnil;

```
   }
```

   rb_funcall(argp->yielder, rb_intern("<<"), 1, rb_ary_new3(1,

i));

}
else if (!RTEST(v) || v == separator) {
```
   if (!NIL_P(argp->prev_value)) {
```

       rb_funcall(argp->yielder, rb_intern("<<"), 1,

argp->prev_elts);

       argp->prev_value = argp->prev_elts = Qnil;

```
   }
```
}
else if (SYMBOL_P(v) && rb_id2name(SYM2ID(v))[0] == ‘_’) {
rb_raise(rb_eRuntimeError, “symbol begins with an underscore is
reserved”);
}
else {
```
   if (NIL_P(argp->prev_value)) {
```
```
       argp->prev_value = v;
```

       argp->prev_elts = rb_ary_new3(1, i);

```
   }
```
```
   else {
```

       if (rb_equal(argp->prev_value, v)) {

           rb_ary_push(argp->prev_elts, i);

```
       }
```
```
       else {
```

           rb_funcall(argp->yielder, rb_intern("<<"), 1,

argp->prev_elts);

```
           argp->prev_value = v;
```

           argp->prev_elts = rb_ary_new3(1, i);

```
       }
```
```
   }
```
}
return Qnil;
+}

+static VALUE
+chunk_by_i(VALUE yielder, VALUE enumerator, int argc, VALUE *argv)
+{

VALUE enumerable;
struct chunk_by_arg arg;
enumerable = rb_ivar_get(enumerator,
rb_intern(“chunk_by_enumerable”));
arg.categorize = rb_ivar_get(enumerator,
rb_intern(“chunk_by_categorize”));
arg.prev_value = Qnil;
arg.prev_elts = Qnil;
arg.yielder = yielder;
rb_block_call(enumerable, id_each, 0, 0, chunk_by_ii, (VALUE)&arg);
if (!NIL_P(arg.prev_elts))

   rb_funcall(arg.yielder, rb_intern("<<"), 1, arg.prev_elts);

return Qnil;
+}

+/*

- call-seq:

enum.chunk_by {|elt| ... } => enumerator

- Creates an enumerator for iterating chunked elements of enum.
- This method gathers consecutive elements which
- the blocks returns a same value.
- The following values has special meaning:
- - nil, false and :_separator specifies that gathered elements is
    not yielded.
- - :_singleton specifies the element should be gathered only itself.
- Other symbols which begins an underscore may be used in future.
- (1…10).chunk_by {|n| n & 2 }.each {|a| p a }
- #=> [1] # 1 & 2 = 0
- [2, 3] # 2 & 2 = 3 & 2 = 1
- [4, 5] # 4 & 2 = 5 & 2 = 0
- [6, 7] # 6 & 2 = 7 & 2 = 1
- [8, 9] # 8 & 2 = 9 & 2 = 0
- [10] # 10 & 2 = 1
- gather indented blocks.
- io.chunk_by {|line| /\A\s/ =~ line }.each {|lines| pp lines }
*/
+static VALUE
+enum_chunk_by(VALUE enumerable)
+{
VALUE enumerator = rb_obj_alloc(rb_cEnumerator);
rb_ivar_set(enumerator, rb_intern(“chunk_by_enumerable”),
enumerable);
rb_ivar_set(enumerator, rb_intern(“chunk_by_categorize”),
rb_block_proc());
rb_block_call(enumerator, rb_intern(“initialize”), 0, 0,
chunk_by_i, enumerator);
return enumerator;
+}

+struct slice_before_arg {

VALUE separator_p;
VALUE prev_elts;
VALUE yielder;
+};

+static VALUE
+slice_before_ii(VALUE i, VALUE _argp, int argc, VALUE *argv)
+{

struct slice_before_arg *argp = (struct slice_before_arg *)_argp;
ENUM_WANT_SVALUE();
if (RTEST(rb_funcall(argp->separator_p, rb_intern(“call”), 1, i)))
{
```
   if (!NIL_P(argp->prev_elts))
```

       rb_funcall(argp->yielder, rb_intern("<<"), 1,

argp->prev_elts);

   argp->prev_elts = rb_ary_new3(1, i);

}
else {
```
   if (NIL_P(argp->prev_elts))
```

       argp->prev_elts = rb_ary_new3(1, i);

```
   else
```

       rb_ary_push(argp->prev_elts, i);

}
return Qnil;
+}

+static VALUE
+slice_before_i(VALUE yielder, VALUE enumerator, int argc, VALUE *argv)
+{

VALUE enumerable;
struct slice_before_arg arg;
enumerable = rb_ivar_get(enumerator,
rb_intern(“slice_before_enumerable”));
arg.separator_p = rb_ivar_get(enumerator,
rb_intern(“slice_before_separator_p”));
arg.prev_elts = Qnil;
arg.yielder = yielder;
rb_block_call(enumerable, id_each, 0, 0, slice_before_ii,
(VALUE)&arg);
if (!NIL_P(arg.prev_elts))

   rb_funcall(arg.yielder, rb_intern("<<"), 1, arg.prev_elts);

return Qnil;
+}

+static VALUE
+enum_slice_before(VALUE enumerable)
+{

VALUE enumerator = rb_obj_alloc(rb_cEnumerator);
rb_ivar_set(enumerator, rb_intern(“slice_before_enumerable”),
enumerable);
rb_ivar_set(enumerator, rb_intern(“slice_before_separator_p”),
rb_block_proc());
rb_block_call(enumerator, rb_intern(“initialize”), 0, 0,
slice_before_i, enumerator);
return enumerator;
+}

/*

The Enumerable mixin provides collection classes with
several traversal and searching methods, and with the ability to
@@ -1852,6 +2016,9 @@ Init_Enumerable(void)
rb_define_method(rb_mEnumerable, “drop”, enum_drop, 1);
rb_define_method(rb_mEnumerable, “drop_while”, enum_drop_while, 0);
rb_define_method(rb_mEnumerable, “cycle”, enum_cycle, -1);

rb_define_method(rb_mEnumerable, “gather”, enum_chunk_by, 0);
rb_define_method(rb_mEnumerable, “chunk_by”, enum_chunk_by, 0);
rb_define_method(rb_mEnumerable, “slice_before”, enum_slice_before,
0);

id_eqq = rb_intern(“===”);
id_each = rb_intern(“each”);

Tanaka_A · May 12, 2009, 12:58am

e$B@.@%$G$9!#e(B

Tanaka A. wrote:

e$B$r8F$V$3$H$,$G$-$F$7$^$$$^$9$M!#e(B

e$B>uBV$r07$&$H$3$l$OLdBj$r@8$8$k$+$b$7$l$^$;$s!#e(B
…
e$B$3$NE@$r9M$($k$H!“e(Bbuffer e$B$Ne(B status e$B$K$O0UL#$,$”$C$?!"$H$$$&e(B
e$B$3$H$+$J$!!#e(B

