scalafmtについて調べてみた

Scala関西勉強会 - Summit直前スペシャルでの発表資料。

https://connpass.com/event/103702/

Transcript

1. scalafmtʹ͍ͭͯ ௐ΂ͯΈͨ Hirotaka Nosato
2. - nosatohirotaka @nosattee MOTEX Inc. Scalaྺ 4೥໨ Python Go Elasticsearch AWS ͜͏͍͏ਓ
3. ͱ͏ͩΜ͍͖ͭ͞ ;: ʮొஃऀ͕ɺొஃऀ͕͊͊͊͊ɾɾʯ ͷ: ʮ΍ɺ΍Γ·͢ʂʂʯ ͲɺͲ͏͠Α͏ɾɾ ࠷ۙ·ͱ΋ʹScala͞ΘͬͯͶ͐ɾɾ → ొஃΤϯτϦʔۦಈֶश΁
4. ൃද಺༰ީิͨͪ • ಈ͔͠ͳ͕ΒLagom FrameworkͷงғؾΛ௫Ή • https://github.com/lagom/online-auction-scala • alpakka elasticsearchίωΫλΛ࢖ͬͯΈͯงғؾΛ௫Ή • https://developer.lightbend.com/docs/alpakka/ current/elasticsearch.html • ScalafmtΑ͘Θ͔ͬͯͳ͍ͷͰɺษڧͯ͠ΈΔ
5. ຊ୊
6. Scalafmt ઃఆ ͳΜͱͳ͘ Θ͔Δͷ΋ ͋Δ͚Ͳɺɺ ͳΜͧɾɾ?? ↓↓↓ ͜ΕΒʹ͍ͭͯ ௐ΂ͨ͜ͱ" Λઆ໌͍͖ͯ͠·͢ɻ # See http://scalameta.org/scalafmt/#Configuration style = defaultWithAlign maxColumn = 130 includeCurlyBraceInSelectChains = false newlines.penalizeSingleSelectMultiArgList = false align = most align.tokens = [ {code = "<-"}, {code = "="}, {code = ":"}, {code = "->"}, {code = "=>"} ] align.openParenCallSite = false rewrite.rules = [ SortImports ] project.git = true project.excludeFilters = ["target/"] 1 2 3 4 5 6 7
7. ͪͳΈʹɺɺɺ • addSbtPlugin("com.geirsson" % "sbt-scalafmt" % “1.5.1") ࢖ͬͯ· ͢ɻ • ެࣜΛݟΔͱɺʮ͍͔ͭ͘ʯͷઃఆํ๏ͱޮՌ͸ॻ͍ͯ·͢ɻ • http://scalameta.org/scalafmt/#Configuration • ͨͩɺͦͷઆ໌ͷதʹ͸ɺҎԼͷΑ͏ʹ͋Δɻ • To find all available configuration options, it's best to browse the source code of Scalafmt. A good place to start is ScalafmtConfig. Observe that this listing below is the top- level, there are more configuration options if you visited nested fields like spaces and newlines. • ιʔείʔυݟΖɻ • IntelliJͷPluginΛೖΕΔ͜ͱͰɺCtrl+Shift+l ͰscalafmtͰίʔυϑΥʔ Ϛοτ͔͚Ε·͢ɻ • build.sbtʹ scalafmtOnCompile := true Λॻ͘͜ͱͰɺίϯύΠϧ࣌ʹࣗ ಈతʹίʔυϑΥʔϚοτ͔͚Ε·͢ɻ
8. “True”ͷ৔߹: List(1) .map { x => x + 2 } .filter(_ > 2) includeCurlyBraceInSelectChains “False”ͷ৔߹: List(1).map { x => x + 2 }.filter(_ > 2) style mapͳͲʹ࢖͏தׅހϒϩοΫͷ ѻ͍ํΛܾΊΔɻ 1 2 ઃఆ஋: default defaultWithAlign Scala.js IntelliJ ͍͍ײ͡ͷઃఆΛͯ͘͠ΕΔ΋ͷ? ެࣜαΠτʹ͕ͬͭΓͨ͠આ໌ͳ͠ɻίʔυΛݟΔ͔͠ͳ͍ɾɾɻ
