Scala e JRuby

Scala e JRuby

• 1.
  Scala e JRuby União de dois mundos Maurício Eduardo Chicupo Szabo http://about.me/mauricio.szabo
• 2.
  Why? Scala World SQL é bom! Paralelismo, actors… Linguagens devem ser estáticas! Ruby World ORMs são bons! Fibers, workers, redis... Linguagens dinâmicas são melhores!
• 3.
  Why? Because WeCAN!
• 4.
  How? ● Rubyroda na JVM - JRuby. ● Sintaxes semelhantes
• 5.
  Sintaxes numbers =(1..20).map { |e| e * 2 } h = numbers.each_with_index .inject({}) do |hash, (number, index)| hash.merge(index => number) end val numbers = 1 to 20 map { e => e * 2 } val m = numbers.zipWithIndex .foldLeft(Map[Int, Int]()) { case(map, (number, index)) => map + (index -> number) }
• 6.
  But HOW? ●org.jruby.Ruby ← Environment ● Ruby#evalScriptlet ● IRubyObject ● IRubyObject#callMethod Ruby("puts 'Hello, world!'")
• 7.
  Scala Way ●AbstractRubyWrapper ● trait Ruby[A <: AbstractRubyWrapper] ● __toRubyWrapper val r = Ruby("'some string'") r: RubyImpl = "some string" r.upcase res0: RubyImpl = "SOME STRING"
• 8.
  Scala Way ●init ● normalize ← params enviados para JRuby val bd = Ruby(‘"BigDecimal").init("2.05") bd: ruby.RubyImpl = #<BigDecimal: 58b0dd88,'0.205E1',3(4)> (bd + 20).to_f res0: ruby.RubyImpl = 22.05
• 9.
  Scala Conversions ●Estático → Dinâmico → Estático → Dinâmico ● null → nil (NilClass) → ……..? (bd + Ruby("20")).to_f res0: ruby.RubyImpl = 22.05
• 10.
  Estático / Dinâmico ● Conversões de dinâmico para estático ● rubyResult.as(String) ● rubyResult.any val m = Ruby("{:ten => 10, :twenty => 20}").as(Map) m: Map[Any,Any] = Map('twenty -> 20, 'ten -> 10) val d = Ruby("10").as(Int) d: Int = 10
• 11.
  Scala Conversions ●Objects → Boolean if(Ruby("nil")) 10 else 20 res0: Int = 20 if(Ruby("10")) 10 else 20 res1: Int = 10 if(Ruby("0")) 10 else 20 res2: Int = 10
• 12.
  Scala Conversions ●Funções → Proc → Funções val h = Ruby("Hash").init { (_: Any, e: String) => e.toUpperCase } h: ruby.RubyImpl = {} h("Some String") res0: ruby.RubyImpl = "SOME STRING" h(10) java.lang.ClassCastException: java.lang.Long cannot be cast to java.lang.String
• 13.
  Nulo... ● Rubynil é uma classe, Scala null é… bem… ● val a: String = null ● rubyObject.as[String] // => Option[String] val s = Ruby("'Hello, world!'").as[String] s: Option[String] = Some(Hello, world!) val s = Ruby("nil").as[String] s: Option[String] = None
• 14.
  Casts de Generics ● Cast de Listas ● Cast de Mapas val list = Ruby("[1, 2, 3]").as[List, Int] list: Option[List[Int]] = Some(Vector(1, 2, 3)) val map = Ruby("{:ten => 10}").asMap[Symbol, Int] map: Option[Map[Symbol,Int]] = Some(Map('ten -> 10)) val vector = Ruby("[1, 2, 3]").as[Vector, Int] vector: Option[Vector[Int]] = Some(Vector(1, 2, 3))
• 15.
  Subclassing ● SimpleSubclass ● Override ● (alguns problemas com classe… ainda) class Skate extends SimpleSubclass("Vehicles"){ def max_speed = 45 }
• 16.
  ActiveRecord ● activerecord.Model object Person extends active_record.Model { scope('foo, this.where('name -> "Foo")) scope('age, a => this.where('age -> a)) this has_many 'children } Person.where('name -> "Foo").where('age ->) Person.foo.age(17).limit(20)
• 17.
  Sinatra ● Notthere yet... class SinatraApp extends SubclassOf(SinatraApp) object SinatraApp extends Subclass[SinatraApp]("Sinatra::Base") { this.reset_! this.get("/", { () => "Hello, world!" }) }
• 18.
  But... WHY????
• 19.
  Mais informações https://github.com/mauricioszabo/Ruby2Scala http://jruby.org/apidocs/