{"id":4520,"date":"2026-06-24T07:00:00","date_gmt":"2026-06-23T22:00:00","guid":{"rendered":"https:\/\/litcoder.com\/?p=4520"},"modified":"2026-05-30T22:38:18","modified_gmt":"2026-05-30T13:38:18","slug":"rust-%ed%94%84%eb%a1%9c%ea%b7%b8%eb%9e%98%eb%b0%8d-%ec%bd%94%eb%93%9c-%ea%b0%80%eb%8f%85%ec%84%b1%ec%9d%84-%eb%86%92%ec%9d%b4%ea%b8%b0-%ec%9c%84%ed%95%9c-and_then-%ed%99%9c%ec%9a%a9","status":"publish","type":"post","link":"https:\/\/litcoder.com\/?p=4520","title":{"rendered":"Rust \ud504\ub85c\uadf8\ub798\ubc0d, \ucf54\ub4dc \uac00\ub3c5\uc131\uc744 \ub192\uc774\uae30 \uc704\ud55c and_then() \ud65c\uc6a9"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">Rust\ub294 \uc120\uc5b8\uc801 \ud504\ub85c\uadf8\ub798\ubc0d\uc744 \uc801\uadf9\uc801\uc73c\ub85c \uc0ac\uc6a9\ud558\uae30\uc5d0 method chaining\uc744 \ub9ce\uc774 \uc0ac\uc6a9\ud558\ub294\ub370 \uc774\ub294 \uac00\ub3c5\uc131\uc744 \ub192\uc774\uace0 \ucef4\ud30c\uc77c\ub7ec\uac00 \ucd5c\uc801\ud654\ub97c \uc218\ud589\ud558\ub294\ub370 \uc801\ud569\ud55c \ud615\ud0dc\uc774\uae30 \ub54c\ubb38\uc774\ub2e4. \uc774 \ud3ec\uc2a4\ud305\uc5d0\uc11c\ub294 method chaining\uc744 \uc720\uc9c0\ud558\uba74\uc11c\ub3c4 \uc911\ucca9\ub41c <code>Result<\/code> \ud639\uc740 <code>Option<\/code> \ud615\uc2dd\uc744 \ud53c\ud560 \uc218 \uc788\ub294 <code>and_then()<\/code>\uc5d0 \ub300\ud574 \uc54c\uc544\ubcf8\ub2e4.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">match \ubb38\uc744 \uc774\uc6a9\ud55c \ucc98\ub9ac<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">\uc138\uac1c\uc758 \ud568\uc218 \uac01\uac01\uc774 \ub2e4\uc74c\uacfc \uac19\uc774 <code>Result<\/code>\ub97c \ubc18\ud658\ud55c\ub2e4\uace0 \ud574\ubcf4\uc790.<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"rust\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">use std::io::{Error, ErrorKind};\n\n\/\/\/ 1. \uc785\ub825\ub41c \uc0ac\uc6a9\uc790 JSON \uac80\uc99d, \ube48 \ubb38\uc790\uc5f4\uc774 \uc544\ub2c8\uba74 Ok \ubc18\ud658.\nfn validate_json(raw: &amp;str) -> Result&lt;&amp;str, Error> {\n  if raw.is_empty() {\n    Err(Error::new(ErrorKind::InvalidData, \"empty user input\"))\n  } else {\n    Ok(raw)\n  }\n}\n\n\/\/\/ 2. \uc0ac\uc6a9\uc790 id \ubc18\ud658\nfn get_user_id(username: &amp;str) -> Result&lt;u32, Error> {\n  if username == \"admin\" {\n    Ok(1)\n  } else {\n    Err(Error::new(ErrorKind::NotFound, \"user not found\"))\n  }\n}\n\n\/\/\/ 3. \ud1a0\ud070 \uc0dd\uc131\nfn generate_token(user_id: u32) -> Result&lt;String, Error> {\n  if user_id == 1 {\n    Ok(format!(\"token_for_user_{}\", user_id))\n  } else {\n    Err(Error::new(ErrorKind::InvalidInput, \"user id unavailable\"))\n  }\n}<\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">\uac01 \ud568\uc218\ub4e4\uc740 1. \uc720\ud6a8\ud55c JSON\uc778\uc9c0 \ud310\ubcc4\ud558\uace0, 2. \uc0ac\uc6a9\uc790\ub97c \uac80\uc0c9\ud574\uc11c id\ub97c \ubc18\ud658\ud55c \ud6c4, 3. \ud574\ub2f9 \uc0ac\uc6a9\uc790\uc5d0 \ub300\ud55c \ud1a0\ud070\uc744 \uc0dd\uc131\ud574\uc11c \ubc18\ud658\ud55c\ub2e4.