単一スレッドでの逐次処理を保証していない。（想像です。）
次のようなスクリプトを書いてみた。
--a.hs
main = print [1..10]
--t.hs
import System.Process
loop x = createProcess (proc "runghc" ["a.hs"]) >> return ()
main = mapM_ loop [1..100]
実行結果。
$ runghc t.hs
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,[1,2,3,4,5,6,7,8,9,1[1,2,3,4,5,6,7,8,9,10]
5,6,7,8,9,10]
0]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,[1,2,3,4,5,6,7,8,9,10]
,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10[1,2,3,4[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4[1,2,3,4,5,6,7,8,9,10]
i@i:~/haskell$ [1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,,[1,2,3,4,5,6,7,8,9,10]
5,6,7,8,9,10]
]
[1,2,3,4,5,6,7,8,9,10]
,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3[1,2,3,4,5,6,7,8,9,10,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
,[1,2,3,4,5,6,7,8,9,10]
5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
]
[1,2,3,4,5,6,[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[[1,2,3,4,5,6,7,8,9,10]
1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,1[1,2,3,4,5,6,7,8,9,10]
7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
0[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
]
[1,2,3,4,5,6,7,8,9,10]
[[1,2,3,4,5,6,7,8,9,10]
1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8[1,2,3,4[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,,,5,6,[7,8,19,1,02]
,3,4,5,6,7,8,9,10]
9,10]
[1,2,3,4,5,6,7,8,9,10]
5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1,2,3,4,5,6,7,8,9,10]
[1..10]のリストを書き終える前に次のリストを書き始めている。
１００回のLoop の途中で t.hs スクリプトを終了している。
深い意味は僕には不明ですが、実用プログラムで使う場合には注意が必要なのでは・・・。
