{"id":1092,"date":"2026-05-31T01:48:54","date_gmt":"2026-05-30T16:48:54","guid":{"rendered":"https:\/\/nangchang.nes.or.kr\/?p=1092"},"modified":"2026-05-31T01:48:54","modified_gmt":"2026-05-30T16:48:54","slug":"6%ed%8e%b8-%ed%81%b4%eb%a1%9c%ec%a0%80-%ec%9d%b4%eb%a6%84-%ec%97%86%eb%8a%94-%ed%95%a8%ec%88%98-%eb%b8%94%eb%a1%9d-escaping-%ec%ba%a1%ec%b2%98-%eb%a6%ac%ec%8a%a4%ed%8a%b8","status":"publish","type":"post","link":"https:\/\/nangchang.nes.or.kr\/?p=1092","title":{"rendered":"[6\ud3b8] \ud074\ub85c\uc800 \u2014 \uc774\ub984 \uc5c6\ub294 \ud568\uc218 \ube14\ub85d, @escaping, \ucea1\ucc98 \ub9ac\uc2a4\ud2b8"},"content":{"rendered":"
\n

\ud83e\udd16 \uc774 \uae00\uc740 Claude Code<\/a>(AI)\uac00 \uc791\uc131\ud569\ub2c8\ub2e4. | \uc2dc\ub9ac\uc988 \ubaa9\ucc28<\/a> | \uc774\uc804: 5\ud3b8<\/a><\/p>\n<\/blockquote>\n

5\ud3b8\uc5d0\uc11c \ud568\uc218\ub97c \ubcc0\uc218\uc5d0 \ub2f4\uc744 \uc218 \uc788\ub2e4\ub294 \uac83\uc744 \ubc30\uc6e0\uc2b5\ub2c8\ub2e4. \ud074\ub85c\uc800(closure)\ub294 \uadf8\uac83\uc758 \ud655\uc7a5\uc785\ub2c8\ub2e4. \uc774\ub984\uc744 \ubd99\uc774\uc9c0 \uc54a\uace0, \uadf8 \uc790\ub9ac\uc5d0\uc11c \ubc14\ub85c \uc815\uc758\ud574\uc11c \ub118\uae38 \uc218 \uc788\ub294 \ud568\uc218 \ube14\ub85d\uc785\ub2c8\ub2e4.<\/p>\n

Swift\uc5d0\uc11c map<\/code>, filter<\/code>, sort<\/code> \uac19\uc740 \uba54\uc11c\ub4dc\ub97c \uc4f8 \ub54c, \ube44\ub3d9\uae30 \uc791\uc5c5\uc758 \uc644\ub8cc \ucf5c\ubc31\uc744 \ub118\uae38 \ub54c, \ubc84\ud2bc\uc758 \ub3d9\uc791\uc744 \uc815\uc758\ud560 \ub54c \u2014 \ubaa8\ub450 \ud074\ub85c\uc800\ub97c \uc501\ub2c8\ub2e4. \ud074\ub85c\uc800\ub97c \uc774\ud574\ud558\uc9c0 \uc54a\uc73c\uba74 Swift \ucf54\ub4dc\uc758 \uc808\ubc18\uc744 \uc77d\uc744 \uc218 \uc5c6\uc2b5\ub2c8\ub2e4.<\/p>\n

\n

\ud074\ub85c\uc800 \uae30\ubcf8 \ubb38\ubc95<\/h2>\n

\ud074\ub85c\uc800\ub294 { }<\/code> \uc548\uc5d0 \ud30c\ub77c\ubbf8\ud130, \ubc18\ud658 \ud0c0\uc785, \ubcf8\ubb38\uc744 \ubaa8\ub450 \uc501\ub2c8\ub2e4.<\/p>\n

