GADTã§å®Ÿè¡Œæ™‚åž‹æƒ…å ±ã‚’è¡¨ç¾ã™ã‚‹ - Qiita
class Hoge { public static <A> A foo(A x) { if (x instanceof String) return null; return x; } public static void main(String[] args) { System.out.println(foo("Hello")); // -| null System.out.println(foo(42)); // -| 42 System.out.println(foo(new Object())); // -| java.lang.Object@15db9742 } } ã“ã®ä¾‹ã«ã¤ã„ã¦ã¯ã€é™çš„åž‹ã‹ã‚‰äºˆæƒ³ã•ã‚Œã‚‹æŒ™å‹•ã‚’è£åˆ‡ã‚‹ã‚ˆã†ãªãƒ—ãƒã‚°ãƒ©ãƒ ãŒæ›¸ã‘ã‚‹ã ã‘ã§ä½•ã‚‚嬉ã—ããªã„ã‘ã‚Œã©ã€æ™‚ã«ã¯å®Ÿè¡Œæ™‚åž‹æƒ…å ±ãŒä¾¿åˆ©ãªå ´åˆã‚‚ã‚る。 型を表ã™å€¤ 世ã®ä¸ã«ã¯å®Ÿè¡Œæ™‚åž‹æƒ…å ±ã®ã‚るジェãƒãƒªã‚¯ã‚¹ã‚’「真ã®ã‚¸ã‚§ãƒãƒªã‚¯ã‚¹
OCaml's `type a. a t` syntax
I've just come across the following code snippet in OCaml's documentation about GADTs: let rec eval : type a. a term -> a = function | Int n -> n | Add -> (fun x y -> x + y) | App (f, x) -> (eval f) (eval x) which, once evaluated in utop, has the following signature: val eval : 'a term -> 'a = <fun> I also noticed that, when replacing type a. a term -> a by 'a term -> 'a or just removing the signa
GADTを用ã„ãŸäºŒé …ヒープã®å®Ÿè£… - fetburner.core
ã“ã®ã‚¨ãƒ³ãƒˆãƒªã¯ML Advent Calendar 2015ã®14日目ã®è¨˜äº‹ã§ã™ã€‚ 13日目ã®è¨˜äº‹ã¯ã‚ˆã‚“ãŸã•ã‚“ã®é–¢æ•°åž‹ãƒ—ãƒã‚°ãƒ©ãƒŸãƒ³ã‚°ã«ãŠã‘ã‚‹å†å¸°é–¢æ•°ã®è€ƒãˆæ–¹ã§ã—ãŸã€‚ ML Advent Calendar 2015を追ã£ã¦ã„ã‚‹æ–¹ãªã‚‰å¤§ä½“察ã—ãŒä»˜ãã¨æ€ã„ã¾ã™ãŒã€ã“ã®è¨˜äº‹ã¯obj_magicã•ã‚“ã® A GADT implementation of AVL treeã«åˆºæ¿€ã‚’å—ã‘ã¦æ›¸ãã¾ã—ãŸã€‚ GADTã¨åž‹ãƒ¬ãƒ™ãƒ«è‡ªç„¶æ•°ã‚’使ã£ã¦AVL木を書ã‘ã‚‹ã®ãªã‚‰ã€ä»–ã®ãƒ‡ãƒ¼ã‚¿æ§‹é€ ã‚‚åŒã˜ãƒŽãƒªã§å®Ÿè£…ã—ã¦ã¿ã‚‹ã¨é¢ç™½ãã†ã ã¨æ€ã£ãŸã®ã§â€¦ã¾ã二番煎ã˜ã§ã™ã。 äºŒé …ãƒ’ãƒ¼ãƒ—ã¨ã¯ マージãŒé€Ÿã„ヒープã®å®Ÿè£…ã®ä¸€ç¨®ã‚‰ã—ã„ã§ã™ã€‚åƒ•ã‚‚äºŒé …ãƒ’ãƒ¼ãƒ—ã‚’å®Ÿè£…ã—ãŸã®ã¯ã“ã‚ŒãŒåˆã‚ã¦ã§è©³ã—ã„事ã¯åˆ†ã‹ã‚‰ãªã„ã®ã§ã€æ°—ã«ãªã£ãŸæ–¹ã¯ Amazon.co.jp： Purely Functional Data Structures: Chris Okasaki:
Google
世界ä¸ã®ã‚ã‚‰ã‚†ã‚‹æƒ…å ±ã‚’æ¤œç´¢ã™ã‚‹ãŸã‚ã®ãƒ„ールをæä¾›ã—ã¦ã„ã¾ã™ã€‚ã•ã¾ã–ã¾ãªæ¤œç´¢æ©Ÿèƒ½ã‚’活用ã—ã¦ã€ãŠæŽ¢ã—ã®æƒ…å ±ã‚’è¦‹ã¤ã‘ã¦ãã ã•ã„。
Sign in - Google Accounts
Not your computer? Use a private browsing window to sign in. Learn more about using Guest mode
Detecting use-cases for GADTs in OCaml
I’ve been interested in GADTs1 for quite some time now but I’ve had a hard time finding proper use-cases for them in my day-to-day programming tasks; this is not because GADTs aren’t useful, they are, but rather that my understanding of them has been limited. I often experience this when I’m learning more advanced features of programming languages and I’ve found that I personally find it easier to
Why GADTs matter for performance
When GADTs (Generalized Algebraic Data Types) landed in OCaml, I wasn’t particularly happy about it. I assumed that it was the kind of nonsense you get when you let compiler writers design your programming language. Which is to say that the standard GADT examples all seem to be about the kinds of things that compiler writers do, like embed domain-specific languages or build typed abstract-syntax t
OCamlã®GADTを試㙠- What is it, naokirin?
