From: Tanaka Akira <akr@...17n.org>
Date: 2001-06-09T22:34:40+09:00
Subject: [ruby-dev:13528] Re: yield *[[]]

In article <992022213.746115.25347.nullmailer@ev.netlab.zetabits.com>,
  matz@zetabits.com (Yukihiro Matsumoto) writes:

> |asgn.rb $B$rFI$s$G$_$^$7$?$,(B... $B$J$s$H$$$&$+(B nil.to_a $B$,(B [] $B$G$"$k$3$H$r(B
> |$B9*$_$KMxMQ$7$?;EMM$G$9$M$'!#$$$^$N$H$3$m7j$O8+Ev$?$j$^$;$s!#(B
> 
> $B:#$^$G$A$c$s$H9M$($F$J$+$C$?$s$G!"NI$$5!2q$G$7$?!#(B

$B$5$i$K8!F$$7$F$_$?$H$3$m!"$$$/$D$+5?Ld$,M/$$$F$-$^$7$?!#(B

(1) ... = arg, *[] $B$N5sF0(B

% ruby -e 'a, b = [1, 2], *[]; p [a,b]'
[[1, 2], nil]

*[] $B$,E83+$5$l$F>C$($k$H$9$l$P!"(B[1, 2] $B$HI=<($5$l$k$H$$$&$N$,0U?^$9$k(B
$B5sF0$J5$$,$7$^$9!#(B

(2) ... = ..., *non-array $B$N5sF0(B

% ruby -e 'a, b = 1, *2'
-e:1: failed to convert Fixnum into Array (TypeError)

* $B$,1&JU@hF,$K$"$k>l9g$K$ONc30$,5/$-$J$$$N$G0l4S@-$K7g$1$k$H46$8$^$9!#(B
$B$=$b$=$b!VG[Ns$X$NJQ49!W$H$$$&$N$O$I$N$h$&$K$7$F9T$J$o$l$k$N$G$7$g$&$+(B?

(3) $B<+8JBeF~$N1&JU$GJ#?t$N<0$,07$($F$b$$$$5$$,$9$k!%(B

  % ruby -e 'a = [1]; a += 2, 3; p a'        
  -e:1: parse error

$B$b$O$dB?=EBeF~$N1&JU$O$J$s$i$+$N(B($B$R$H$D$N(B)$BCM$r@8@.$9$k$?$a$N7A<0$J$N$G!"(B
$B<+8JBeF~$N1&JU$K;H$($J$$M}M3$O$J$$$H;W$$$^$9!#(B

(4) Proc $B$H$N4XO"@-(B

    self[arg ...]
    call(arg ... )
        $B<jB3$-%*%V%8%'%/%H$r<B9T$7$^$9!%0z?t$O%V%m%C%/$N0z?t$K$=$N$^$^(B
        ($BB?=EBeF~$N%k!<%k$K=>$$(B)$BBeF~$5$l$^$9!%(B

$B$H$$$&%^%K%e%"%k$N5-=R$O$b$O$dL@$i$+$K@5$7$/$"$j$^$;$s!#(B
($B0JA0@5$7$+$C$?$N$+$I$&$+$b2x$7$$$H$3$m$G$9$,!#(B)

% ruby -e 'lambda {|a,| p a}.call([1,2,3])'  
[1, 2, 3]
% ruby -e 'a, = [1,2,3]; p a'
1

% ruby -e 'a, = 1,2,3; p a'     
1
% ruby -e 'lambda {|a,| p a}.call(1,2,3)'  
-e:1: wrong # of arguments (3 for 1) (ArgumentError)
        from -e:1:in `call'
        from -e:1

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      $B<0(B

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      [$B:8JU<0(B `,' ...] `*' [$B:8JU<0(B]

    $B1&JU<0$NJ8K!(B:
      $B<0(B `,' $B<0(B [`,' $B<0(B ...]
      [$B<0(B `,' ...] `*' $B<0(B

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    $B$I$A$i$+$K$G$bJ#?t$N<0$,$"$k>l9g$NBeF~$rB?=EBeF~$H$$$$$^$9!#(B

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    $BE83+8e!"1&JU$K<0$,$J$/$J$C$?>l9g!"(Bnil $B$,1&JU$NCM$K$J$j$^$9!#(B
    $B1&JU$N<0$,$R$H$D$K$J$C$?>l9g$O$=$N<0$NCM$,1&JU$NCM$K$J$j$^$9!#(B
    $B1&JU$KJ#?t$N<0$,$"$k>l9g$O$=$l$i$NG[Ns$,1&JU$NCM$K$J$j$^$9!#(B

    $B$D$^$j!"1&JU<0$,!V<0(B1 `,' ... `,' $B<0(Bn$B!W$H$$$&7A$G$"$C$?>l9g!"(B
    [$B<0(B1$B$NCM(B, ..., $B<0(Bn$B$NCM(B] $B$H$$$&G[Ns$,1&JU$NCM$K$J$j$^$9!#(B

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    nil $B$,1&JU$NCM$K$J$j$^$9!#(B
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    $B<0(B1 $B$NCM<+BN$,1&JU$NCM$H$J$j$^$9!#(B

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    $B$+$C$3$G3g$kI,MW$,$"$j$^$9!#(B

> $B0U30$G$9$,!"(BPython$B$G$b5v$5$l$F$$$k$N$G$9!#(BPython$B$N>l9g(B
> formal argument$B$K$b$G$-$k$H;W$&!#(B

$B$"$!!"$=$&$$$d(B Python $B$G$b$G$-$^$9$M!#K:$l$F$^$7$?!#@N$OCN$C$F$$$?$O$:(B
$B$J$s$G$9$,!"$<$s$<$s;W$$=P$7$^$;$s$G$7$?!#$+$o$j$K(B ML $B$r;W$$=P$7$^$7$?(B
$B$,!#(B
-- 
[$BEDCf(B $BE/(B][$B$?$J$+(B $B$"$-$i(B][Tanaka Akira]
$B!V$U$($m(B! $B$o$+$a$A$c$s:n@o$G$9$(C"=$B!W(B(Little Worker, $B7KM7@84](B)