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\uc774\ub97c <code>match<\/code> \ubb38\uc744 \uc774\uc6a9\ud574\uc11c \ucc98\ub9ac \ud558\uba74 \ub2e4\uc74c\uacfc \uac19\uc774 \ub420 \uac83\uc774\ub2e4.<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"rust\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">fn main() {\n  let raw_input = \"admin\";\n\n  \/\/ 1. JSON \uc720\ud6a8\uc131 \ud310\ubcc4\n  match validate_json(raw_input) {\n    Ok(user) => {\n      \/\/ 2. \uc720\ud6a8\ud558\uba74 \uc0ac\uc6a9\uc790 id \uac80\uc0c9\n      match get_user_id(user) {\n        Ok(id) => {\n          \/\/ 3. \uc0ac\uc6a9\uc790\uac00 \uc720\ud6a8\ud558\uba74 \ud1a0\ud070 \uc0dd\uc131\n          match generate_token(id) {\n            Ok(tok) => {\n              \/\/ \ud1a0\ud070 \ucd9c\ub825\n              println!(\"{:?}\", tok);\n            },\n            \/\/ \ud1a0\ud070 \uc0dd\uc131\uc2dc \uc5d0\ub7ec \ucc98\ub9ac\n            Err(e) => eprint!(\"Error: {e}\")\n          }\n        },\n        \/\/ \uc720\ud6a8\ud558\uc9c0 \uc54a\uc740 \uc0ac\uc6a9\uc790\n        Err(e) => eprint!(\"Error: {e}\")\n      }\n    },\n    \/\/ JSON\uc774 \uc720\ud6a8\ud558\uc9c0 \uc54a\uc74c\n    Err(e) => eprint!(\"Error: {e}\")\n    }\n  }\n}<\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">\ubaa8\ub4e0 <strong>match arm<\/strong>\ub4e4\uc744 \uba85\uc2dc\ud574\uc57c \ud558\ub294 match \uad6c\ubb38\uc758 \uc81c\uc57d \ub54c\ubb38\uc5d0 <code>Result<\/code>\uc758 <code>Ok<\/code>\uc640 <code>Err<\/code>\uc5d0 \ub300\ud55c \uacbd\uc6b0\ub97c \ubaa8\ub450 \uc801\uc5b4 \uc8fc\uc5b4\uc57c \ud558\uace0 \uc774 \ub54c\ubb38\uc5d0 \ucf54\ub4dc\uac00 \uc7a5\ud669\ud558\uace0 \uac00\ub3c5\uc131\uc774 \ub5a8\uc5b4\uc9c4\ub2e4.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">map() \ud65c\uc6a9<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">\uc774\uc804\uc758 &#8220;<a href=\"https:\/\/litcoder.com\/?p=4374\" data-type=\"link\" data-id=\"https:\/\/litcoder.com\/?p=4374\">Rust \ud504\ub85c\uadf8\ub798\ubc0d\uc5d0\uc11c map() \ud65c\uc6a9<\/a>&#8221; \uc5d0\uc11c \uc5b8\uae09 \ud588\ub4ef\uc774 <code>map()<\/code>\uc740 container\ubfd0\ub9cc \uc544\ub2c8\ub77c <code>Result<\/code>\ub098 <code>Option<\/code>\uc758 <code>Ok<\/code> \/ <code>Some<\/code>\uc778 \uacbd\uc6b0 \ub3d9\uc791\uc744 \uc815\uc758\ud558\ub294\ub370 \uc0ac\uc6a9\ud560 \uc218 \uc788\ub2e4. \ub530\ub77c\uc11c <code>map()<\/code>\uc744 \uc774\uc6a9\ud558\uba74 \ub2e4\uc74c\uacfc \uac19\uc774 \uc791\uc131\ud560 \uc218 \uc788\ub2e4.<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"rust\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">fn main() {\n  let raw_input = \"admin\";\n\n  let tok = validate_json(raw_input)\n      .map(|user| get_user_id(user)\n      .map(|id| generate_token(id)));\n\n  \/\/ Ok(Ok(Ok(\"token_for_user_1\")))\n  print!