From: Tanaka Akira <akr@...17n.org>
Date: 2002-06-07T15:27:46+09:00
Subject: [ruby-dev:17353] Re: blocks and local variables

In article <200206070615.g576F9f29792@sharui.nakada.kanuma.tochigi.jp>,
  nobu.nakada@nifty.ne.jp writes:

> $B%V%m%C%/$,$J$/$F$b$H$$$&$N$OF10U$7$^$9$,!"0l$D$N%9%3!<%W$G2?EY(B
> $B$bF1$8L>A0$,:FDj5A$5$l$F$+$D$=$l$,JL8D$KM-8z$H$$$&$N$O!"$$$/$i(B
> $B$J$s$G$b$d$d$3$72a$.$d$7$^$;$s$+!#(B

$B4X?t7?8@8l$G$O$4$/IaDL$NOC$G!"JL$K$d$d$3$72a$.$k$H$O;W$$$^$;$s$,!#(B

Scheme $B$G(B

(let ((x 1))
  (let ((plus1 (lambda (a) (+ a x))))
    (let ((x 2))
      (let ((plus2 (lambda (a) (+ a x))))
        (let ((x 3))
          (let ((plus3 (lambda (a) (+ a x))))
            ...))))))        

$B$"$k$$$O(B

(let* ((x 1)
       (plus1 (lambda (a) (+ a x)))
       (x 2)
       (plus2 (lambda (a) (+ a x)))
       (x 3)
       (plus3 (lambda (a) (+ a x))))
  ...)

$B$"$k$$$O(B Ocaml $B$G(B

  let x = 1 in
  let plus1 = fun a -> a + x in
  let x = 2 in
  let plus2 = fun a -> a + x in
  let x = 3 in
  let plus3 = fun a -> a + x in
  ...

$B$H$+!#$^$!!"<+L@$@$H$^$G$O$$$$$^$;$s$1$I!#(B

$BC<E*$K$$$($P!"$=$l$>$l$N(B := $B$d(B let $B$,%9%3!<%W$r:n$k$N$G0l$D$N%9%3!<%W(B
$B$G$O$J$$$o$1$G$9!#(B

$B$?$@!"(BRuby $B$@$H(B if $B$d(B while $BFb$G$NJQ?tDj5A$,2<$KH4$1$k$N$G$=$N$"$?$j$O(B
$BLdBj$G$9$M!#(B

  x := 1
  lambda {
    if ...
      x := 2
    else
      x = 3
    end
    x = 4
  }
-- 
[$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)