[haskell:45] Re: Haskell=?iso-2022-jp?B?GyRCJE5Ldkh4OkY1IhsoQg==?=

[Nobuo Yamashita]

nobsun 

> Haskell $B$G$O$3$l$r$I$&$7$F$$$k$+$O!"I8=`%W%l%j%e!<%I$N(B sum $B$NDj5A$r(B
> $B8+$l$P$o$+$j$^$9!#(B

$BI8=`%W%l%j%e!<%I$G$O!"(B

sum :: Num a => [a] -> a
sum = foldl' (+) 0

$B$G!"$3$3$K$"$k(B foldl' $B$O(B foldl $B$N%9%H%j%/%HHG(B($B!)(B)$B$G!"(B
$B$=$NDj5A$O(B

foldl' :: (a -> b -> a) -> a -> [b] -> a
foldl' f a []     = a
foldl' f a (x:xs) = (foldl' f $! f a x) xs

$B$3$3$G$b(B $! $B$H$$$&$"$d$7$$1i;;;R$,=P$F$-$^$7$?$,!"$3$l$O(B
$ $B$H$$$&(B lisp $B$N(B apply $B$K$"$?$k1i;;;R$N%9%H%j%/%HHG$G$9!#(B

($!) :: (a -> b) -> a -> b
f $! x = x `seq` f x

$B$G$9!#$3$N(B seq $B$H$$$&4X?t$,FC2A$7$F$+$i!"(Bf x $B$rI>2A$7$F(B
$B$=$NCM$rJV$9FCJL$J4X?t$G$9!#$3$l$O!"(BHaskell $B$N;EMM$K4^$^$l$F$$$^$9!#(B

$B$H$$$o$1$G!"(BHaskell $B$G$OItJ,E*$K%9%H%j%/%H$JI>2A$rhttp://QuickML.com/