狠狠撸

Почему
функциональное
программирование?
Сборная солянка

def sum(list):
result = 0
for element in list:
result = result + element
return result

sum' [] = 0
sum' (x:xs) = x + sum' xs

public static <E extends Comparable<? super E>> List<E> quickSort(List<E> arr) {
if (arr.size() <= 1)
return arr;
E pivot = arr.getFirst();

List<E> less = new LinkedList<E>();
List<E> pivotList = new LinkedList<E>();
List<E> more = new LinkedList<E>();

for (E i: arr) {
if (i.compareTo(pivot) < 0)
less.add(i);
else if (i.compareTo(pivot) > 0)
more.add(i);
else
pivotList.add(i);
}

less = quickSort(less);
more = quickSort(more);

less.addAll(pivotList);
less.addAll(more);
return less;
}

def qsort[T <% Ordered[T]](list:List[T]):List[T] = {
list match {
case Nil => Nil
case x::xs =>
val (before,after) = xs partition (_ < x)
qsort(before) ++ (x :: qsort(after))
}
}

sum(L) ->
lists:foldl(fun(X, Sum) -> X + Sum end, 0, L).

Параллелизм
Программа выполняется
быстрее в условиях
многоядерного окружения

Конкурентность
Неизбежное
взаимодействие
конкурентных потоков в
предметной области

var x = 0;

setTimeout(function () { x = x + 1; }, 0);
setTimeout(function () { x = x * 2; }, 0);

console.log(x);

$people = array();
$men = array();
$women = array();

foreach ($people as $person) {
array_push(($person->gender == 'male' ? $men : $women), $person)
}

val people: Array[Person]
val (men, women) = people partition (_.gender == "male")

???
val (men, women) = people.par partition (_.gender == "male")

???
val totalMoney = people.par map (_.money) reduce (_+_)

actor {
receive {
case people: Set[Person] =>
val (men, women) = people partition (_.gender == "male")
Cosmopolitan ! women
Playboy ! men
}
}

class OrderController < ApplicationController
before_filter :authenticate_user!
before_filter :load_order, only: [:edit, :update, :destroy]
before_filter :create_order_from_params, only: [:new, :create]
before_filter :authorize_user_on_order!, only: [:edit, :update, :destroy]
before_filter :update_order_from_params, only: [:update]
before_filter :render_if_save_error, only: [:create, :update]

def new; end
def edit; end

def create
redirect_to success_url
end

def update
redirect_to @order
end

def destroy
@order.destroy
redirect_to success_url
end

def load_order
@order = Order.find params[:id]
end

def create_order_from_params
@order = Order.new params[:order]
end

def authorize_user_on_order!
permission_denied! unless current_user.can_edit? @order
end

def update_order_from_params
@order.update_attributes
end

def render_if_save_error
unless @order.valid?
render 'error' and return false
end
end


def new
@order = order
end

def create
@order = refreshed_order
@order.save
respond_with(@order)
end

def edit
@order = order
end

def update
@order = refreshed_order
@order.save
end

def destroy
@order = order
@order.destroy
end

private

def order
params[:id] ? ensure_access! Order.find(params[:id]) : Order.new
end

def resfreshed_order
order.tap { |o| o.attributes = params[:order] }
end

def ensure_access!(order)
current_user.can_edit?(order) ? order : permission_denied!
end
end

helper_method :order

def new; end
def edit; end

def create
order.save
respond_with(order)
end

def update
order.save
respond_with(order)
end

def destroy
order.destroy
respond_with(order)
end

private

def order
@_order ||= refresh(params[:id] ? ensure_access! Order.find(params[:id]) : Order.new)
end

def resfresh(order)
order.tap { |o| o.attributes = params[:order] if params[:order] }
end

end
end


def new; end
def edit; end

def create
order.save
respond_with(order)
end

def update
order.save
respond_with(order)
end

def destroy
order.destroy
respond_with(order)
end

expose(:order) {
refresh(params[:id] ? ensure_access! Order.find(params[:id]) : Order.new)
}

private

def resfresh(order)
order.tap { |o| o.attributes = params[:order] if params[:order] }
end

end
end

狠狠撸

2013 28-03-dak-why-fp

More Related Content

What's hot (20)

Viewers also liked (12)

Similar to 2013 28-03-dak-why-fp (20)

2013 28-03-dak-why-fp