Enumerator#each_with_object
e$B$N$h$&$K!“e(Bgather_with_objecte$B$”$?$j$re(B
e$BDs6!$9$l$P$=$l$GB-$j$^$;$s$+$M!#e(B

e$B$"$^$jGI@8%a%=%C%I$,A}$($9$.$k$N$bA1$70-$7$G$O$"$j$^$9$,!#e(B

Tanaka_A · May 12, 2009, 5:14am

In article [email protected],
“NARUSE, Yui” [email protected] writes:

Enumerator#each_with_object e$B$N$h$&$K!“e(Bgather_with_objecte$B$”$?$j$re(B
e$BDs6!$9$l$P$=$l$GB-$j$^$;$s$+$M!#e(B

e$B2r7h$9$k$N$KJL$N%a%=%C%I$K$9$kI,MW$O$J$$$G$7$g$&!#0z?t$rM?$(e(B
e$B$?$i$=$l$,e(B (each e$B$N$?$S$Ke(B dup e$B$5$l$Fe(B)
e$B$^$H$^$j$rH=CG$9$k%V%m%Ce(B
e$B%/$NBhe(B2e$B0z?t$K$o$?$9$H$+!#e(B

e$B$?$H$($P!"e(Bmbox e$B$NJ,3d$G!"6u9T$N8e$Ne(B "From "
e$B$GJ,3d$9$k$J$i!"e(B
e$B0J2<$N$h$&$K$9$k$H$+!#e(B

ARGF.slice_before(emp: true) {|line,h|
prevemp = h[:emp]
h[:emp] = line == “\n”
prevemp && line.start_with?("From ")
}.each {|x| pp x }

e$B$`$7$m;d$,LB$C$F$$$k$N$O$3$l$O2r7h$9$kI,MW$,$“$kLdBj$J$N$+$Ie(B
e$B$&$+!”$H$$$&$H$3$m$G$9!#e(B

e$B8=;~E@$G$O2r7h$7$F$b$$$$$s$8$c$J$$$+$H$$$&5$J,$K79$$$F$$$^$9e(B
e$B$,!#e(B

e$B<BAu$OFq$7$/$J$/$F0J2<$N$h$&$K$G$-$^$9!#e(B

% svn diff --diff-cmd diff -x ‘-u -p’
Index: enum.c

— enum.c (revision 23381)
+++ enum.c (working copy)
@@ -1793,6 +1793,231 @@ enum_cycle(int argc, VALUE argv, VALUE
return Qnil; / not reached */
}

+struct chunk_by_arg {

VALUE categorize;
VALUE state;
VALUE prev_value;
VALUE prev_elts;
VALUE yielder;
+};

+static VALUE
+chunk_by_ii(VALUE i, VALUE _argp, int argc, VALUE *argv)
+{

struct chunk_by_arg *argp = (struct chunk_by_arg *)_argp;
VALUE v;
VALUE singleton = ID2SYM(rb_intern(“_singleton”));
VALUE separator = ID2SYM(rb_intern(“_separator”));
ENUM_WANT_SVALUE();
v = rb_funcall(argp->categorize, rb_intern(“call”), 2, i,
argp->state);
if (v == singleton) {
```
   if (!NIL_P(argp->prev_value)) {
```

       rb_funcall(argp->yielder, rb_intern("<<"), 1,

argp->prev_elts);

       argp->prev_value = argp->prev_elts = Qnil;

```
   }
```

   rb_funcall(argp->yielder, rb_intern("<<"), 1, rb_ary_new3(1,

i));

}
else if (!RTEST(v) || v == separator) {
```
   if (!NIL_P(argp->prev_value)) {
```

       rb_funcall(argp->yielder, rb_intern("<<"), 1,

argp->prev_elts);

       argp->prev_value = argp->prev_elts = Qnil;

```
   }
```
}
else if (SYMBOL_P(v) && rb_id2name(SYM2ID(v))[0] == ‘_’) {
rb_raise(rb_eRuntimeError, “symbol begins with an underscore is
reserved”);
}
else {
```
   if (NIL_P(argp->prev_value)) {
```
```
       argp->prev_value = v;
```

       argp->prev_elts = rb_ary_new3(1, i);

```
   }
```
```
   else {
```

       if (rb_equal(argp->prev_value, v)) {

           rb_ary_push(argp->prev_elts, i);

```
       }
```
```
       else {
```

           rb_funcall(argp->yielder, rb_intern("<<"), 1,

argp->prev_elts);

```
           argp->prev_value = v;
```

           argp->prev_elts = rb_ary_new3(1, i);

```
       }
```
```
   }
```
}
return Qnil;
+}

+static VALUE
+chunk_by_i(VALUE yielder, VALUE enumerator, int argc, VALUE *argv)
+{

VALUE enumerable;
struct chunk_by_arg arg;
enumerable = rb_ivar_get(enumerator,
rb_intern(“chunk_by_enumerable”));
arg.categorize = rb_ivar_get(enumerator,
rb_intern(“chunk_by_categorize”));
arg.state = rb_ivar_get(enumerator,
rb_intern(“chunk_by_initial_state”));
arg.prev_value = Qnil;
arg.prev_elts = Qnil;
arg.yielder = yielder;
if (!NIL_P(arg.state))
```
   arg.state = rb_obj_dup(arg.state);
```
rb_block_call(enumerable, id_each, 0, 0, chunk_by_ii, (VALUE)&arg);
if (!NIL_P(arg.prev_elts))

   rb_funcall(arg.yielder, rb_intern("<<"), 1, arg.prev_elts);

return Qnil;
+}

+/*

- call-seq:

enum.chunk_by(initial_state=nil) {|elt, state| ... } =>

enumerator

- Creates an enumerator for iterating chunked elements of enum.
- This method gathers consecutive elements which
- the block returns a same value.
- The following values has special meaning:
- - nil, false and :_separator specifies that gathered elements is
    not yielded.
- - :_singleton specifies the element should be gathered only itself.
- Other symbols which begins an underscore may be used in future.
- If non-nil value is given for initial_state,
- it is duplicated for each “each” method invocation of the
  enumerator.
- The duplicated object is passed to second argument of the block for
  “chunk_by” method…
- (1…10).chunk_by {|n| n & 2 }.each {|a| p a }
- #=> [1] # 1 & 2 = 0
- [2, 3] # 2 & 2 = 3 & 2 = 1
- [4, 5] # 4 & 2 = 5 & 2 = 0
- [6, 7] # 6 & 2 = 7 & 2 = 1
- [8, 9] # 8 & 2 = 9 & 2 = 0
- [10] # 10 & 2 = 1
- gather indented blocks.
- io.chunk_by {|line| /\A\s/ =~ line }.each {|lines| pp lines }
- iterate over svn log entries.
- IO.popen([{“LANG”=>“C”}, *%w[svn log enum.c]]) {|f|
- ```
 sep = "-"*72+"\n"
```

 f.chunk_by {|line| line != sep }.each {|e| pp e }

- }
*/
+static VALUE
+enum_chunk_by(int argc, VALUE *argv, VALUE enumerable)
+{
VALUE initial_state;
VALUE enumerator;
rb_scan_args(argc, argv, “01”, &initial_state);
enumerator = rb_obj_alloc(rb_cEnumerator);
rb_ivar_set(enumerator, rb_intern(“chunk_by_enumerable”),
enumerable);
rb_ivar_set(enumerator, rb_intern(“chunk_by_categorize”),
rb_block_proc());
rb_ivar_set(enumerator, rb_intern(“chunk_by_initial_state”),
initial_state);
rb_block_call(enumerator, rb_intern(“initialize”), 0, 0,
chunk_by_i, enumerator);
return enumerator;
+}

