Mat MatMoore

What is the appeal of dynamically-typed languages?

Kris Nuttycombe asks:

I genuinely wish I understood the appeal of unityped languages better. Can someone who really knows both well-typed and unityped explain?

I think the terms well-typed and unityped are a bit of question-begging here (you might as well say good-typed versus bad-typed), so instead I will say statically-typed and dynamically-typed.

I'm going to approach this article using Scala to stand-in for static typing and Python for dynamic typing. I feel like I am credibly proficient both languages: I don't currently write a lot of Python, but I still have affection for the language, and have probably written hundreds of thousands of lines of Python code over the years.

The introduction to Reactive Programming you've been missing

(by @andrestaltz)

This tutorial as a series of videos

If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.

What you'll need

nginx
nginx-x-rid-header module (https://github.com/newobj/nginx-x-rid-header)

Why?

We want to track image downloads from client side and in javascript we cannot get the header values:(.

Logging

First, install the following libraries:

$ brew install unixodbc
$ brew install freetds --with-unixodbc

FreeTDS should already work now, without configuration:

$ tsql -S [IP or hostname] -U [username] -P [password]
locale is "en_US.UTF-8"

locale charset is "UTF-8"

	-module(dojo4).
	-import(lists,[nth/2]).
	-include_lib ("eunit/include/eunit.hrl").
	-compile(export_all).

	rand_list(Size) ->
	lists:map(fun(X)-> random:uniform(100) end, lists:seq(1,Size)).

	grid(Size) ->
	lists:map(fun(X)-> rand_list(Size) end, lists:seq(1,Size)).

	package adventure

	import scala.collection.mutable.{ Map => MMap }

	trait Direction
	case object North extends Direction
	case object South extends Direction
	case object East extends Direction
	case object West extends Direction
	case object Wrong extends Direction

	object scratch {

	type SentenceAnagram = Set[String]
	type SolutionSpace = Set[SentenceAnagram]
	type CharacterCounts = Map[Char, Int]
	def frequencyCount(word: String): CharacterCounts = {
	val grouped: Map[Char, String] = word.toLowerCase.replaceAll("[^a-z]", "").groupBy(c => c)
	grouped.map((pair: Tuple2[Char, String]) => (pair._1, pair._2.length))
	}

	def userId(username: String): Option[Int] =
	Some(1)

	def mostRecentOrderId(userId: Int): Option[Int] =
	Some(2)

	def orderCost(orderId: Int): Option[Int] =
	Some(3)

	def mostRecentOrderCost(username: String): Option[Int] =

	object Compiler extends Application {

	val program = "++++++++++" +
	"[" +
	">+++++++" +
	">++++++++++" +
	">+++" +
	">+" +
	"<<<<-" +
	"]" +

	#include <stdio.h>
	#include <stdlib.h>
	#include <stdint.h>
	#include <string.h>

	#define HASHMASK 0xFFFF


	uint64_t hash(const char* key, uint64_t seed)
	{