Number.prototype.rand = function() {
  return Math.floor(Math.random()*this+1);
}
Number.prototype.to = function(to) {
    var array = [Number(this)];
    if (this < to) for (var i = this + 1; i <= to; ++i)    array.push(i);
    else for (var i = this - 1; i >= to; --i)    array.push(i);
    return array;
}
Number.prototype.times = function(callback) {
  if (typeof callback == 'string') callback = new Function('i', callback);
  for (var i = 0; i < this; i++) callback(i)
}

Array.prototype.map = Array.prototype.forEach = function(callback, thisObject) {
  if (typeof callback == 'string') callback = new Function('el', 'i', 'array', 'return ' + callback);
  var array = [];
  for (var i = 0, len = this.length; i < len; ++i)
    array.push(callback.call(thisObject, this[i], i, this));
  return array;
}
Array.prototype.filter = function(pred, thisObject) {
  if (typeof pred== 'string') pred= new Function('el', 'i', 'array', 'return ' + pred);
  var array = [];
  for (var i = 0, len = this.length, ret; i < len; ++i)
   if (pred.call(thisObject, this[i], i, this))
     array.push(this[i]);
  return array;
}
Array.prototype.foldRight = function(proc, seed) {
  for (var i = this.length - 1; i >= 0; --i) seed = proc.call(null, this[i], seed);
  return seed;
}
Array.prototype.deleteItem = function(item, eq, thisObject) {
  if (!eq) eq = function(x, y) { return x == y } 
    return this.remove(function(y) { return eq.call(null, item, y) }, thisObject);
}
Array.prototype.remove = function(pred, thisObject) {
  var array = [];
  for (var i = 0, len = this.length, ret; i < len; ++i)
    if (!pred.call(thisObject, this[i], i, this)) array.push(this[i]);
  return array;
}
Array.prototype.uniq = function(eq, thisObject) {
  return this.foldRight(function(item, array) { return [item].concat(array.deleteItem(item, eq, thisObject)) }, []);
}

people = 10;
days = 356;
bdays = 1 .to(people).map('days.rand()');
alert(bdays); // 151,264,286,135,17,34,266,108,135,274

collision = function(a) {
  return a.length != a.uniq().length;
}
alert(collision(bdays)); // true

collided = 0;

1000 .times("if ( collision(1 .to(people).map('days.rand()')) ) collided++");
alert(collided); // 112

alert(0 .to(1000).map("collision(1 .to(people).map('days.rand()'))")); 
// false, false, false, false, false, false, false, false, true, false, false, ...

alert(0 .to(1000).map("collision(1 .to(people).map('days.rand()'))").filter("!!el").length); // 110

alert(0 .to(1000).map("collision(1 .to(23).map('days.rand()'))").filter("!!el").length); // 499

alert(0 .to(1000).map("collision(1 .to(25).map('days.rand()'))").filter("!!el").length); // 570

Работа с данными массивов

Господа! Вопрос о рационализации.
Чтобы каждый элемент массива, допустим, обрамить тэгами <B> в языке Perl возможна следующая конструкция:

@my_arr=map("<B>$_</B>", @my_arr);

В PHP тоже есть array_map() — но ИМХО это слишком громоздко добавлять целую функцию:

function add_b($e){
  return "<B>$e</B>";
}

$my_arr=array_map("add_b", $my_arr);

Можно еще привлечь циклы, но тоже сложновато: приходится вводить две новые переменные:

foreach($my_arr as $key=>$value)
  $my_arr[$key]="<B>$value</B>"

А попроще/покрасивее никак?

function map($chunk, $sequence) {
  $output = array();
  foreach ($sequence as $_2 => $_1) 
    $output[] = eval($chunk);
  return $output;
}

$my_arr=map('return "<b>$_1</b>";', $my_arr);

send = function(msg)
{
  return {
    to: function(name){
      alert('"' + msg + '" to "' + name + '"');
    }
  }
}

send("hello").to("Pasha"); // "hello" to "Pasha"

 javascript
 functional

var data = 
  [
    [null, 'name1', ['Р.', 'Бах']],
    [null, 'name2', ['В.', 'Бах']],
    [null, 'name3', ['Л.', 'Баг']],
    [null, 'name4', ['Р.', 'Бах']],  
  ];

#	name	author
1	name1	Р. Бах
2	name2	В. Бах
3	name3	Л. Баг
4	name4	Р. Бах

bottles 0 = "no more bottles"
bottles 1 = "1 bottle"
bottles n = show n ++ " bottles"
verse 0   = "No more bottles of beer on the wall, no more bottles of beer.\n"
         ++ "Go to the store and buy some more, 99 bottles of beer on the wall."
verse n   = bottles n ++ " of beer on the wall, " ++ bottles n ++ " of beer.\n"
         ++ "Take one down and pass it around, " ++ bottles (n-1)
                                                 ++ " of beer on the wall.\n"
main      = mapM (putStrLn . verse) [99,98..0]

bottles = FunctionMaker(n);
bottles(0).eq("'no more bottles'");
bottles(1).eq("'1 bottle'");
bottles(n).eq("n + ' bottles'");

verse = FunctionMaker(n);
verse(0).eq(function(){
  return "No more bottles of beer on the wall, no more bottles of beer.\n"+
    "Go to the store and buy some more, 99 bottles of beer on the wall."
});
verse(n).eq(function(n){
  return bottles(n) + " of beer on the wall, " + bottles(n) + " of beer.\n"+
    "Take one down and pass it around, " + bottles(n-1) + 
    " of beer on the wall.\n"
});

var count = 5;
var i     = count+1;

while (--i+1) p(verse(i))

fib = FunctionMaker(n);
fib(0).eq(1);
fib(1).eq(1);
fib(n).eq("fib(n-2)+fib(n-1)");
p(fib(10));
// dump memoized value
p(fib.memo.toJSON())

89
{
 "0" : 1,
 "1" : 1,
 "2" : 2,
 "3" : 3,
 "4" : 5,
 "5" : 8,
 "6" : 13,
 "7" : 21,
 "8" : 34,
 "9" : 55,
 "10" : 89
}

• http://www.remast.de/javascript.php
  • Here are interesting links on functional JavaScript programming;
    • w3future.com — functional programming for event handlers and callback functions
    • svendtofte.com — practical (& functional) JavaScript snippets
    • svendtofte.com — great library prototype with methods for JavaScript (including map, fold, ...)
    • CodingForums — a more theoretical article on functional JavaScript by using the lambda calculus
    • Lambda tutorial — tutorial on Lambda Calculus coded in JavaScript
    • The Little JavaScripter — comparison between Scheme and JavaScript

• http://javascript.infogami.com/Functional_Javascript
• http://tokyoenvious.xrea.jp/javascript/functional/
• Use functional programming techniques to write elegant JavaScript
• Higher Order Programming - article
• http://www.svendtofte.com/
  • Practical (& functional) JavaScript snippets
  • Curried JavaScript functions

• JavaScript Closures for Dummies
• Functional Programming in JavaScript: Nice But Slow?
• http://www.kmonos.net/wlog/52.php#_0308050827 ^{китайский\японский\корейский}