+struct slice_before_arg {

VALUE separator_p;
VALUE state;
VALUE prev_elts;
VALUE yielder;
+};

+static VALUE
+slice_before_ii(VALUE i, VALUE _argp, int argc, VALUE *argv)
+{

struct slice_before_arg *argp = (struct slice_before_arg *)_argp;
VALUE bool;
ENUM_WANT_SVALUE();
bool = rb_funcall(argp->separator_p, rb_intern(“call”), 2, i,
argp->state);
if (RTEST(bool)) {
```
   if (!NIL_P(argp->prev_elts))
```

       rb_funcall(argp->yielder, rb_intern("<<"), 1,

argp->prev_elts);

   argp->prev_elts = rb_ary_new3(1, i);

}
else {
```
   if (NIL_P(argp->prev_elts))
```

       argp->prev_elts = rb_ary_new3(1, i);

```
   else
```

       rb_ary_push(argp->prev_elts, i);

}
return Qnil;
+}

+static VALUE
+slice_before_i(VALUE yielder, VALUE enumerator, int argc, VALUE *argv)
+{

VALUE enumerable;
struct slice_before_arg arg;
enumerable = rb_ivar_get(enumerator,
rb_intern(“slice_before_enumerable”));
arg.separator_p = rb_ivar_get(enumerator,
rb_intern(“slice_before_separator_p”));
arg.state = rb_ivar_get(enumerator,
rb_intern(“slice_before_initial_state”));
arg.prev_elts = Qnil;
arg.yielder = yielder;
if (!NIL_P(arg.state))
```
   arg.state = rb_obj_dup(arg.state);
```
rb_block_call(enumerable, id_each, 0, 0, slice_before_ii,
(VALUE)&arg);
if (!NIL_P(arg.prev_elts))

   rb_funcall(arg.yielder, rb_intern("<<"), 1, arg.prev_elts);

return Qnil;
+}

+/*

- call-seq:

enum.slice_before(initial_state=nil) {|elt, state| ... } =>

enumerator

- Creates an enumerator for iterating gathered elements of enum.
- This method gathers consecutive elements which
- the block returns a true for the starting element.
- If non-nil value is given for initial_state,
- it is duplicated for each “each” method invocation of the
  enumerator.
- The duplicated object is passed to second argument of the block for
  “chunk_by” method…
- iterate over ChangeLog entries.
- open(“ChangeLog”) {|f|

 f.slice_before {|line| /\A\S/ =~ line }.each {|e| pp e}

- }
- split mails in mbox (slice before Unix From line after an empty

line)

- open(“mbox”) {|f|
- ```
 f.slice_before(emp: true) {|line,h|
```
- ```
 prevemp = h[:emp]
```
- ```
 h[:emp] = line == "\n"
```
- ```
 prevemp && line.start_with?("From ")
```
- }.each {|mail|
- ```
 pp mail
```
- }
*/
+static VALUE
+enum_slice_before(int argc, VALUE *argv, VALUE enumerable)
+{
VALUE initial_state, enumerator;
rb_scan_args(argc, argv, “01”, &initial_state);
enumerator = rb_obj_alloc(rb_cEnumerator);
rb_ivar_set(enumerator, rb_intern(“slice_before_enumerable”),
enumerable);
rb_ivar_set(enumerator, rb_intern(“slice_before_separator_p”),
rb_block_proc());
rb_ivar_set(enumerator, rb_intern(“slice_before_initial_state”),
initial_state);
rb_block_call(enumerator, rb_intern(“initialize”), 0, 0,
slice_before_i, enumerator);
return enumerator;
+}

/*

The Enumerable mixin provides collection classes with
several traversal and searching methods, and with the ability to
@@ -1852,6 +2077,9 @@ Init_Enumerable(void)
rb_define_method(rb_mEnumerable, “drop”, enum_drop, 1);
rb_define_method(rb_mEnumerable, “drop_while”, enum_drop_while, 0);
rb_define_method(rb_mEnumerable, “cycle”, enum_cycle, -1);

rb_define_method(rb_mEnumerable, “gather”, enum_chunk_by, -1);
rb_define_method(rb_mEnumerable, “chunk_by”, enum_chunk_by, -1);
rb_define_method(rb_mEnumerable, “slice_before”, enum_slice_before,
-1);

id_eqq = rb_intern(“===”);
id_each = rb_intern(“each”);

Tanaka_A · May 14, 2009, 4:35pm

In article [email protected],
Tanaka A. [email protected] writes:

Python e$B$N$h$&$K!"e(Beach e$B$N%V%m%C%/$NBh0l0z?t$KEO$7$F$b$$$$$N$+e(B
e$B$b$7$l$^$;$s!#e(B

enum.gather(init_state) {|elt,state| … }.each {|category,ary| … }

e$B$3$&$9$k$H!"$3$l$,e(B group_by e$B$H;w$F$$$k$3$H$,$h$/$o$+$j$^$9!#e(B

% ./ruby -e ‘(1…10).gather {|e| e & 4 }.each {|x| p x }’
[0, [1, 2, 3]]
[4, [4, 5, 6, 7]]
[0, [8, 9, 10]]
% ./ruby -e ‘(1…10).group_by {|e| e & 4 }.each {|x| p x }’
[0, [1, 2, 3, 8, 9, 10]]
[4, [4, 5, 6, 7]]

gather e$B$Oe(B 1, 2, 3 e$B$He(B 8, 9, 10 e$B$,$o$+$l$F$$$^$9$,!"e(B
group_by e$B$O:G8e$^$G$_$k$N$G$=$l$i$,$^$H$^$C$F$$$^$9!#e(B

e$B$^$!!"JV$jCM$,e(B Enumerator e$B$He(B Hash
e$B$H0c$C$?$j$b$9$k$N$G!"A4BNe(B
e$B$H$7$F;w$F$$$k$+$H$$$&$H$^$?JL$G$9$,!#e(B

e$B$H$$$&$h$&$K<BAu$7$F$_$?$b$N$r$D$1$F$*$-$^$9!#e(B

% svn diff --diff-cmd diff -x ‘-u -p’
Index: enum.c

— enum.c (revision 23381)
+++ enum.c (working copy)
@@ -1793,6 +1793,247 @@ enum_cycle(int argc, VALUE argv, VALUE
return Qnil; / not reached */
}

+struct chunk_by_arg {

VALUE categorize;
VALUE state;
VALUE prev_value;
VALUE prev_elts;
VALUE yielder;
+};