{ (\ud30c\ub77c\ubbf8\ud130) -> \ubc18\ud658\ud0c0\uc785 in\n    \ubcf8\ubb38\n}\n<\/code><\/pre>\n
5\ud3b8\uc5d0\uc11c \ud568\uc218\ub85c \ub9cc\ub4e4\uc5c8\ub358 \ub367\uc148\uc744 \ud074\ub85c\uc800\ub85c \uc4f0\uba74 \uc774\ub807\uc2b5\ub2c8\ub2e4.<\/p>\n
\/\/ \ud568\uc218 \ubc29\uc2dd\nfunc add(_ a: Int, _ b: Int) -> Int { a + b }\n\n\/\/ \ud074\ub85c\uc800 \ubc29\uc2dd\nlet add = { (a: Int, b: Int) -> Int in\n    return a + b\n}\n\nadd(3, 4)  \/\/ 7\n<\/code><\/pre>\n
\ud0c0\uc785\uc740 \ucee8\ud14d\uc2a4\ud2b8\uc5d0\uc11c \ucd94\ub860\ub420 \ub54c \uc0dd\ub7b5\ud560 \uc218 \uc788\uace0, \ud45c\ud604\uc2dd\uc774 \ud558\ub098\uba74 return<\/code>\ub3c4 \uc0dd\ub7b5\ub429\ub2c8\ub2e4.<\/p>\n
let add: (Int, Int) -> Int = { a, b in a + b }\n<\/code><\/pre>\n
\n
\ud6c4\ud589 \ud074\ub85c\uc800\uc640 \ucd95\uc57d \ubb38\ubc95<\/h2>\n
\ud074\ub85c\uc800\ub97c \ud568\uc218\uc758 \ub9c8\uc9c0\ub9c9 \uc778\uc790\ub85c \ub118\uae38 \ub54c\ub294 \uad04\ud638 \ubc16\uc73c\ub85c \uaebc\ub0b4 \uc4f8 \uc218 \uc788\uc2b5\ub2c8\ub2e4. \uc774\uac83\uc744 \ud6c4\ud589 \ud074\ub85c\uc800(trailing closure)<\/strong>\ub77c\uace0 \ud569\ub2c8\ub2e4.<\/p>\n
let numbers = [3, 1, 4, 1, 5, 9]\n\n\/\/ \uc77c\ubc18 \ubc29\uc2dd\nlet sorted = numbers.sorted(by: { (a: Int, b: Int) -> Bool in\n    return a < b\n})\n\n\/\/ \ud6c4\ud589 \ud074\ub85c\uc800\nlet sorted = numbers.sorted { (a: Int, b: Int) -> Bool in\n    return a < b\n}\n\n\/\/ \ud0c0\uc785 \ucd94\ub860\uc73c\ub85c \uc0dd\ub7b5\nlet sorted = numbers.sorted { a, b in a < b }\n\n\/\/ $0, $1 \ucd95\uc57d \uc778\uc790\nlet sorted = numbers.sorted { $0 < $1 }\n\n\/\/ \uc5f0\uc0b0\uc790 \ud568\uc218\ub85c \ub354 \uc9e7\uac8c\nlet sorted = numbers.sorted(by: <)\n<\/code><\/pre>\n
\ubaa8\ub450 \uc644\uc804\ud788 \ub3d9\uc77c\ud55c \ucf54\ub4dc\uc785\ub2c8\ub2e4. \uc0c1\ud669\uc5d0 \ub530\ub77c \uc801\uc808\ud55c \uc218\uc900\uc758 \ucd95\uc57d\uc744 \uc501\ub2c8\ub2e4. \ub108\ubb34 \uc904\uc774\uba74 \uc77d\uae30 \uc5b4\ub824\uc6cc\uc9c0\ubbc0\ub85c, \ud55c \uc904\uc5d0 \ub2e4 \ub4e4\uc5b4\uc624\uace0 \uc758\ubbf8\uac00 \uba85\ud655\ud560 \ub54c\ub9cc $0<\/code>, $1<\/code> \ucd95\uc57d\uc744 \uc501\ub2c8\ub2e4.<\/p>\n
3\ud3b8\uc5d0\uc11c \ubd24\ub358 map<\/code>, filter<\/code>\ub3c4 \ud074\ub85c\uc800\ub97c \ubc1b\ub294 \ud568\uc218\uc785\ub2c8\ub2e4.<\/p>\n