(\"{:?}\", tok);\n}<\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">\ubcf4\uae30\uc5d0\ub294 \ud6e8\uc52c \uae54\ub054\ud574 \uc84c\uc9c0\ub9cc, \uac01 \ud568\uc218\ub4e4\uc774 <code>Result<\/code>\ub97c \ubc18\ud658\ud558\uae30 \ub54c\ubb38\uc5d0 <code>tok<\/code>\ubcc0\uc218\uc758 type\uc774 <code>Result&lt;Result&lt;Result&lt;String, ...>, ...>, ...><\/code> \uac19\uc740 \uc5ec\ub7ec\ubc88 \uc911\ucca9\ub41c \ud615\uc2dd\uc774 \ub418\uc5b4 \uc5ec\ub7ec\ubc88 unwrap \ud574\uc8fc\uc5b4\uc57c \ud558\ub294 \ubcf4\uae30 \uc2eb\uc740 \ud615\ud0dc\uac00 \ub41c\ub2e4.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">and_then() \ud65c\uc6a9<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">\uc774\ub807\uac8c method chaining\uc73c\ub85c \uc911\ucca9\ub41c <code>Result<\/code>\ub098 <code>Option<\/code>\uc774 \ubc18\ud658\ub418\ub294 \uacbd\uc6b0\uc5d0\ub294 <code>and_then()<\/code>\uc744 \uc0ac\uc6a9\ud574\ubcf4\uc790.<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"rust\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">fn main() {\n  let raw_input = \"admin\";\n\n  let tok = validate_json(raw_input)\n      .and_then(|user| get_user_id(user))\n      .and_then(|id| generate_token(id));\n \n  \/\/ Ok(\"token_for_user_1\")  \n  print!(\"{:?}\", tok);\n}<\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">\uc774\ub807\uac8c method chaining\uc744 \ud558\uba74 \uc911\ubcf5\ub41c \ubc18\ud658\ud615\uc2dd \ub4e4\uc774 \ubaa8\ub450 \uc81c\uac70\ub418\uace0 <code>Result&lt;String, Error> <\/code>\ud615\uc2dd\uc73c\ub85c <code>tok<\/code> \ubcc0\uc218\uac00 \ubc18\ud658\ub418\uc5b4 \ud6e8\uc52c \uac00\ub3c5\uc131 \ub192\uc740 \ucf54\ub4dc\ub97c \uc720\uc9c0\ud560 \uc218 \uc788\ub2e4.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">\uacb0\ub860<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\"><code>map()<\/code>\uacfc <code>and_then()<\/code>\uc740 \ubaa8\ub450 Rust\uc758 \uc120\uc5b8\ud615 \ud504\ub85c\uadf8\ub798\ubc0d\uc744 \uac00\ub2a5\ud558\uac8c \ud558\ub294 \uc911\uc694\ud55c \uc694\uc18c\ub85c \ube44\uc2b7\ud574 \ubcf4\uc774\uc9c0\ub9cc, closure\uac00 \ubb34\uc5c7\uc744 \ubc18\ud658\ud558\ub294\uac00\uc5d0 \ub530\ub77c \uadf8 \ud65c\uc6a9\uc774 \ub2ec\ub77c\uc9c4\ub2e4.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>map(): \ub0b4\ubd80 \uac12\uc758 \ud615\ud0dc\ub9cc \ubc14\uafc0\ub54c(\uc2e4\ud328 \uac00\ub2a5\uc131\uc774 \uc5c6\ub294 \ub2e8\uc21c \ubcc0\ud658)<\/li>\n\n\n\n<li>and_then(): \ubcc0\ud658 \uacfc\uc815\uc5d0\uc11c \ub610 \ub2e4\ub978 <code>Option<\/code>\uc774\ub098 <code>Result<\/code>\uac00 \ubc1c\uc0dd\ud560 \ub54c(\uc2e4\ud328 \uac00\ub2a5\uc131\uc774 \uc788\ub294 \uc5f0\uc1c4 \uc791\uc5c5)<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">\ub3d9\uc77c\ud55c \ucf54\ub4dc\ub97c <code>match<\/code>\ub098 <code>if let<\/code>\uc73c\ub85c \uc791\uc131\ud560 \uc218\ub3c4 \uc788\uc9c0\ub9cc, \uc774\ub978\ubc14 &#8220;match hell&#8221;\uc758 \uc870\uc9d0\uc774 \ubcf4\uc774\uace0 \uadf8\ub85c \uc778\ud574 \ucf54\ub4dc\uc758 \uac00\ub3c5\uc131\uc774 \ub5a8\uc5b4\uc9c4\ub2e4\uba74 <code>and_then()<\/code>\uc744 \ud65c\uc6a9\ud574 \ubcf4\uc790.