+static VALUE
+chunk_by_ii(VALUE i, VALUE _argp, int argc, VALUE *argv)
+{

struct chunk_by_arg *argp = (struct chunk_by_arg *)_argp;
VALUE v;
VALUE singleton = ID2SYM(rb_intern(“_singleton”));
VALUE separator = ID2SYM(rb_intern(“_separator”));
ENUM_WANT_SVALUE();
v = rb_funcall(argp->categorize, rb_intern(“call”), 2, i,
argp->state);
if (v == singleton) {
```
   if (!NIL_P(argp->prev_value)) {
```

       rb_funcall(argp->yielder, rb_intern("<<"), 1,

rb_assoc_new(argp->prev_value, argp->prev_elts));

       argp->prev_value = argp->prev_elts = Qnil;

```
   }
```

   rb_funcall(argp->yielder, rb_intern("<<"), 1, rb_assoc_new(v,

rb_ary_new3(1, i)));

}
else if (!RTEST(v) || v == separator) {
```
   if (!NIL_P(argp->prev_value)) {
```

       rb_funcall(argp->yielder, rb_intern("<<"), 1,

rb_assoc_new(argp->prev_value, argp->prev_elts));

       argp->prev_value = argp->prev_elts = Qnil;

```
   }
```
}
else if (SYMBOL_P(v) && rb_id2name(SYM2ID(v))[0] == ‘_’) {
rb_raise(rb_eRuntimeError, “symbol begins with an underscore is
reserved”);
}
else {
```
   if (NIL_P(argp->prev_value)) {
```
```
       argp->prev_value = v;
```

       argp->prev_elts = rb_ary_new3(1, i);

```
   }
```
```
   else {
```

       if (rb_equal(argp->prev_value, v)) {

           rb_ary_push(argp->prev_elts, i);

```
       }
```
```
       else {
```

           rb_funcall(argp->yielder, rb_intern("<<"), 1,

rb_assoc_new(argp->prev_value, argp->prev_elts));

```
           argp->prev_value = v;
```

           argp->prev_elts = rb_ary_new3(1, i);

```
       }
```
```
   }
```
}
return Qnil;
+}

+static VALUE
+chunk_by_i(VALUE yielder, VALUE enumerator, int argc, VALUE *argv)
+{

VALUE enumerable;
struct chunk_by_arg arg;
enumerable = rb_ivar_get(enumerator,
rb_intern(“chunk_by_enumerable”));
arg.categorize = rb_ivar_get(enumerator,
rb_intern(“chunk_by_categorize”));
arg.state = rb_ivar_get(enumerator,
rb_intern(“chunk_by_initial_state”));
arg.prev_value = Qnil;
arg.prev_elts = Qnil;
arg.yielder = yielder;
if (!NIL_P(arg.state))
```
   arg.state = rb_obj_dup(arg.state);
```
rb_block_call(enumerable, id_each, 0, 0, chunk_by_ii, (VALUE)&arg);
if (!NIL_P(arg.prev_elts))

   rb_funcall(arg.yielder, rb_intern("<<"), 1,

rb_assoc_new(arg.prev_value, arg.prev_elts));

return Qnil;
+}

+/*

- call-seq:

enum.chunk_by(initial_state=nil) {|elt, state| ... } =>

enumerator

- Creates an enumerator for iterating chunked elements of enum.
- This method gathers consecutive elements which
- the block returns a same value.
- The following values has special meaning:
- - nil, false and :_separator specifies that gathered elements is
    not yielded.
- - :_singleton specifies the element should be gathered only itself.
- Other symbols which begins an underscore may be used in future.
- If non-nil value is given for initial_state,
- it is duplicated for each “each” method invocation of the
  enumerator.
- The duplicated object is passed to second argument of the block for
  “chunk_by” method…
- (1…10).chunk_by {|n| n & 2 }.each {|a| p a }
- #=> [1] # 1 & 2 = 0
- [2, 3] # 2 & 2 = 3 & 2 = 1
- [4, 5] # 4 & 2 = 5 & 2 = 0
- [6, 7] # 6 & 2 = 7 & 2 = 1
- [8, 9] # 8 & 2 = 9 & 2 = 0
- [10] # 10 & 2 = 1
- gather indented blocks.
- io.chunk_by {|line| /\A\s/ =~ line }.each {|lines| pp lines }
- iterate over svn log entries.
- IO.popen([{“LANG”=>“C”}, *%w[svn log enum.c]]) {|f|
- ```
 sep = "-"*72+"\n"
```

 f.chunk_by {|line| line != sep }.each {|e| pp e }

- }
*/
+static VALUE
+enum_chunk_by(int argc, VALUE *argv, VALUE enumerable)
+{
VALUE initial_state;
VALUE enumerator;
rb_scan_args(argc, argv, “01”, &initial_state);
enumerator = rb_obj_alloc(rb_cEnumerator);
rb_ivar_set(enumerator, rb_intern(“chunk_by_enumerable”),
enumerable);
rb_ivar_set(enumerator, rb_intern(“chunk_by_categorize”),
rb_block_proc());
rb_ivar_set(enumerator, rb_intern(“chunk_by_initial_state”),
initial_state);
rb_block_call(enumerator, rb_intern(“initialize”), 0, 0,
chunk_by_i, enumerator);
return enumerator;
+}

+struct slice_before_arg {

VALUE separator_p;
VALUE state;
VALUE prev_elts;
VALUE yielder;
+};

+static VALUE
+slice_before_ii(VALUE i, VALUE _argp, int argc, VALUE *argv)
+{

struct slice_before_arg *argp = (struct slice_before_arg *)_argp;
VALUE bool;
ENUM_WANT_SVALUE();
bool = rb_funcall(argp->separator_p, rb_intern(“call”), 2, i,
argp->state);
if (RTEST(bool)) {
```
   if (!NIL_P(argp->prev_elts))
```

       rb_funcall(argp->yielder, rb_intern("<<"), 1,

argp->prev_elts);

   argp->prev_elts = rb_ary_new3(1, i);

}
else {
```
   if (NIL_P(argp->prev_elts))
```

       argp->prev_elts = rb_ary_new3(1, i);

```
   else
```

       rb_ary_push(argp->prev_elts, i);

}
return Qnil;
+}

+static VALUE
+slice_before_i(VALUE yielder, VALUE enumerator, int argc, VALUE *argv)
+{

