yuroyoro’s gists

Created December 16, 2010 06:42

	scala> def Y[A,B](f:((A => B),A) => B,x:A):B = f((y:A) =>Y(f,y),x)
	Y: [A,B](f: ((A) => B, A) => B,x: A)B

	scala> Y((f:Int => String,n:Int) => n match{case 0 => "ば";case 20 => "あ" + f(n-1);case m =>"ば" + f(n-1);},20)
	res32: java.lang.String = あばばばばばばばばばばばばばばばばばばばば

yuroyoro / Yコンビネータであばばば(ワンライナ—版).scala

Created December 16, 2010 09:05

	scala> Option({ def Y[Int,String](f:((Int => String),Int) => String,x:Int):String = f((y:Int) =>Y(f,y),x);Y( _:((Int => String),Int) => String,_:Int)}).map{y => y((f:Int => String,n:Int) => n match{case 0 => "ば";case 20 => "あ" + f(n-1);case m =>"ば" + f(n-1);},20)}.get
	res42: String = あばばばばばばばばばばばばばばばばばばばば

yuroyoro / gist:766020

Created January 5, 2011 07:18

	scala> class Foo[A](v:A)(implicit val mf:Manifest[A]){
	\| def typeParam = mf.erasure
	\| }
	defined class Foo

	scala> (new Foo(99)).typeParam
	res2: java.lang.Class[_] = int

	scala> (new Foo("HOGE")).typeParam
	res3: java.lang.Class[_] = class java.lang.String

yuroyoro / GenericsTrick.java

Created January 20, 2011 07:09

型パラメータTのインスタンスを無理矢理(ヤメテーッッ)生成する方法

	public class GenericsTrick {

	public static void main(String[] args){
	try{
	System.out.println(
	(new GenericsTrick()).createInstance(new Foo[]{})
	);
	}catch(Throwable e){
	e.printStackTrace();
	}

yuroyoro / FizzBuzz

Created January 24, 2011 07:40

yuroyoro / Main$.jad

Created March 17, 2011 07:25

scalaのlazy valってこんな風に初期化されるんですぜ(2.9)

	// Decompiled by Jad v1.5.8g. Copyright 2001 Pavel Kouznetsov.
	// Jad home page: http://www.kpdus.com/jad.html
	// Decompiler options: packimports(3)
	// Source File Name: Main.scala

	import scala.Predef$;
	import scala.ScalaObject;
	import scala.collection.immutable.StringLike;
	import scala.runtime.BoxedUnit;
	import scala.util.Random$;

yuroyoro / Nuclear.scala

Created March 17, 2011 08:08

Scalaのlazy valを強制的に再評価する(2.9)

	class Nuclear{
	lazy val radioactivity = {
	println( "%sμSv/hだって " format util.Random.nextFloat * 400f)
	"(((((((( ；ﾟДﾟ))))))))ｶﾞｸｶﾞｸﾌﾞﾙﾌﾞﾙｶﾞﾀｶﾞﾀﾌﾞﾙﾌﾞﾙ "* util.Random.nextInt(4)
	}
	}

yuroyoro / DynamicTest.scala

Created March 26, 2011 06:51

scala2.9.0.RC1でのDynamicのテスト

	[0]ozaki@mbp $ scala -Xexperimental [~/sandbox/scala/work][0]
	Picked up _JAVA_OPTIONS: -Dfile.encoding=UTF-8
	Welcome to Scala version 2.9.0.RC1 (Java HotSpot(TM) 64-Bit Server VM, Java 1.6.0_22).
	Type in expressions to have them evaluated.
	Type :help for more information.

	scala> trait DI extends Dynamic {
	\| def applyDynamic(name:String)(args:Any*):Any = println("Hello, %s %s" format( name, args.mkString("[", ", ", "]")))
	\| }
	defined trait DI

yuroyoro / Main.scala

Created April 18, 2011 06:52

Scalaの無限リスト(Stream)でいろいろと

	// 初期値とstepを指定して永遠にカウントするItrator
	class Counter[T:Numeric](init:T = 0,step:T = 1) extends Iterator[T] {
	var cnt = init
	def hasNext = true
	def next = {
	cnt = implicitly[Numeric[T]].plus(cnt, step)
	cnt
	}
	// 自分をStreamにする
	def asStream = Stream.continually( next )

yuroyoro / ComposableFunction1.scala

Created April 28, 2011 04:33

Scalaでも>>とか<<で関数合成できるように。

	scala> trait ComposableFunction1[-T1, +R] {
	\| val f: T1 => R
	\| def >>[A](g:R => A):T1 => A = f andThen g
	\| def <<[A](g:A => T1):A => R = f compose g
	\| }
	defined trait ComposableFunction1

	scala> implicit def toComposableFunction1[T1,R](func:T1 => R) = new ComposableFunction1[T1,R]{ val f = func }
	toComposableFunction1: [T1,R](func: (T1) => R)java.lang.Object with ComposableFunction1[T1,R]

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