スタイルガイドを整備しても
“any style guide written in English is
either so brief that it’s ambiguous, or so
long that no one reads it.”
Bob Nystrom
The Hardest Program I've Ever Written
http://journal.stuffwithstuff.com/2015/09/08/the-hardest-program-ive-ever-written/
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エディタの設定を共有する？
人によって使っているエディタや
IDEは違う！
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Code Formatter!!
“Spend more time discussing important
issues in code review and less time on
code style. Scalafmt formats code so that
it looks consistent between people on
your team.”
scalafmt.org
maxColumn (default: 80)
// before
class ExtendTest extends A with B with C with D
// after (maxCoulumn=20)
class ExtendTest
extends A
with B
with C
with D
※必ず指定した値以内に収まるわけではないことに注意
continuationIndent.callSite (default: 2)
// before
function(
foo: Type,
bar: Type
)
// after
function(
foo: Type,
bar: Type
)
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continuationIndent.defnSite (default: 4)
// before
def function(
foo: Type,
bar: Type
)
// after
def function(
foo: Type,
bar: Type
)
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continuationIndent.extendSite (default: 4)
// before
class UserProfile
extends Profile
with SomeTrait
// after
class UserProfile
extends Profile
with SomeTrait
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align
「=」「<-」「%%」「//」などを縦方向で揃える設定
- none
- some (default)
- more
- most
align.tokens で詳細を設定できるが、上記の4種類で十分
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align = none
// before
x match {
case "foo" => 1 // comment
case "hoge" => 123 // comment
case "foobar" => 12345 // comment
}
// after
x match {
case "foo" => 1 // comment
case "hoge" => 123 // comment
case "foobar" => 12345 // comment
}
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align = some (default)
// before
x match {
case "foo" => 1 // comment
case "hoge" => 123 // comment
case "foobar" => 12345 // comment
}
// after (case match の => のみ align する)
x match {
case "foo" => 1 // comment
case "hoge" => 123 // comment
case "foobar" => 12345 // comment
}
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align = more
// before
x match {
case "foo" => 1 -> 1 // comment
case "hoge" => 123 -> 123 // comment
case "foobar" => 12345 -> 12345 // comment
}
// after (// や -> も)
x match {
case "foo" => 1 -> 1 // comment
case "hoge" => 123 -> 123 // comment
case "foobar" => 12345 -> 12345 // comment
}
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align = more
// before
val foo = 1
val hoge = 2
libraryDependencies ++= Seq(
"org.scala-lang" % "scala-compiler" % scalaVersion.value,
"com.tanishiking" %% "scalaunfmt" % "0.0.1"
)
// after (= や sbtの % も)
val foo = 1
val hoge = 2
libraryDependencies ++= Seq(
"org.scala-lang" % "scala-compiler" % scalaVersion.value,
"com.tanishiking" %% "scalaunfmt" % "0.0.1"
)
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align = most
// before
for {
x <- List()
yyy = 2
} yield {
// ...
}
// after (<- と = をもalign)
for {
x <- List()
yyy = 2
} yield {
// ...
}
RewriteRules - AvoidInfix
// before
foo toList map { x =>
x should have length 5
}
// after
foo.toList.map { x =>
(x should have).length(5)
}
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RewriteRules - RedundantBraces
// before
val x: Int => String = {
case 2 => { "two" }
case _ => { "other" }
}
// after
val x: Int => String = {
case 2 => "two"
case _ => "other"
}
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RewriteRules - RedundantParens
// before
for {
a <- b
if ((b ++ b).length >= 2)
} yield a
// after
for {
a <- b
if (b ++ b).length >= 2
} yield a
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RewriteRules - SortModifiers
// before
final lazy private implicit val x = 42
lazy final implicit private val y = 42
// after
implicit final private lazy val x = 42
implicit final private lazy val y = 42
sortModifiers.order = [“implicit”, “final” … ] で順番の設定も可能
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RewriteRules - SortImports
// before
import a.b.{c, a, b}, k.{
g, f
}
// after
import a.b.{a, b, c}, k.{f, g}