VALUE enumerable;
struct slice_before_arg arg;
enumerable = rb_ivar_get(enumerator,
rb_intern(“slice_before_enumerable”));
arg.separator_p = rb_ivar_get(enumerator,
rb_intern(“slice_before_separator_p”));
arg.state = rb_ivar_get(enumerator,
rb_intern(“slice_before_initial_state”));
arg.prev_elts = Qnil;
arg.yielder = yielder;
if (!NIL_P(arg.state))
```
   arg.state = rb_obj_dup(arg.state);
```
rb_block_call(enumerable, id_each, 0, 0, slice_before_ii,
(VALUE)&arg);
if (!NIL_P(arg.prev_elts))

   rb_funcall(arg.yielder, rb_intern("<<"), 1, arg.prev_elts);

return Qnil;
+}

+/*

- call-seq:

enum.slice_before(initial_state=nil) {|elt, state| ... } =>

enumerator

- Creates an enumerator for iterating gathered elements of enum.
- This method gathers consecutive elements which
- the block returns a true for the starting element.
- If non-nil value is given for initial_state,
- it is duplicated for each “each” method invocation of the
  enumerator.
- The duplicated object is passed to second argument of the block for
  “chunk_by” method…
- iterate over ChangeLog entries.
- open(“ChangeLog”) {|f|

 f.slice_before {|line| /\A\S/ =~ line }.each {|e| pp e}

- }
- parse mbox
- open(“mbox”) {|f|
- ```
 f.slice_before {|line|
```
- ```
   line.start_with? "From "
```
- ```
 }.each {|mail|
```
- ```
   unix_from = mail.shift
```
- ```
   i = mail.index("\n")
```
- ```
   header = mail[0...i]
```
- ```
   body = mail[(i+1)..-1]
```

   fields = header.slice_before {|line| !" \t".include?(line[0])

}.to_a

- ```
   p unix_from
```
- ```
   pp fields
```
- ```
   pp body
```
- ```
 }
```
- }
- split mails in mbox (slice before Unix From line after an empty

line)

- open(“mbox”) {|f|
- ```
 f.slice_before(emp: true) {|line,h|
```
- ```
 prevemp = h[:emp]
```
- ```
 h[:emp] = line == "\n"
```
- ```
 prevemp && line.start_with?("From ")
```
- }.each {|mail|
- ```
 pp mail
```
- }
*/
+static VALUE
+enum_slice_before(int argc, VALUE *argv, VALUE enumerable)
+{
VALUE initial_state, enumerator;
rb_scan_args(argc, argv, “01”, &initial_state);
enumerator = rb_obj_alloc(rb_cEnumerator);
rb_ivar_set(enumerator, rb_intern(“slice_before_enumerable”),
enumerable);
rb_ivar_set(enumerator, rb_intern(“slice_before_separator_p”),
rb_block_proc());
rb_ivar_set(enumerator, rb_intern(“slice_before_initial_state”),
initial_state);
rb_block_call(enumerator, rb_intern(“initialize”), 0, 0,
slice_before_i, enumerator);
return enumerator;
+}

/*

The Enumerable mixin provides collection classes with
several traversal and searching methods, and with the ability to
@@ -1852,6 +2093,9 @@ Init_Enumerable(void)
rb_define_method(rb_mEnumerable, “drop”, enum_drop, 1);
rb_define_method(rb_mEnumerable, “drop_while”, enum_drop_while, 0);
rb_define_method(rb_mEnumerable, “cycle”, enum_cycle, -1);

rb_define_method(rb_mEnumerable, “gather”, enum_chunk_by, -1);
rb_define_method(rb_mEnumerable, “chunk_by”, enum_chunk_by, -1);
rb_define_method(rb_mEnumerable, “slice_before”, enum_slice_before,
-1);

id_eqq = rb_intern(“===”);
id_each = rb_intern(“each”);

Tanaka_A · May 14, 2009, 4:41pm

In article [email protected],
Yukihiro M. [email protected] writes:

e$B;d$b$=$&;W$$$^$9!#$?$@!"e(BEnumerablee$B$+$i!V>r7o$rK~$?$98B$jO"B3e(B
e$B$7$?MWAG$r$^$H$a$k!W$3$H$re(Bgathere$B$H8F$V$3$H$K$J$s$H$J$/K~B-$Ge(B
e$B$-$^$;$s!#e(Bgathere$B$H$$$&C18l$+$i$OA4BN$+$i=8$a$k$h$&$J0u>]$r<ue(B
e$B$1$^$;$s$+!)e(B e$B;d$@$1$N463P$G$7$g$&$+!#e(B

gather e$B$O!V!RJ*$r!S0l$D0l$D=&$&!W$H$$$C$?0UL#$,$“$k$N$G!”$=e(B
e$B$N7|G0$O@5$7$$$+$b$7$l$^$;$s!#7k2L$N$^$H$^$j$,!"$b$H$b$H$^$He(B
e$B$^$C$F$$$?$H$O8B$i$J$$$N$O$=$&$J$N$G$7$g$&!#e(B

e$B$G!"$7$P$i$/9M$($?$N$G$9$,!“e(Bchunk e$B$J$$$7e(B chunk_by
e$B$O$I$&$G$7$ge(B
e$B$&$+!#$3$C$A$O!V!J%Q%s!&Fy!&@PC:$J$I$N!KBg$-$$$+$?$^$je(B, e$B$V$De(B
e$B@Z$je(B,e$B8|@Z$j!W$J$N$G!”@Z$j=P$7$?$b$N$O$b$H$b$H$/$C$D$$$F$$$?e(B
e$B0UL#$,$H$l$k$h$&$K;W$$$^$9!#e(B

Tanaka_A · May 14, 2009, 6:13pm

e$B1sF#$G$9!#e(B

gather e$B$O4pK\E*$K;?@.$J$s$G$9$,!“e(Bnil e$B$NFCJL07$$$,$A$g$C$He(B
e$B5$;}$A0-$$$G$9!#%”%I%[%C%/$H$$$&$+!“%7%s%W%k$JL>A0$KH?$7$Fe(B
e$B5!G=$,5M$a9~$^$l$9$.$F$$$k!”$H$$$&0u>]$G$9!#e(B

e$B$=$&$$$&E@$G!"e(B

2009/05/14 11:14 Tanaka A. [email protected]:

Python e$B$N$h$&$K!"e(Beach e$B$N%V%m%C%/$NBh0l0z?t$KEO$7$F$b$$$$$N$+e(B
e$B$b$7$l$^$;$s!#e(B

enum.gather(init_state) {|elt,state| … }.each {|category,ary| … }

e$B$3$N%$%s%?!<%U%'%$%9$O$H$F$b$$$$$H;W$$$^$9!#e(B

enum.gather {|elt| … }.select {|cat, ary| cat }

e$B$H<+A3$KJ,N%$G$-$^$9!#e(B
e$B<N$F$kItJ,$^$Ge(B ary e$B$r:n$k$N$,B?>/5$$K$J$k$+$b$7$l$^$;$s$,!"e(B
nil e$B$NFCJL07$$$^$G$9$k%a%=%C%I$Oe(B gather e$B$h$jD9$/$FL@3N$Je(B
e$B%a%=%C%IL>$GJL$KMQ0U$7$?J}$,$$$$$H;W$$$^$7$?!#e(B

e$B$^$H$^$j$+$1$N5DO@$r0z$CA_$-2s$9$h$&$G?=$7Lu$"$j$^$;$s$,!"e(B
e$B0l1~0U8+$G$7$?!#e(B

e$B$J$*!“e(BEnumerable#group_by e$B$O$9$G$K$”$k$N$G!"L>A0$K$D$$$F??;we(B
e$B$G$-$J$$$N$O;DG0$J$H$3$m$G$9!#e(B

e$B$H$F$b;DG0$G$9!#e(B
e$B$G$be(B chunk e$B$Oe(B (e$BHs%M%$%F%#%VE*$K$Oe(B)
e$B$h$5$2$KJ9$3$($^$7$?!#e(B

