{"provider_url":"https://hatena.blog","published":"2014-10-03 01:00:00","author_name":"mbps","author_url":"https://blog.hatena.ne.jp/mbps/","version":"1.0","blog_title":"PS","provider_name":"Hatena Blog","url":"https://mbps.hatenablog.com/entry/2014/10/03/010000","type":"rich","width":"100%","categories":["\u570f\u8ad6","F-algebra","Haskell"],"title":"GADTs","html":"<iframe src=\"https://hatenablog-parts.com/embed?url=https%3A%2F%2Fmbps.hatenablog.com%2Fentry%2F2014%2F10%2F03%2F010000\" title=\"GADTs - PS\" class=\"embed-card embed-blogcard\" scrolling=\"no\" frameborder=\"0\" style=\"display: block; width: 100%; height: 190px; max-width: 500px; margin: 10px 0px;\"></iframe>","height":"190","image_url":"http://chart.apis.google.com/chart?cht=tx&chl=%20%5Cmathrm%7BNat%7D%28%5Cmathcal%7BHask%7D%28x%2C%20%5Cunicode%7Bx2013%7D%29%2C%20%5Cmathtt%7BIntList%7D%29%20%5Ccong%20%5Cmathtt%7BIntList%7D%28x%29%20","blog_url":"https://mbps.hatenablog.com/","description":"\u8907\u96d1\u306aGADTs\u306fYoneda lemma\u3092\u4f7f\u3063\u3066Inductive family of types - PS\u306b\u3082\u3063\u3066\u3044\u3051\u308b\u3001\u3068\u3044\u3046\u3053\u3068\u3089\u3057\u3044\u3002 \u4f8b data Z data S n data IntList n where Nil :: IntList Z Cons :: Int -> IntList m -> IntList (S m) Covariant Yoneda lemma: \u3092\u3053\u3063\u305d\u308a\u4f7f\u3063\u3066 *1 \u306b\u5909\u5f62\u3059\u308b\u3068\u3001\u3053\u308c\u306fInductive family of types - PS\u3002 \u53c2\u8003\u6587\u732e Haskell for all: GADTs *1:natural transformati\u2026"}