dskecse

function extend(destination, source) {
    for (var meth in source) {
        if (source.hasOwnProperty(meth)) {
            destination[meth] = source[meth];
        }
    }
    return destination;
}

dskecse

require 'English'

module NoDoubleRaisable
  def error_handled!
    $ERROR_INFO = nil
  end
  
  def raise(*args)
    if $ERROR_INFO && args.first != $ERROR_INFO
      warn "Double raise at #{caller.first}, aborting."

dskecse

def honorific(klass):
    class HonorificClass(klass):
        def full_name(self):
            return 'Dr. ' + super(HonorificClass, self).full_name()
    return HonorificClass

@honorific
class Person(object):
    def __init__(self, first, last):
        self.first = first

dskecse

require 'benchmark/ips'

ARRAY = (1..10).to_a

Benchmark.ips do |x|
  x.report('each') { sum = 0; ARRAY.each { |n| sum += n }; sum }
  x.report('reduce') { ARRAY.reduce(0, :+) }
end

Calculating -------------------------------------

dskecse

defmodule MyEnum do
  def all?([head | tail], func \\ fn x -> x end) do
    func.(head) && all?(tail, func)
  end
  def all?([], _), do: true

  def each([], _), do: []
  def each([head | tail], func) do
    [func.(head), each(tail, func)]
  end

dskecse

defmodule Recursive do
  def map([], _func), do: []
  def map([head | tail], func), do: [func.(head) | map(tail, func)]
end

dskecse

defmodule Recursive do
  def len([]), do: 0
  def len([_head | tail]), do: 1 + len(tail)
end

IO.puts Recursive.len([1, 2, 3])
# => 3

dskecse

:io.format "The number is ~.2f~n", [5.578]
# => "The number is 5.58"

System.get_env "RUBYOPT"
# => "-rauto_gem"

Path.extname "dave/test.exs"
# => ".exs"

System.cwd

dskecse

convertStringToAction :: String -> Action
convertStringToAction str = case str of
  "Look"    -> Look
  "New"     -> New
  otherwise -> Quit

-- guards (охранные выражения)
convertStringToAction' :: String -> Action
convertStringToAction' str | str == "Look" = Look
                           | str == "New"  = New

dskecse

--     | ln (abs(sin(x))), if x > 5
-- y = | x^2 + a^2,        if x <= 5 and a <= 3
--     | x / a + 7.8*a,    if x <= 5 and a > 3

y x a = if x > 5
        then log (abs (sin (x)))
        else
          if x <= 5 && a <= 3
          then x^2 + a^2
          else x / a + 7.8 * a