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Rust\ub294 \uc120\uc5b8\uc801 \ud504\ub85c\uadf8\ub798\ubc0d\uc744 \uc801\uadf9\uc801\uc73c\ub85c \uc0ac\uc6a9\ud558\uae30\uc5d0 method chaining\uc744 \ub9ce\uc774 \uc0ac\uc6a9\ud558\ub294\ub370 \uc774\ub294 \uac00\ub3c5\uc131\uc744 \ub192\uc774\uace0 \ucef4\ud30c\uc77c\ub7ec\uac00 \ucd5c\uc801\ud654\ub97c \uc218\ud589\ud558\ub294\ub370 \uc801\ud569\ud55c \ud615\ud0dc\uc774\uae30 \ub54c\ubb38\uc774\ub2e4. \uc774 \ud3ec\uc2a4\ud305\uc5d0\uc11c\ub294 method chaining\uc744 \uc720\uc9c0\ud558\uba74\uc11c\ub3c4 \uc911\ucca9\ub41c Result \ud639\uc740 Option \ud615\uc2dd\uc744 \ud53c\ud560 \uc218 \uc788\ub294 and_then()\uc5d0 \ub300\ud574 \uc54c\uc544\ubcf8\ub2e4. match \ubb38\uc744 \uc774\uc6a9\ud55c \ucc98\ub9ac \uc138\uac1c\uc758 \ud568\uc218 \uac01\uac01\uc774 \ub2e4\uc74c\uacfc \uac19\uc774 Result\ub97c \ubc18\ud658\ud55c\ub2e4\uace0 \ud574\ubcf4\uc790. \uac01 \ud568\uc218\ub4e4\uc740 1. \uc720\ud6a8\ud55c JSON\uc778\uc9c0 \ud310\ubcc4\ud558\uace0, 2. \uc0ac\uc6a9\uc790\ub97c \uac80\uc0c9\ud574\uc11c [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_post_was_ever_published":false},"categories":[5],"tags":[450,432,442,451,423],"class_list":["post-4520","post","type-post","status-publish","format-standard","hentry","category-programming","tag-and_then","tag-map","tag-programming","tag-readability","tag-rust"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/litcoder.com\/index.php?rest_route=\/wp\/v2\/posts\/4520","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/litcoder.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/litcoder.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/litcoder.com\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/litcoder.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=4520"}],"version-history":[{"count":7,"href":"https:\/\/litcoder.com\/index.php?rest_route=\/wp\/v2\/posts\/4520\/revisions"}],"predecessor-version":[{"id":4527,"href":"https:\/\/litcoder.com\/index.php?rest_route=\/wp\/v2\/posts\/4520\/revisions\/4527"}],"wp:attachment":[{"href":"https:\/\/litcoder.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=4520"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/litcoder.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=4520"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/litcoder.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=4520"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}