Tanaka_A · May 15, 2009, 5:53am

e$B$^$D$b$He(B e$B$f$-$R$m$G$9e(B

In message “Re: [ruby-dev:38450] Re: Enumerable#gather_each”
on Thu, 14 May 2009 23:40:41 +0900, Tanaka A. [email protected]
writes:

|e$B$G!"$7$P$i$/9M$($?$N$G$9$,!“e(Bchunk e$B$J$$$7e(B chunk_by e$B$O$I$&$G$7$ge(B
|e$B$&$+!#$3$C$A$O!V!J%Q%s!&Fy!&@PC:$J$I$N!KBg$-$$$+$?$^$je(B, e$B$V$De(B
|e$B@Z$je(B,e$B8|@Z$j!W$J$N$G!”@Z$j=P$7$?$b$N$O$b$H$b$H$/$C$D$$$F$$$?e(B
|e$B0UL#$,$H$l$k$h$&$K;W$$$^$9!#e(B

chunke$B$K$O$3$N0UL#$GF0;l$K$J$i$J$$$N$,5$$K$J$j$^$9!#e(B
e$B$9$G$K=P$F$$$?e(Bslice_bye$B$H$+$,$$$$$h$&$J5$$b$7$^$9!#e(B

e$B$,!"EDCf$5$s$,Ds0F$7$F$$$k5!G=A4Ite(B(e$BMWAG:o=|$H$+e(B)e$B$Oe(Bslice_bye$B$Ge(B
e$B$OI=8=$7$-$l$J$$$h$&$J5$$b$7$^$9$,!#e(B

Tanaka_A · May 14, 2009, 4:15am

Haskell e$B$Ne(B groupBy e$B$He(B Python e$B$Ne(B groupby
e$B$,;w$F$$$k!"$H$$$&OCe(B
e$B$r65$($F$b$i$C$?$N$G!"D4$Y$F;W$C$?$s$G$9$,!"e(B

In article [email protected],
Tanaka A. [email protected] writes:

ary.category e$B$H$+$G$$$$$s$8$c$J$$$G$7$g$&$+!#G[Ns$K%a%=%C%Ie(B
e$B$,$"$C$?$+$i$C$F<YKb$K$O$J$j$^$;$s$h$M!#e(B

enum.gather { … }.each {|ary| p ary.category }

Python e$B$N$h$&$K!"e(Beach e$B$N%V%m%C%/$NBh0l0z?t$KEO$7$F$b$$$$$N$+e(B
e$B$b$7$l$^$;$s!#e(B

enum.gather(init_state) {|elt,state| … }.each {|category,ary| … }

e$B$J$*!“e(BEnumerable#group_by e$B$O$9$G$K$”$k$N$G!"L>A0$K$D$$$F??;we(B
e$B$G$-$J$$$N$O;DG0$J$H$3$m$G$9!#e(B

Tanaka_A · May 15, 2009, 6:25am

In article [email protected],
Yukihiro M. [email protected] writes:

chunke$B$K$O$3$N0UL#$GF0;l$K$J$i$J$$$N$,5$$K$J$j$^$9!#e(B
e$B$9$G$K=P$F$$$?e(Bslice_bye$B$H$+$,$$$$$h$&$J5$$b$7$^$9!#e(B

slice_by e$B$,5$$KF~$i$J$$$H$$$&$o$1$G$O$"$j$^$;$s$,!"e(B

e$B$Ge(B chunk e$B$r$R$/$He(B

verb (used with object)

 to cut, break, or form into chunks: Chunk that wedge of cheese

and put the pieces on a plate.

e$B$H$“$k$N$G!”$=$N0UL#$G$NF0;l$b$“$k$H$$$&8+J}$b$”$k$h$&$G$9!#e(B

e$B$,!"EDCf$5$s$,Ds0F$7$F$$$k5!G=A4Ite(B(e$BMWAG:o=|$H$+e(B)e$B$Oe(Bslice_bye$B$Ge(B
e$B$OI=8=$7$-$l$J$$$h$&$J5$$b$7$^$9$,!#e(B

e$B>e5-$NB3$-$G!"e(B

 to remove a chunk or chunks from (often fol. by out): Storms

have chunked out the road.

e$B$H$$$&$h$&$K!"=|5n$9$k$H$$$&0UL#$K$b;H$($k$h$&$G$9!#e(B

e$B$J$*!“e(Bslice_by e$B$O!“e(Bslice_after
e$B$H$N4X78$,5$$K$J$j$^$9!#e(B
e$B$`$7$m;w$F$$$k$+$iF1$88l$r;H$&!”$H$$$&$N$b$”$jF@$^$9$,!#e(B

Tanaka_A · May 15, 2009, 7:07am

In article
[email protected],
Yusuke ENDOH [email protected] writes:

enum.gather {|elt| … }.select {|cat, ary| cat }

e$B$H<+A3$KJ,N%$G$-$^$9!#e(B
e$B<N$F$kItJ,$^$Ge(B ary e$B$r:n$k$N$,B?>/5$$K$J$k$+$b$7$l$^$;$s$,!"e(B

e$B$b$H$b$HBP>]$,Bg$-$$$H$-$rBP>]$K9M$($F$$$k$N$G!"6=L#$N$J$$Ite(B
e$BJ,$O$J$k$Y$/4JC1$K=hCV$7$?$$$J$!$H;W$C$F$$$^$9!#e(B

e$B$?$H$($P!“e(Bchkbuild e$B$N%m%0$Ge(B minitest
e$B$,%F%9%H$N=gHV$r%i%s%@e(B
e$B%`$KJQ$($k$H$3$m$O%=!<%H$7$F$+$ie(B diff e$B$7$?$$$s$G$9$,!“e(B
http://www.rubyist.net/~akr/chkbuild/debian/ruby-trunk/log/20081213T111000.txt.gz
e$B$N$h$&$K!”%F%9%H0J30$N$H$3$m$,Hs>o$KBg$-$$$3$H$b$”$C$F!“$=$&e(B
e$B$$$&$H$3$m$O4JC1$Ke(B 1e$B9T$:$D=PNO$7$F$$$-$?$$!”$H$$$&%1!<%9$,$"e(B
e$B$j$^$9!#e(B