let numbers = [1, 2, 3, 4, 5]\n\nlet doubled = numbers.map { $0 * 2 }       \/\/ [2, 4, 6, 8, 10]\nlet evens   = numbers.filter { $0 % 2 == 0 } \/\/ [2, 4]\nlet total   = numbers.reduce(0) { $0 + $1 }  \/\/ 15\n<\/code><\/pre>\n
\n
\uac12 \ucea1\ucc98<\/h2>\n
\ud074\ub85c\uc800\ub294 \uc790\uc2e0\uc774 \uc815\uc758\ub41c \uc2a4\ucf54\ud504\uc758 \ubcc0\uc218\ub97c \ucea1\ucc98(capture)<\/strong>\ud569\ub2c8\ub2e4. \ud568\uc218\uac00 \ub05d\ub09c \ub4a4\uc5d0\ub3c4 \uadf8 \ubcc0\uc218\ub97c \uacc4\uc18d \ucc38\uc870\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n
func makeCounter() -> () -> Int {\n    var count = 0\n    let increment = {\n        count += 1\n        return count\n    }\n    return increment\n}\n\nlet counter = makeCounter()\nprint(counter())  \/\/ 1\nprint(counter())  \/\/ 2\nprint(counter())  \/\/ 3\n<\/code><\/pre>\n
makeCounter()<\/code>\uac00 \ubc18\ud658\ub418\uace0 \ub098\uc11c\ub3c4 \ud074\ub85c\uc800 increment<\/code>\ub294 count<\/code>\ub97c \uc0b4\uc544\uc788\uac8c \uc720\uc9c0\ud569\ub2c8\ub2e4. \ud074\ub85c\uc800\uac00 count<\/code>\ub97c \ucea1\ucc98\ud588\uae30 \ub54c\ubb38\uc785\ub2c8\ub2e4. Python\uc758 \ud074\ub85c\uc800\ub098 JavaScript\uc758 \ud074\ub85c\uc800\uc640 \ub3d9\uc77c\ud55c \uac1c\ub150\uc785\ub2c8\ub2e4.<\/p>\n
\n
@escaping \u2014 \ud074\ub85c\uc800\uac00 \ud568\uc218\ubcf4\ub2e4 \uc624\ub798 \uc0ac\ub294 \uacbd\uc6b0<\/h2>\n
\ud074\ub85c\uc800\ub97c \ud568\uc218 \uc778\uc790\ub85c \ubc1b\uc744 \ub54c, \uadf8 \ud074\ub85c\uc800\uac00 \ud568\uc218 \uc2e4\ud589\uc774 \ub05d\ub09c \ub4a4\uc5d0\ub3c4 \uc0b4\uc544\ub0a8\uc544\uc57c \ud55c\ub2e4\uba74 @escaping<\/code>\uc744 \ud45c\uc2dc\ud569\ub2c8\ub2e4.<\/p>\n
var completionHandlers: [() -> Void] = []\n\nfunc register(handler: @escaping () -> Void) {\n    completionHandlers.append(handler)  \/\/ \ud568\uc218 \uc885\ub8cc \ud6c4\uc5d0\ub3c4 handler\uac00 \uc0b4\uc544\ub0a8\uc74c\n}\n<\/code><\/pre>\n
\uac00\uc7a5 \ud754\ud55c \uc0ac\ub840\ub294 \ube44\ub3d9\uae30 \uc791\uc5c5\uc758 \uc644\ub8cc \ucf5c\ubc31\uc785\ub2c8\ub2e4.<\/p>\n
func fetchData(completion: @escaping (String) -> Void) {\n    DispatchQueue.global().async {\n        \/\/ \ubc31\uadf8\ub77c\uc6b4\ub4dc\uc5d0\uc11c \uc791\uc5c5\n        let result = \"\ub370\uc774\ud130\"\n        DispatchQueue.main.async {\n            completion(result)  \/\/ \ud568\uc218 \ubc18\ud658 \uc774\ud6c4\uc5d0 \ud638\ucd9c\ub428\n        }\n    }\n}\n<\/code><\/pre>\n
