1. 2014.6.25 Functional (@maeda_) Scala

2. ( twitter : @maeda_ ) ( http://www.illi-ichi.com ) 3. Scala Scala 4. Scala = 5. Scala 6. Scala 1. Java 2. ML Scala case class case object object class HaskellML ML Modules and Haskell Type Classes: A Constructive Comparison http://www.cse.unsw.edu.au/~chak/papers/modules-classes.pdf 7. Scala 1. Java 2. ML Scala case class case object object class HaskellML ML Modules and Haskell Type Classes: A Constructive Comparison http://www.cse.unsw.edu.au/~chak/papers/modules-classes.pdf 8. / 9. object (= ) objectHoge{ deffoo(...)=... } Hoge.foo(...)//Hogefoo classHogeClass(){ deffoo(...)=... } valHoge=newHogeClass() 10. classHoge(connectionString:String){ deffoo(...)=... } // valhoge=newHoge("jdbc:h2:mem:test") hoge.foo(...) 11. packageimport classHoge(fuga:Fuga){ importfuga._ ... } Scalaimport 12. Javastatic //private classHogeprivate(...){...} objectHoge{ //Hoge deffromString(str:String):Hoge=newHoge(...) deffromFile(file:File):Hoge=newHoge(...) } REPL:paste 13. 14. valmenu:Map[String,Action]=Map( "hungry"->GoTo("restaurant"), "tired"->Sleep, ... ) Parser.parse("")//NoInput Parser.parse("hun")//Entering(GoTo("restaurant"),3) Parser.parse("hunt")//WrongInput Parser.parse("hungry")//Completed(GoTo("restaurant")) 15. objectParser{ sealedabstractclassAction caseclassGoTo(place:String)extendsAction caseobjectSleepextendsAction sealedabstractclassState caseobjectNoInputextendsState caseclassEntering(action:Action,count:Int)extendsState caseclassCompleted(action:Action)extendsState caseobjectWrongInputextendsState valmenu:Map[String,Action]= Map("hungry"->GoTo("restaurant"),"tired"->Sleep,...) defparse(Stringinput):State=... defmaxMenuLength:Int=... } Parser.parse("hun")//Parser.Entering(Parser.GoTo("restaurant"),3) Parser.parse("hunt")//Parser.WrongInput #1 object 16. objectParser{ sealedabstractclassAction caseclassGoTo(place:String)extendsAction caseobjectSleepextendsAction sealedabstractclassState caseobjectNoInputextendsState caseclassEntering(action:Action,count:Int)extendsState caseclassCompleted(action:Action)extendsState caseobjectWrongInputextendsState valmenu:Map[String,Action]= Map("hungry"->GoTo("restaurant"),"tired"->Sleep,...) defparse(Stringinput):State=... defmaxMenuLength:Int=... } Parser.parse("hun")//Parser.Entering(Parser.GoTo("restaurant"),3) Parser.parse("hunt")//Parser.WrongInput Parser Parser #1 object 17. objectParser{ sealedabstractclassAction caseclassGoTo(place:String)extendsAction caseobjectSleepextendsAction sealedabstractclassState caseobjectNoInputextendsState caseclassEntering(action:Action,count:Int)extendsState caseclassCompleted(action:Action)extendsState caseobjectWrongInputextendsState valmenu:Map[String,Action]= Map("hungry"->GoTo("restaurant"),"tired"->Sleep,...) defparse(Stringinput):State=... defmaxMenuLength:Int=... } Parser.parse("hun")//Parser.Entering(Parser.GoTo("restaurant"),3) Parser.parse("hunt")//Parser.WrongInput #1 object 18. objectParser{ sealedabstractclassAction caseclassGoTo(place:String)extendsAction caseobjectSleepextendsAction sealedabstractclassState caseobjectNoInputextendsState caseclassEntering(action:Action,count:Int)extendsState caseclassCompleted(action:Action)extendsState caseobjectWrongInputextendsState valmenu:Map[String,Action]= Map("hungry"->GoTo("restaurant"),"tired"->Sleep,...) defparse(Stringinput):State=... defmaxMenuLength:Int=... } Parser.parse("hun")//Parser.Entering(Parser.GoTo("restaurant"),3) Parser.parse("hunt")//Parser.WrongInput #1 object 19. objectParser{ sealedabstractclassAction caseclassGoTo(place:String)extendsAction caseobjectSleepextendsAction sealedabstractclassState caseobjectNoInputextendsState caseclassEntering(action:Action,count:Int)extendsState caseclassCompleted(action:Action)extendsState caseobjectWrongInputextendsState valmenu:Map[String,Action]= Map("hungry"->GoTo("restaurant"),"tired"->Sleep,...) defparse(Stringinput):State=... defmaxMenuLength:Int=... } Parser.parse("hun")//Parser.Entering(Parser.GoTo("restaurant"),3) Parser.parse("hunt")//Parser.WrongInput #1 object 20. sealedabstractclassAction caseclassGoTo(place:String)extendsAction caseobjectSleepextendsAction classParser(menu:Map[String,Action]){ sealedabstractclassState caseobjectNoInputextendsState caseclassEntering(action:Action,count:Int)extendsState caseclassCompleted(action:Action)extendsState caseobjectWrongInputextendsState defparse(Stringinput):State=... defmaxMenuLength:Int=... } valparser=newParser( Map("hungry"->GoTo("restaurant"),"tired"->Sleep,...)) parser.parse("hun")//parser.Entering(GoTo("restaurant"),3) parser.parse("hunt")//parser.WrongInput #2 21. sealedabstractclassAction caseclassGoTo(place:String)extendsAction caseobjectSleepextendsAction classParser(menu:Map[String,Action]){ sealedabstractclassState caseobjectNoInputextendsState caseclassEntering(action:Action,count:Int)extendsState caseclassCompleted(action:Action)extendsState caseobjectWrongInputextendsState defparse(Stringinput):State=... defmaxMenuLength:Int=... } valparser=newParser( Map("hungry"->GoTo("restaurant"),"tired"->Sleep,...)) parser.parse("hun")//parser.Entering(GoTo("restaurant"),3) parser.parse("hunt")//parser.WrongInput #2 class 22. sealedabstractclassAction caseclassGoTo(place:String)extendsAction caseobjectSleepextendsAction classParser(menu:Map[String,Action]){ sealedabstractclassState caseobjectNoInputextendsState caseclassEntering(action:Action,count:Int)extendsState caseclassCompleted(action:Action)extendsState caseobjectWrongInputextendsState defparse(Stringinput):State=... defmaxMenuLength:Int=... } valparser=newParser( Map("hungry"->GoTo("restaurant"),"tired"->Sleep,...)) parser.parse("hun")//parser.Entering(GoTo("restaurant"),3) parser.parse("hunt")//parser.WrongInput #2 Action Parser 23. sealedabstractclassAction caseclassGoTo(place:String)extendsAction caseobjectSleepextendsAction classParser[A](menu:Map[String,A]){ sealedabstractclassState caseobjectNoInputextendsState caseclassEntering(action:A,count:Int)extendsState caseclassCompleted(action:A)extendsState caseobjectWrongInputextendsState defparse(Stringinput):State=... defmaxMenuLength:Int=... } valparser:Parser[Action]=newParser( Map("hungry"->GoTo("restaurant"),"tired"->Sleep,...)) parser.parse("hun")//parser.Entering(GoTo("restaurant"),3) parser.parse("hunt")//parser.WrongInput #3 24. sealedabstractclassAction caseclassGoTo(place:String)extendsAction caseobjectSleepextendsAction classParser[A](menu:Map[String,A]){ sealedabstractclassState caseobjectNoInputextendsState caseclassEntering(action:A,count:Int)extendsState caseclassCompleted(action:A)extendsState caseobjectWrongInputextendsState defparse(Stringinput):State=... defmaxMenuLength:Int=... } valparser:Parser[Action]=newParser( Map("hungry"->GoTo("restaurant"),"tired"->Sleep,...)) parser.parse("hun")//parser.Entering(GoTo("restaurant"),3) parser.parse("hunt")//parser.WrongInput #3 Parser 25. abstractclassParser{ typeA defmenu:Map[String,A] sealedabstractclassState caseobjectNoInputextendsState caseclassEntering(action:A,count:Int)extendsState caseclassCompleted(action:A)extendsState caseobjectWrongInputextendsState defparse(Stringinput):State=... defmaxMenuLength:Int=... } sealedabstractclassAction caseclassGoTo(place:String)extendsAction caseobjectSleepextendsAction valparser:Parser=newParser{ typeA=Action valmenu=Map("hungry"->GoTo("restaurant"), "tired"->Sleep,...) } parser.parse("hun")//parser.Entering(GoTo(Restaurant),3) parser.parse("hunt")//parser.WrongInput #4 26. abstractclassParser{ typeA defmenu:Map[String,A] sealedabstractclassState caseobjectNoInputextendsState caseclassEntering(action:A,count:Int)extendsState caseclassCompleted(action:A)extendsState caseobjectWrongInputextendsState defparse(Stringinput):State=... defmaxMenuLength:Int=... } sealedabstractclassAction caseclassGoTo(place:String)extendsAction caseobjectSleepextendsAction valparser:Parser=newParser{ typeA=Action valmenu=Map("hungry"->GoTo("restaurant"), "tired"->Sleep,...) } parser.parse("hun")//parser.Entering(GoTo(Restaurant),3) parser.parse("hunt")//parser.WrongInput #4 27. abstractclassParser{ typeA defmenu:Map[String,A] sealedabstractclassState caseobjectNoInputextendsState caseclassEntering(action:A,count:Int)extendsState caseclassCompleted(action:A)extendsState caseobjectWrongInputextendsState defparse(Stringinput):State=... defmaxMenuLength:Int=... } sealedabstractclassAction caseclassGoTo(place:String)extendsAction caseobjectSleepextendsAction valparser:Parser=newParser{ typeA=Action valmenu=Map("hungry"->GoTo("restaurant"), "tired"->Sleep,...) } parser.parse("hun")//parser.Entering(GoTo(Restaurant),3) parser.parse("hunt")//parser.WrongInput #4 28. abstractclassParser{ typeAction defmenu:Map[String,Action] sealedabstractclassState caseobjectNoInputextendsState caseclassEntering(action:Action,count:Int)extendsState caseclassCompleted(action:Action)extendsState caseobjectWrongInputextendsState defparse(Stringinput):State=... defmaxMenuLength:Int=... } valparser:Parser=newParser{ sealedabstractclassAction caseclassGoTo(place:String)extendsAction caseobjectSleepextendsAction valmenu=Map("hungry"->GoTo("restaurant"), "tired"->Sleep,...) } parser.parse("hun")//parser.Entering(GoTo(Restaurant),3) parser.parse("hunt")//parser.WrongInput #5Action 29. abstractclassParser{ typeAction defmenu:Map[String,Action] sealedabstractclassState caseobjectNoInputextendsState caseclassEntering(action:Action,count:Int)extendsState caseclassCompleted(action:Action)extendsState caseobjectWrongInputextendsState defparse(Stringinput):State=... defmaxMenuLength:Int=... } valparser:Parser=newParser{ sealedabstractclassAction caseclassGoTo(place:String)extendsAction caseobjectSleepextendsAction valmenu=Map("hungry"->GoTo("restaurant"), "tired"->Sleep,...) } parser.parse("hun")//parser.Entering(GoTo(Restaurant),3) parser.parse("hunt")//parser.WrongInput #5Action 30. abstractclassParser{ typeAction defmenu:Map[String,Action] sealedabstractclassState caseobjectNoInputextendsState caseclassEntering(action:Action,count:Int)extendsState caseclassCompleted(action:Action)extendsState caseobjectWrongInputextendsState defparse(Stringinput):State=... defmaxMenuLength:Int=... } objectSomeParserextendsParser{ sealedabstractclassAction caseclassGoTo(place:String)extendsAction caseobjectSleepextendsAction valmenu=Map("hungry"->GoTo("restaurant"),"tired"->Sleep,...) } SomeParser.parse("hun")//SomeParser.Entering(GoTo("restaurant"),3) SomeParser.parse("hunt")//SomeParser.WrongInput #6 object 31. JavaInner Class valsomeParser=newParser(...) valantotherParser=newParser(...) someParser.parse(...)