GADT.ppt
Generalised Algebraic Data Types Simon Peyton Jones Microsoft Research Geoffrey Washburn University of Pennsylvania Stephanie Weirich University of Pennsylvania A typical evaluator data Term = Lit Int | Succ Term | IsZero Term | If Term Term Term data Value = VInt Int | VBool Bool eval :: Term -> Value eval (Lit i) = VInt i eval (Succ t) = case eval t of { VInt i -> VInt (i+1) } eval (IsZero t) =
Haskell/GADT - Wikibooks, open books for an open world
Generalized algebraic datatypes, or simply GADTs, are a generalization of the algebraic data types that you are familiar with. Basically, they allow you to explicitly write down the types of the constructors. In this chapter, you'll learn why this is useful and how to declare your own. We begin with an example of building a simple embedded domain specific language (EDSL) for simple arithmetical ex
Haskell+GADTã§å®šç†è¨¼æ˜Ž ãã®1: 型レベル自然数ã®ç‰ä¾¡æ€§ - keigoiã®æ—¥è¨˜
実ã¯ã€ç§ã®full-sessionsã¨ã„ã†ã‚»ãƒƒã‚·ãƒ§ãƒ³åž‹ã®ãƒ©ã‚¤ãƒ–ラリã¯ä¸ã§ unsafeCoerce#を使ã£ã¦ã„ã‚‹ã®ã§åž‹å®‰å…¨ã§ãªã„。使ã£ã¦ãれる人ã«ã¨ã£ã¦ãã‚Œã¯å¿ƒã‚‚ã¨ãªã„ã ã‚ã†ã—ã€ãã‚‚ãã‚‚unsafeãªã‚“ã¨ã‹ã¯ã€ã„ã‘ãŒã¿ã•ã‚“ã«ã‚ˆã‚Œã°SPJã¨Simon Marlowã—ã‹ä½¿ã£ã¦ã¯ã„ã‘ãªã„ã“ã¨ã«ãªã£ã¦ã„るらã—ã„。やã£ã±ã‚ŠHaskellを使ã†ã‚‚ã®ã¨ã—ã¦åž‹å®‰å…¨æ€§ãらã„ã¯ä¿è¨¼ã—ãŸã„。ã§ã‚‚ã€ã‹ã¨ã„ã£ã¦æ™®é€šã®Haskellã§ã¯ã†ã¾ã型を付ã‘られãªã„。(Typeableクラスã®ã‚ャストを使ã£ã¦ã‚‚解決ã«ã¯ãªã‚‰ãªã„。) ãã“ã§ã€é”法ã®GADT。 ã“ã®åž‹ã¨ã“ã®åž‹ã¯ãœã£ãŸã„ç‰ã—ã„ã®ã«ãƒ¼ã¨ã„ã†ã®ãŒæ–‡è„ˆã‹ã‚‰æ˜Žã‚‰ã‹ãªã¨ãã€ãれを表ç¾ã§ãã‚‹ã®ãŒGADTã …ã¨ã„ã†ã®ãŒç§ã®ç†è§£ã€‚ã¾ã•ã—ãç§ã®ã‚±ãƒ¼ã‚¹ã«ã´ã£ãŸã‚Šã 。ã“れを使ãˆã°unsafeCoerceãªã‚“ã‹è¦ã‚‰ã‚“ã‹ã‚‚ã—ã‚Œãªã„。 ã„ã„ã‹ãˆã‚Œã°ã€ã„ã‚ゆる定ç†è¨¼æ˜Žã‚’GADTã¤ãã®Haske
1
ãŠçŸ¥ã‚‰ã›
ランã‚ング
ランã‚ング
リリースã€éšœå®³æƒ…å ±ãªã©ã®ã‚µãƒ¼ãƒ“スã®ãŠçŸ¥ã‚‰ã›
最新ã®äººæ°—エントリーã®é…ä¿¡
処ç†ã‚’実行ä¸ã§ã™
j次ã®ãƒ–ックマーク
kå‰ã®ãƒ–ックマーク
lã‚ã¨ã§èªã‚€
eコメント一覧を開ã
oページを開ã
https://www.math.nagoya-u.ac.jp/~garrigue/papers/mlmt.pdf
{{#tags}}- {{label}}
{{/tags}}