Ruby vs Scala_Ruby_编程开发_程序员俱乐部

1. no ; at the end of lines

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2. base operate

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scala:
? val list = Array(1,2,3,4) ?
??
? list.filter( _ % 2 == 0)
? list.filter{e: Int => (e % 2 == 0)}
ruby:

? list = [1,2,3,4]
? list.select{|x| x % 2 == 0}

3. staic types

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scala:
? ?import scala.collection.mutable.HashMap
? ?var hash =new HashMap[Int, String]
? ?hash += (1 -> "hello")
? ?hash += (3) #error: type mismatch;?

ruby:?
? ?hash = Hash.new
? ?hash = 3 #3

4. Dynamic calls

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scala:
import scala.language.dynamics

class Animal extends Dynamic {
?def selectDynamic(name: String) {
? ?println("Animal wants to " + name)
?}

?def applyDynamic(name: String)(args: Any*) {
? ?println("Animal wants to " + name + args.mkString(","))
?}
}

scala> var a = new Animal
scala> a.say
Animal wants to say
scala> a.say("hello")
Animal wants to say hello

ruby:?
class Animal
?def method_missing name,*args
? ?if args.empty?
? ? ?puts "Animal says " + name.to_s
? ?else
? ? ?puts "Animal wants to " + name.to_s + args.join(",")
? ?end
? ?self
?end
end

2.2.1 :020 > animal = Animal.new
2.2.1 :020 > animal.qualk
Animal says qualk
2.2.1 :021 > animal.say("hello")
Animal wants to say hello

5. minxin

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scala:
trait MyClass {
?def my_method = println("my method")
}
class IncludeTrait extends MyClass
scala> (new IncludeTrait).my_method
my method

ruby:?
module MyModule
?def my_method
? ?puts "my_method"
?end
end

class IncludeModule
?include MyModule
end

2.2.1 :032 >IncludeModule.new.my_method
my_method

6.duck type

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scala:
class Duck{
?def quack = { println("duck quack..")}
?def walk = { println("duck walk..")}
}


class Platypus{
?def quack = { println("platypus quack..")}
?def walk = { println("platypus walk..")}
}

def ActAsADuck(a: {def quack; def walk}) = {
?a.quack
?a.walk
}

val duck ?= new Duck
val paltypus = new Platypus
ActAsADuck(duck)
ActAsADuck(platypus)


ruby:
class Duck
?def quack; end
?def walk; end
end

class Platypus
?def quack; end
?def walk; end
end

def act_as_a_duck(animal)
?animal.quack
?animal.walk
end

duck = Duck.new
platypus = Platypus.new

act_as_a_duck(duck)
act_as_a_duck(platypus)

7. unit test

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scala:?

@Test def myTest(){
?val array = List(1,2,3)
?assert(array(0) === 1)
}

ruby:?

test "my test" do?
?array = [1,2,3]
?assert_equal 1, array.first
end

8. spec test

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scala:

describe("Get of List"){
?it("(0) returns the first element") ?{
? ?val array = List(1,2,3)
? ?array(0) should be 1
?}
}

ruby :
describe "Get of Array" do?
it "first returns the first element" do?
? array = [1,2,3]
? array.first.should == 1
?end
end

9. web platform

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scala:

Play是一个开源高性能Web框架，能够基于Java或Scala编写可扩展可伸缩的应用系统，它能自动刷新源码的变动从而具有快速开发产品的能力，它还是一个无态非堵塞的框架，易于横向扩展。Play!框架有如下特点：高开发效率：Java EE和Spring框架并不适合快速原型开发，Play框架参考动态语言的快速开发能力，它支持热重载所有的Java代码和模板等，让你更快地迭代。基于Netty构建非堵塞异步机制。RESTJSON支持：非常容易编写RESTful应用，非常适合支持HTTP路由。

Akka是一个用Scala编写的库，用于简化编写容错的、高可伸缩性的Java和Scala的Actor模型应用。它已经成功运用在电信行业。系统几乎不会宕机（高可用性99.9999999%一年只有31ms宕机

ruby:?
Ruby on Rails是一个用于开发数据库驱动的网络应用程序的完整框架。Rails基于MVC设计模式。从视图中的Ajax应用，到控制器中的访问请求和反馈，到封装数据库的模型，Rails为你提供一个纯Ruby的开发环境。发布网站时，你只需要一个数据库和一个网络服务器即可。

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10. performance

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