今回ã¯OCamlã®ç¾åœ¨ã®latest versionã§ã‚ã‚‹3.12.1ã«ã¯å®Ÿè£…ã•ã‚Œã¦ã„ãªã„ã€GADTã«ã¤ã„ã¦è©¦ã—ã¦ã¿ã¾ã—ãŸã€‚ ã¨ã‚Šã‚ãˆãšã€ç¾çŠ¶ã§OCamlã®GADTを試ã™ã«ã¯OCamlã®svnリãƒã‚¸ãƒˆãƒªã‹ã‚‰gadtsã‚’ã¨ã£ã¦ãã¦ãƒ“ルドã¨ã‚¤ãƒ³ã‚¹ãƒˆãƒ¼ãƒ«ã‚’è¡Œã†å¿…è¦ãŒã‚ã‚Šã¾ã™ã€‚ ãŸã ã—ã€ã“れを行ã†ã¨ã€ä»Šã¾ã§å…¥ã‚Œã¦ã„ãŸæ¨™æº–ã§ãªã„ライブラリã®ã†ã¡ã€cmiファイルãŒé–¢ä¿‚ã™ã‚‹ãƒ©ã‚¤ãƒ–ラリã¯ã»ã¼å…¨æ»…ã—ã¾ã™ï¼ˆå¤šåˆ†ï¼‰ã€‚ã¤ã¾ã‚Šè‡ªåŠ›ã§å…¥ã‚Œç›´ã—ã§ã™ã€‚ãã‚Œã«ãƒãƒ¼ã‚¸ãƒ§ãƒ³åãŒå¤‰æ›´ã•ã‚ŒãŸã‚Šã™ã‚‹é–¢ä¿‚ã§oasisパッケージã§OCamlã®ãƒãƒ¼ã‚¸ãƒ§ãƒ³æŒ‡å®šãŒã‚ã‚‹å ´åˆã€ãã®ã¾ã¾ã§ã¯å¯¾å¿œã—ã¦ã„ãªã„ãƒãƒ¼ã‚¸ãƒ§ãƒ³ã¨ã—ã¦æ‰±ã‚れるãªã©ã®å•é¡ŒãŒã‚ã‚Šã¾ã™ã€‚ç¾çŠ¶ã€ãã®ã¾ã¾æ™®æ®µã®é–‹ç™ºã§ä½¿ã†ã«ã¯ã‹ãªã‚Šè‡ªåŠ›ã§ã®è§£æ±ºãŒå¿…è¦ã«ãªã‚Šãã†ã§ã™ã€‚ ãã‚Œã§ã¯ä»¥ä¸Šã®ã“ã¨ã«æ³¨æ„ã—ãªãŒã‚‰ã€GADT対応ãƒãƒ¼ã‚¸ãƒ§ãƒ³ã‚’入れã¦ã¿ã¾ã™ã€‚ $ svn co http://caml.inria
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¿¡
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
Simple lambda calculus DSL using GADTs in OCaml
gadt_interp.ml
Reddit - Dive into anything
How to use GADTs across modules in OCaml without raising warnings?
How to resolve ambiguity in my GADTs
Practicalities and trade-offs in programming with GADTs
OCaml Briefly
https://objmagic.ml/2015/12/07/A-GADT-implementation-of-AVL-tree.html
https://okmij.org/ftp/ML/GADT.ml
Playing with OCaml GADTs
An concrete simple example to demonstrate GADT in OCaml?
Reddit - Dive into anything
{{#tags}}- {{label}}
{{/tags}}