@escaping<\/code>\uc774 \uc5c6\ub294 \ud074\ub85c\uc800(non-escaping)\ub294 \ud568\uc218 \ub0b4\uc5d0\uc11c\ub9cc \uc2e4\ud589\ub418\uace0 \uc0ac\ub77c\uc9d1\ub2c8\ub2e4. Swift\uac00 \uae30\ubcf8\uc744 non-escaping\uc73c\ub85c \ub454 \uc774\uc720\ub294 \uc131\ub2a5 \ucd5c\uc801\ud654\uc640 \uba54\ubaa8\ub9ac \uc548\uc804\uc131 \ub54c\ubb38\uc785\ub2c8\ub2e4. \ud0c8\ucd9c\ud558\uc9c0 \uc54a\ub294\ub2e4\ub294 \ubcf4\uc7a5\uc774 \uc788\uc73c\uba74 \ucef4\ud30c\uc77c\ub7ec\uac00 \ub354 \uc801\uadf9\uc801\uc73c\ub85c \ucd5c\uc801\ud654\ud560 \uc218 \uc788\uc2b5\ub2c8\ub2e4.<\/p>\n
\n
\ucea1\ucc98 \ub9ac\uc2a4\ud2b8\uc640 [weak self]<\/h2>\n
\ud074\ub85c\uc800\uac00 \ud074\ub798\uc2a4 \uc778\uc2a4\ud134\uc2a4\ub97c \ucea1\ucc98\ud558\uba74 \uac15\ud55c \ucc38\uc870(strong reference)\uac00 \uc0dd\uae41\ub2c8\ub2e4. \uadf8 \uc778\uc2a4\ud134\uc2a4\uac00 \ud074\ub85c\uc800\ub97c \uc18c\uc720\ud558\uace0, \ud074\ub85c\uc800\uac00 \ub2e4\uc2dc \uadf8 \uc778\uc2a4\ud134\uc2a4\ub97c \ucc38\uc870\ud558\uba74 \uc21c\ud658 \ucc38\uc870(retain cycle)<\/strong>\uac00 \uc0dd\uaca8 \uba54\ubaa8\ub9ac \ub204\uc218\uac00 \ubc1c\uc0dd\ud569\ub2c8\ub2e4.<\/p>\n
class NetworkManager {\n    var onComplete: (() -> Void)?\n\n    func start() {\n        onComplete = {\n            print(self.description)  \/\/ self\ub97c \uac15\ud558\uac8c \ucea1\ucc98\n            \/\/ NetworkManager \u2192 onComplete \u2192 \ud074\ub85c\uc800 \u2192 NetworkManager \uc21c\ud658\n        }\n    }\n}\n<\/code><\/pre>\n
\uc774\ub97c \ub9c9\uae30 \uc704\ud574 \ucea1\ucc98 \ub9ac\uc2a4\ud2b8<\/strong>\ub85c \uc57d\ud55c \ucc38\uc870\ub97c \uc501\ub2c8\ub2e4.<\/p>\n
class NetworkManager {\n    var onComplete: (() -> Void)?\n\n    func start() {\n        onComplete = { [weak self] in\n            guard let self = self else { return }\n            print(self.description)\n        }\n    }\n}\n<\/code><\/pre>\n
[weak self]<\/code>\ub294 \"self\ub97c \uc57d\ud558\uac8c \ucea1\ucc98\ud55c\ub2e4\"\ub294 \uc120\uc5b8\uc785\ub2c8\ub2e4. \uc57d\ud55c \ucc38\uc870\ub294 \uc778\uc2a4\ud134\uc2a4\uac00 \ud574\uc81c\ub418\uba74 \uc790\ub3d9\uc73c\ub85c nil<\/code>\uc774 \ub429\ub2c8\ub2e4. \uadf8\ub798\uc11c guard let self = self<\/code>\ub85c \uba3c\uc800 nil \uc5ec\ubd80\ub97c \ud655\uc778\ud569\ub2c8\ub2e4.<\/p>\n
\uc5b8\uc81c [weak self]<\/code>\uac00 \ud544\uc694\ud55c\uac00:<\/p>\n