e$B$=$N$?$a$Ke(B :_singleton e$B$,$“$k$s$G$9$,!”$3$l$,$J$$$He(B

enum.gather {|line| condition ? value : :_singleton }

e$B$H$$$&$N$,e(B

enum.gather(n: 0) {|line| condition ? value : (h[:n] += 1) }

e$B$J$I$H$J$C$F!">uBV$rF3F~$7$J$$$H$$$1$J$$$3$H$K$J$j$^$9!#e(B

e$B$"$kMWAG$rC1FH$G$^$H$^$j$H$9$k$H$$$&H=CG$OMWAGKh$K$G$-$F!“MWe(B
e$BAG4V$N4X78$O$J$$$N$K!”>uBV$r07$o$J$$$H$$$1$J$$$N$O7y$@$J$!!"e(B
e$B$H!#e(B

nil e$B$NFCJL07$$$^$G$9$k%a%=%C%I$Oe(B gather e$B$h$jD9$/$FL@3N$Je(B
e$B%a%=%C%IL>$GJL$KMQ0U$7$?J}$,$$$$$H;W$$$^$7$?!#e(B

e$BFCJL07$$$JCM$rL\N)$?$J$$$H$3$m$K;}$C$F$$$/$3$H$O2DG=$@$H;W$$e(B
e$B$^$9!#e(B

[ruby-dev:38449] e$B$H$+%Q%C%A$NCf$Ne(B rdoc e$B$K$O=q$$$F$"$k$s$G$9e(B
e$B$,!"8=:_!"e(B
nil, false, :_separator e$B$,:o=|$G!"e(B
:_singleton e$B$,C1FH$G$N$^$H$^$j$N;XDj$G$9!#e(B

nil, false e$B$OL\N)$D$N$G!"%7%s%%k$@$1$H$$$&$N$O$R$H$D$N0F$+e(B
e$B$b$7$l$^$;$s!#e(B

e$B$?$@!“e(B[ruby-dev:38394] e$B$N$h$&$J4|BT$KEz$($k$J$i!”$`$7$me(B nil,
false e$B$r:o=|$H$9$k$N$O@5$7$$$N$+$b$7$l$J$$!"$H$b;W$$$^$9!#e(B

Tanaka_A · May 15, 2009, 1:33pm

e$B1sF#$G$9!#e(B

2009/05/15 14:06 Tanaka A. [email protected]:

e$B$?$H$($P!“e(Bchkbuild e$B$N%m%0$Ge(B minitest e$B$,%F%9%H$N=gHV$r%i%s%@e(B
e$B%`$KJQ$($k$H$3$m$O%=!<%H$7$F$+$ie(B diff e$B$7$?$$$s$G$9$,!“e(B
http://www.rubyist.net/~akr/chkbuild/debian/ruby-trunk/log/20081213T111000.txt.gz
e$B$N$h$&$K!”%F%9%H0J30$N$H$3$m$,Hs>o$KBg$-$$$3$H$b$”$C$F!“$=$&e(B
e$B$$$&$H$3$m$O4JC1$Ke(B 1e$B9T$:$D=PNO$7$F$$$-$?$$!”$H$$$&%1!<%9$,$"e(B
e$B$j$^$9!#e(B

e$B$=$&$$$&%1!<%9$O$h$/$“$k$b$N$J$s$G$7$g$&$+!#e(B
nil e$B$NJ}$O5$L#$,0-$$$b$N$N<{MW$O$”$j$=$&$@$H;W$&$s$G$9$,!“e(B
:_singleton e$B$O$b$C$HIT5$L#$G!”$K$b4X$o$i$:;H$$$I$3$m$,e(B
e$B$"$^$j;W$$$D$-$^$;$s!#e(B

e$B>uBV$r;}$?$;$k$H8@$C$F$b!"$R$I$/J#;($K$O$J$C$F$$$^$;$s$7!“e(B
e$B$=$l$[$IH/@8$7$J$$%1!<%9$J$i$=$N$/$i$$$7$F$b$i$C$F$b$$$$e(B
e$B$+$J!”$H;W$$$^$7$?!#e(B
e$B8DJL$N@Z$jJ,$1J}$KBP1~$7;O$a$?$i%-%j$,$J$$$H$$$&$+!#e(B

e$B$G$9$,!"e(B

[ruby-dev:38449] e$B$H$+%Q%C%A$NCf$Ne(B rdoc e$B$K$O=q$$$F$"$k$s$G$9e(B
e$B$,!"8=:_!"e(B
nil, false, :_separator e$B$,:o=|$G!"e(B
:_singleton e$B$,C1FH$G$N$^$H$^$j$N;XDj$G$9!#e(B

_ e$B$G;O$^$k%7%s%%k$J$i!"$$$+$K$bFC<l$J0UL#$r;}$C$F$$$=$&$Je(B
e$B%*!<%i$,=P$F$k$N$G!"5v$;$k5$$b$7$F$-$^$7$?!#e(B
e$B$$$$2C8:$G$9$_$^$;$s!#e(B

nil, false e$B$OL\N)$D$N$G!"%7%s%%k$@$1$H$$$&$N$O$R$H$D$N0F$+e(B
e$B$b$7$l$^$;$s!#e(B

e$B$?$@!“e(B[ruby-dev:38394] e$B$N$h$&$J4|BT$KEz$($k$J$i!”$`$7$me(B nil,
false e$B$r:o=|$H$9$k$N$O@5$7$$$N$+$b$7$l$J$$!"$H$b;W$$$^$9!#e(B

e$B$=$&$G$9$M!#:o=|$H$$$&0UL#$G$J$/J,N`$N0UL#$Ge(B nil e$B$de(B false
e$B$r;H$&$3$H$O$[$H$s$I$J$5$=$&$G$9$7!#e(B

nil e$B$NFCJL07$$$O$I$&$9$k$K$7$F$b!"e(BPython e$B$Ne(B API
e$B$N$h$&$K!“e(B
e$B%+%F%4%j$r$”$o$;$Fe(B yield e$B$9$k$H$3$m$O??;w$7$FM_$7$$$G$9!#e(B
e$B$G$J$$$H!"e(Bgather e$B8e$K%+%F%4%j$r:F7W;;$9$k%3!<%I$,NL;:$5$le(B
e$B$=$&$G$9!#$3$s$JIw$K!"e(Bcategory e$B$rFs2s8F$S$?$/$J$$$G$9!#e(B

enum.gather {|x| category(x) }.each do |ary|
case category(ary.first)
…
end
end

Tanaka_A · May 15, 2009, 3:23pm

e$B@.@%$G$9!#e(B

Yusuke ENDOH wrote:

nil, false e$B$OL\N)$D$N$G!"%7%s%%k$@$1$H$$$&$N$O$R$H$D$N0F$+e(B
e$B$b$7$l$^$;$s!#e(B

e$B$?$@!“e(B[ruby-dev:38394] e$B$N$h$&$J4|BT$KEz$($k$J$i!”$`$7$me(B nil,
false e$B$r:o=|$H$9$k$N$O@5$7$$$N$+$b$7$l$J$$!"$H$b;W$$$^$9!#e(B

e$B$=$&$G$9$M!#:o=|$H$$$&0UL#$G$J$/J,N`$N0UL#$Ge(B nil e$B$de(B false
e$B$r;H$&$3$H$O$[$H$s$I$J$5$=$&$G$9$7!#e(B

nile$B$He(Bfalsee$BN>J}$G$J$/!“JRJ}$K$7$?J}$,$$$$$N$G$O$J$$$G$9$+$M!#e(B
true/falsee$B$J%a%=%C%I$NLa$jCM$GJ,N`$H$$$&$N$O$=$l$J$j$K$”$k$H;W$&$N$G$9$,!#e(B

