Function Currying

see also: 
http://en.wikipedia.org/wiki/Currying
http://rest-term.com/archives/2857/

by wellflat 03 Mar 2011

Talk

wellflat at 03 Mar 2011 15:36
厳密には「複数回の部分適用」です。
Embed

/**
 * Copyright wellflat ( http://wonderfl.net/user/wellflat )
 * MIT License ( http://www.opensource.org/licenses/mit-license.php )
 * Downloaded from: http://wonderfl.net/c/dh0z
 */

package {
  import flash.display.Sprite;
  import flash.text.TextField;
  
  public class FunctionCurrying extends Sprite {    
    public function FunctionCurrying() {
      var tf:TextField = new TextField();
      addChild(tf);
      var curriedSum:Function = FunctionUtils.curry(sum);
      
      var result1:int = curriedSum(1)(2,3)(4,5,6)(7,8,9,10);
      
      var result2:int = curriedSum(1)()()()()()()()()()
                                  ()(2)()()()()()()()()
                                  ()()(3)()()()()()()()
                                  ()()()(4)()()()()()()
                                  ()()()()(5)()()()()()
                                  ()()()()()(6)()()()()
                                  ()()()()()()(7)()()()
                                  ()()()()()()()(8)()()
                                  ()()()()()()()()(9)()
                                  ()()()()()()()()()(10);
                   
      tf.text = result1.toString() + ", " + result2.toString();
    }
    
    public function sum(a:int, b:int, c:int, d:int, e:int,
                        f:int, g:int, h:int, i:int, j:int):int {
      return a + b + c + d + e + f + g + h + i + j;
    } 
  }
}

  class FunctionUtils {
    // bind (== partial)
    public static function bind(f:Function, ...args):Function {
      return function(...rest):* {
        return f.apply(null, args.concat(rest));
      };
    }
    // currying
    public static function curry(f:Function, ...rest):Function {
      function currying(args:Array):* {
        if(args.length >= f.length) {
          return f.apply(null, args);
        }
        return function(...more):* {
          return currying(args.concat(more));
        };
      }
      return currying(rest);
    }
  }