//someParser.During(...) anotherParser.parse(...)//anotherParser.During(...) // valstate:someParser.State=anotherParser.parse(...) 32. Scala () ScalaML... in OCaml 33. Scala A () A () abstractclassKlass{ typeA defshow:A=>String } abstractclassKlass[A]{ defshow:A=>String } Scala(forSome) forSome 34. 35. ... // classParser[A](menu:Map[String,A]){ defparse(input:String):State[A]=... } // defparse[A](menu:Map[String,A])(input:String):State[A]=... valparser:String=>State[Action]=parse(Map(...)) 36. 2 ML // classParser[A](menu:Map[String,A]){ defparse(input:String):State[A]=... defmaxMenuLength:Int=... } // typeParser[A]={ defparse(input:String):State[A] defmaxMenuLength:Int } defcreateParser[A](menu:Map[String,A]):Parser=... 37. ML OCaml Scala Java 38. ... ( ) (RCATWD) http://www.infoq.com/jp/news/2010/07/objects-smalltalk-erlang 39. trait 40. trait trait objectHoge{ } traitSomePart{ } traitAnotherPart{ } //trait(mix-in) objectHogeextendsSomePart withAnotherPart Some Functions Another Functions Some Functions Another Functions 41. mix-in //object objectHogeextendsSomePartwithAnotherPart //mix-in valhoge=newSomePartwithAnotherPart valfuga=newSomePartwithYetAnotherPart //mix-in valfoo=if(config.availableXXX)newSomePartwithXXX elsenewSomePartwithDefault 42. (self type) traittrait objectHoge{ } traitSomePart{ } traitAnotherPart{this:SomePart=> } objectHogeextendsSomePart withAnotherPart Some Functions Another Functions Some Functions Another Functions Call mix-in SomePart 43. trait trait mix-in traitHogeSignature{// deffunc(arg:Int):String } traitFuga{this:HogeSignature=>// ... } traitHogeextendsHogeSignature{// deffunc(arg:Int):String=... } objectSomeModuleextendsFugawithHoge// 44. MLsignature ML structure(struct) signature(sig) traitMLsignature (*OCamlREPL*) # module Three = struct let x = 3 end;; module Three : sig val x : int end # module type X_int = sig val x : int end;; module type X_int = sig val x : int end # module Increment (M : X_int) = struct let x = M.x + 1 end;; module Increment : functor (M : X_int) -> sig val x : int end Real World OcamlChapter 9 Functor 45. trait DSL //ScalaTest //ShouldMatchermix-in... classHogeSpecextendsSpecificationwithShouldMatcher{ //should "hoge"in{ hogeshouldequal(3) } //Akka(Actor) //ActorLoggingmix-in... classHogeActorextendsActorwithActorLogging{ // defreceive={... 46. 47. Scala 48. pure State valhoge=newHoge(bufferSize=100)// valresult1=hoge.heavyCalc(10) valresult2=hoge.heavyCalc(10) valcache=Cache.empty(bufferSize=100) val(result1,cache1)=Hoge.heavyCalc(10,cache) val(result2,cache2)=Hoge.heavyCalc(10,cache1) 49. override overrideStackable Trait () http://www.artima.com/scalazine/articles/stackable_trait_pattern.html ""in{ valstub=newSomeStub{overridedefhoge(...)=...} ... } ""in{ valstub=newSomeStub{overridedeffuga(...)=...} ... } traitHogewithFuga{ abstractoverridedeffoo(x:X)=super.foo(modify(x)) ... 50. case object sealedabstractclassErrorReason(valerrorCode:String) caseobjectInvalidInputextendsErrorReason("E001") caseobjectNotAuthorizedextendsErrorReason("E002") ... 51. Scala Scala