{"published":"2012-08-20 23:15:25","version":"1.0","image_url":null,"height":"190","html":"<iframe src=\"https://hatenablog-parts.com/embed?url=https%3A%2F%2Fc255.hatenablog.com%2Fentry%2F2012%2F08%2F20%2F231525\" title=\"\u306a\u305c Haskell \u306e (IO a) \u306f IO \u3067\u30d1\u30bf\u30fc\u30f3\u30de\u30c3\u30c1\u3067\u304d\u306a\u3044\u306e\u304b - \u3053\u3046\u3082\u308a\u304c\u3063\u3071\" class=\"embed-card embed-blogcard\" scrolling=\"no\" frameborder=\"0\" style=\"display: block; width: 100%; height: 190px; max-width: 500px; margin: 10px 0px;\"></iframe>","blog_title":"\u3053\u3046\u3082\u308a\u304c\u3063\u3071","blog_url":"https://c255.hatenablog.com/","provider_url":"https://hatena.blog","title":"\u306a\u305c Haskell \u306e (IO a) \u306f IO \u3067\u30d1\u30bf\u30fc\u30f3\u30de\u30c3\u30c1\u3067\u304d\u306a\u3044\u306e\u304b","width":"100%","url":"https://c255.hatenablog.com/entry/2012/08/20/231525","type":"rich","author_url":"https://blog.hatena.ne.jp/c255/","provider_name":"Hatena Blog","author_name":"c255","categories":["Haskell"],"description":"\u306a\u3093\u3066\u3053\u3068\u3092\u601d\u3063\u305f\u308f\u3051\u3067\u3059\u3002 \u3061\u3087\u3063\u3068\u8003\u3048\u308b\u3068\u305f\u3060\u306e\u52d8\u9055\u3044\u306a\u306e\u3067\u6065\u305a\u304b\u3057\u3044\u3067\u3059\u3002\u307e\u305a IO a \u306f\u305d\u3046\u3044\u3046\u578b\u540d\u306a\u306e\u3067\u3042\u3063\u3066 IO a \u3068\u3044\u3046\u578b\u30b3\u30f3\u30b9\u30c8\u30e9\u30af\u30bf\u3067\u306f\u306a\u3044\u3068\u3044\u3046\u3053\u3068\u3067\u3059\u3002 IO \u306e\u578b\u5b9a\u7fa9\u306f http://www.haskell.org/ghc/docs/latest/html/libraries/ghc-prim-0.2.0.0/src/GHC-Types.html#IO \u306b\u66f8\u3044\u3066\u3042\u308a\u307e\u3059\u304c\u3001\u3053\u3053\u3092\u898b\u308b\u3068\u308f\u304b\u308b\u3088\u3046\u306b newtype IO a = IO (State# RealWorld -> (# State# RealWorld, a #)) \u3068\u306a\u3063\u3066\u3044\u308b\u8a33\u3067\u3059\u306d\u3002 \u3053\u308c\u306f St\u2026"}