9. org.scalafmt.config.Newlines.scalaʹ͋Δઆ໌ * @param penalizeSingleSelectMultiArgList * If true, adds a penalty to newlines before a dot starting a select * chain of length one and argument list. The penalty matches the number * of arguments to the select chain application. * {{{ * // If true, favor * logger.elem(a, * b, * c) * // instead of * logger * .elem(a, b, c) * * // penalty is proportional to argument count, example: * logger.elem(a, b, c) // penalty 2 * logger.elem(a, b, c, d) // penalty 3, etc. * }}} * * If false, matches pre-v0.5 behavior. Note. this option may be * removed in a future release. 3 ެࣜαΠτʹ͕ͬͭΓͨ͠આ໌ͳ͠ɻ trueͷ৔߹͸ɺҾ਺͕ෳ਺͋Δͱ͖ʹվߦͯ͠੔ྻͤ͞Δ penalizeSingleSelectMultiArgList
10. align “none”ͷ৔߹: x match { case 2 => 22 case 22 => 222 } “some”ͷ৔߹(default): x match { case 2 => 22 case 22 => 222 } val x = 2 val xx = 22 case object B extends A case object BB extends A “more”ͷ৔߹: x match { case 1 => 1 -> 2 case 11 => 11 -> 22 } val x = 2 val xx = 22 case object B extends A case object BB extends A for { x <- List(1) yyy <- List(2) zzz <- new Integer { def value = 3 } } yield x * yyy “most”ͷ৔߹: x match { case 1 => 1 -> 2 case 11 => 11 -> 22 } val x = 2 val xx = 22 case object B extends A case object BB extends A for { x <- List(1) yyy <- List(2) zzz <- new Integer { def value = 3 } } yield x * yyy ΞϥΠϝϯτ(੔ྻ)ܥʹ͍ܾͭͯΊΔɻ 4
11. x match { case 1 => 1 -> 2 case 11 => 11 -> 22 } align.tokens = [ {code = "=>", owner = “Case"} ] ͱࢦఆͨ͠৔߹… align.openParenCallSite trueͷ৔߹: function(arg1, arg2, arg3) falseͷ৔߹: function( arg1, arg2, arg3 ) align.tokens ੔ྻͤ͞Δه߸ΛܾΊΔɻ ownerΛࢦఆ͠ͳ͚Ε͹શͯͷOwnerʹద༻͞ΕΔɻ খׅހ಺ͷཁૉͷ ੔ྻΛܾΊΔɻ 5 6 7 rewrite.rules ࢦఆͨ͠ϧʔϧͰஔ͖׵͑ͯ͘͠ΕΔ SortImports ࢦఆͨ͠৔߹: import foo.{bar, sand, Random, Zilch} ࢦఆ͠ͳ͍৔߹: import foo.{Zilch, bar, Random, sand}
12. ͋Εɾɾ
13. 4ͱ5ΛҰॹʹ(͋ͷॱ൪Ͱ) ॻ͍ͯΔͱ forࣜதͷ{}અͷalign͕ ͏·͘ػೳͯ͠ͳ͍ɾɾ
14. # See http://scalameta.org/scalafmt/#Configuration style = defaultWithAlign maxColumn = 130 includeCurlyBraceInSelectChains = false newlines.penalizeSingleSelectMultiArgList = false align = most align.tokens = [ {code = "<-"}, {code = "="}, {code = ":"}, {code = "->"}, {code = "=>"} ] align.openParenCallSite = false rewrite.rules = [ SortImports ] project.git = true project.excludeFilters = ["target/"] 4 5 →githubͷissueʹͷͬͯΔ͔΋ɻɻ align͸Ͳ͏ઃఆ͢Ε͹͍͍ͷ͔..·ͩௐ΂ͯ·ͤΜɻɻ
15. ௐ΂͍ͯͯɺ͜Ε͸ɾɾ ͙͢ೖΕ͍ͨʂͱࢥͬͨઃఆฤ • rewrite.rulesͷRedundantParens / RedundantBraces • ෆཁͳ{}, ()Λফ͠ڈͬͯ͘ΕΔ?
16. ׬ɻ