Tanaka_A · May 17, 2009, 2:22pm

In article [email protected],
“NARUSE, Yui” [email protected] writes:

nile$B$He(Bfalsee$BN>J}$G$J$/!“JRJ}$K$7$?J}$,$$$$$N$G$O$J$$$G$9$+$M!#e(B
true/falsee$B$J%a%=%C%I$NLa$jCM$GJ,N`$H$$$&$N$O$=$l$J$j$K$”$k$H;W$&$N$G$9$,!#e(B

e$B:#$O!"e(Bnil e$B$He(B false
e$B$r;H$$J,$1$k$N$OLLE]$J$s$8$c$J$$$+$J$!!“e(B
e$B$H;W$C$FF1$807$$$K$7$F$”$j$^$9!#e(B

e$B;H$&$H$-$K!"$I$C$A$,$I$C$A$@$C$?$+;W$$=P$;$J$+$C$?$j$7$^$;$se(B
e$B$+$M!#e(B

e$B$J$*!"$b$7$b$I$A$i$+JRJ}$K$9$k$J$i!"e(Bnil e$B$@$H$O;W$$$^$9!#e(B

Tanaka_A · May 17, 2009, 2:20pm

In article
[email protected],
Yusuke ENDOH [email protected] writes:

e$B$=$&$$$&%1!<%9$O$h$/$“$k$b$N$J$s$G$7$g$&$+!#e(B
nil e$B$NJ}$O5$L#$,0-$$$b$N$N<{MW$O$”$j$=$&$@$H;W$&$s$G$9$,!“e(B
:_singleton e$B$O$b$C$HIT5$L#$G!”$K$b4X$o$i$:;H$$$I$3$m$,e(B
e$B$"$^$j;W$$$D$-$^$;$s!#e(B

e$B0lHL$K!"0lIt$r=q$-49$($?$$$H$$$&$H$-$K$O>o$KLr$KN)$D$H;W$$$^e(B
e$B$9!#e(B

e$B0lIt$r=q$-49$($?$b$N$rF@$?$$$H$$$&$H$-$K$O!“=q$-49$($?$$$H$3e(B
e$B$m$@$1$G$J$/!”=q$-49$($?$/$J$$$H$3$m$bI,MW$G$9!#$3$l$O=q$-49e(B
e$B$($?$/$J$$$b$N$K$O$=$N$^$^=PNO$9$k$H$$$&=hM}$,I,MW$@$+$i$G$9!#e(B
e$B$=$&$$$&!"6=L#$NBP>]$G$J$$$H$3$m$K<j4V$,$+$+$k$N$O$h$m$7$/$"e(B
e$B$j$^$;$s!#e(B

_ e$B$G;O$^$k%7%s%%k$J$i!"$$$+$K$bFC<l$J0UL#$r;}$C$F$$$=$&$Je(B
e$B%*!<%i$,=P$F$k$N$G!"5v$;$k5$$b$7$F$-$^$7$?!#e(B
e$B$$$$2C8:$G$9$_$^$;$s!#e(B

e$B$=$&$$$&0u>]$O<B:]$K1F6A$r;}$C$F$$$k$H;W$$$^$9!#5!G=$NM-L5$@e(B
e$B$1$G$J$/!"$=$&$$$&B&LL$b5DO@$G$-$k$H$$$$$G$9$M!#e(B

Tanaka_A · May 17, 2009, 2:26pm

In article [email protected],
Yukihiro M. [email protected] writes:

e$B$9$G$K=P$F$$$?e(Bslice_bye$B$H$+$,$$$$$h$&$J5$$b$7$^$9!#e(B

e$B$,!"EDCf$5$s$,Ds0F$7$F$$$k5!G=A4Ite(B(e$BMWAG:o=|$H$+e(B)e$B$Oe(Bslice_bye$B$Ge(B
e$B$OI=8=$7$-$l$J$$$h$&$J5$$b$7$^$9$,!#e(B

e$B$Ge(B slice e$B$r$R$/$H!"e(B

 to cut off or remove as a slice or slices (sometimes fol. by

off, away, from, etc.).

e$B$H$"$k$N$G!“e(Bslice e$B$b:o=|$N0UL#$K;H$&$3$H$O$”$k$h$&$G$9!#e(B

Enumerable#gather_each

ã¨ã„ã†ã‹ã€ã“ã‚Œã£ã¦ãƒãƒƒãƒ•ã‚¡ã¯åˆ¥ã«æä¾›ã—ã¦ã€

Enumerableç‰ˆinjectã§ã‚„ã‚‹ã¹ããªæ°—ã‚‚

% svn diff --diff-cmd diff -x ‘-u -p’ Index: enum.c

[2, 3] # 2 & 2 = 3 & 2 = 1

[4, 5] # 4 & 2 = 5 & 2 = 0

[6, 7] # 6 & 2 = 7 & 2 = 1

[8, 9] # 8 & 2 = 9 & 2 = 0

[10] # 10 & 2 = 1

gather indented blocks.

% svn diff --diff-cmd diff -x ‘-u -p’ Index: enum.c

[2, 3] # 2 & 2 = 3 & 2 = 1

[4, 5] # 4 & 2 = 5 & 2 = 0

[6, 7] # 6 & 2 = 7 & 2 = 1

[8, 9] # 8 & 2 = 9 & 2 = 0

[10] # 10 & 2 = 1

gather indented blocks.

iterate over svn log entries.

iterate over ChangeLog entries.

split mails in mbox (slice before Unix From line after an empty

% svn diff --diff-cmd diff -x ‘-u -p’ Index: enum.c

[2, 3] # 2 & 2 = 3 & 2 = 1

[4, 5] # 4 & 2 = 5 & 2 = 0

[6, 7] # 6 & 2 = 7 & 2 = 1

[8, 9] # 8 & 2 = 9 & 2 = 0

[10] # 10 & 2 = 1

gather indented blocks.

iterate over svn log entries.

iterate over ChangeLog entries.

parse mbox

split mails in mbox (slice before Unix From line after an empty

ã¨ã„ã†ã‹ã€ã“ã‚Œã£ã¦ãƒãƒƒãƒ•ã‚¡ã¯åˆ¥ã«æä¾›ã—ã¦ã€

Enumerableç‰ˆinjectã§ã‚„ã‚‹ã¹ããªæ°—ã‚‚

% svn diff --diff-cmd diff -x ‘-u -p’
Index: enum.c

% svn diff --diff-cmd diff -x ‘-u -p’
Index: enum.c

% svn diff --diff-cmd diff -x ‘-u -p’
Index: enum.c