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「純粋関数型JavaScriptのつくりかた」に触発されて

Last updated at Posted at 2019-06-03

「純粋関数型JavaScriptのつくりかた」の記事に

あなたの好きな言語を浄化して
純粋関数型プログラミング言語にすることができます。

とありました。
やってみました。

C#
using System;
class Pure{

  public static
  Func<object,Func<object>>
  pure=a=>()=>a;

  public static
  Func<Func<object>,
  Func<Func<object,Func<object>>,
  Func<object>>>
  bind=m=>f=>()=>f(m())();

  public static
  Func<Func<object>,object>
  exec=m=>m();

  public static
  Func<Func<object,object>,
  Func<object,Func<object>>>
  wrap=f=>a=>()=>f(a);
}

class MainClass{
  static void Main(){

    Func<object,Func<object>>
    put=Pure.wrap(a=>
    {Console.WriteLine(
    ((string)a).ToUpper());
    return a;});

    Func<object,Func<object>>
    get=Pure.wrap(x=>
    Console.ReadLine());

    Func<object>
    main=Pure.bind(get(null))(put);
   
    Pure.exec(main);
  }
}
Java
import java.io.*;
import java.util.function.*;

class Pure{

  public static
  Function<Object,Supplier<Object>>
  pure=a->()->a;

  public static
  Function<Supplier<Object>,
  Function<Function<Object,
  Supplier<Object>>,
  Supplier<Object>>>
  bind=m->f->
  ()->f.apply(m.get()).get();

  public static
  Function<Supplier<Object>,Object>
  exec=m->m.get();

  public static
  Function<Function<Object,Object>,
  Function<Object,
  Supplier<Object>>>
  wrap=f->a->()->f.apply(a);
}

class Main{
  
  static BufferedReader in=new
  BufferedReader(new
  InputStreamReader(System.in));

  static Object _get(){
    Object s=null;
    try{
      s=in.readLine();
    }catch(Exception e){
      e.printStackTrace();
    }
    return s;
  }

  public static void 
  main(String[]args){
    
    Function<Object,
    Supplier<Object>>
    put=Pure.wrap.apply(a->
    {System.out.println(
    ((String)a).toUpperCase());
    return a;});

    Function<Object,
    Supplier<Object>>
    get=Pure.wrap.apply(x->_get());
     
    Supplier<Object>
    main=Pure.bind.apply(
    get.apply(null)).apply(put);
   
    Pure.exec.apply(main);
  }
}
Python3
#pure=a=>()=>a;
pure=lambda a:lambda:a

#bind=m=>f=>()=>f(m())();
bind=lambda m:lambda f:lambda:f(m())()

#exec=m=>m();
exec=lambda m:m()

#wrap=f=>a=>()=>f(a);
wrap=lambda f:lambda a:lambda:f(a)

put=wrap(lambda a:print(a.upper()))

get=wrap(lambda x:input())

main=bind(get(""))(put)

exec(main)
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