jg

withConnection :: (Connection -> IO c) -> ReaderT Config IO c
withConnection f = do
  url <- connectionUrl
  liftIO $ bracket (connectPostgreSQL url) (close) f

-- this should be pure!
connectionUrl :: ReaderT Config IO B.ByteString
connectionUrl = do
  config <- ask
  return $ BC.pack (url config)

jg

connectionUrl :: Reader Config B.ByteString

-- withConnection
--   :: (Database.PostgreSQL.Simple.Internal.Connection -> IO c)
--      -> ReaderT Config Data.Functor.Identity.Identity (IO c)
withConnection f = do
  url <- connectionUrl
  return $ bracket (connectPostgreSQL url) (close) f

jg

module AParser where

import           Control.Applicative
import           Data.Char
import Prelude as P


newtype Parser a = Parser { runParser :: String -> Maybe (a, String) }

satisfy :: (Char -> Bool) -> Parser Char

jg

module.exports = function(grunt) {
    grunt.initConfig({
        ts: {
            dev: {                                 // a particular target
                src: ["app/assets/javascripts/**/*.ts"],        // The source typescript files, http://gruntjs.com/configuring-tasks#files
                html: ["app/assets/templates/**/*.tpl.html"], // The source html files, https://github.com/basarat/grunt-ts#html-2-typescript-support
                out: 'public/javascripts/app.js',                // If specified, generate an out.js file which is the merged js file
                watch: 'app/assets/javascripts',                     // If specified, watches this directory for changes, and re-runs the current target
                reference: 'app/assets/javascripts/references.ts',
                options: {                         // use to override the default options, http://gruntjs.com/configuring-tasks#options

jg

# Clone rbenv into ~/.rbenv
git clone git@github.com:sstephenson/rbenv.git ~/.rbenv

# Add rbenv to your PATH
# NOTE: rbenv is *NOT* compatible with rvm, so you'll need to 
# remove rvm from your profile if it's present. (This is because
# rvm overrides the `gem` command.)
echo 'export PATH="$HOME/.rbenv/bin:$HOME/.rbenv/shims:$PATH"' >> ~/.bash_profile
exec $SHELL

jg

import scala.slick.driver.PostgresDriver.simple._
import scala.slick.session.{Database => SlickDatabase}
import Database.threadLocalSession
import scala.slick.jdbc.{GetResult, StaticQuery => Q}
import Q.interpolation
import scala.slick.lifted.CanBeQueryCondition

object SourcesTable extends Table[Source]("sources") {
  def id = column[Long]("id", O.PrimaryKey, O.AutoInc)
  def name = column[String]("name")

jg

// simple example of the cake pattern

// abstract DAO trait
trait Repository[A, B]{
  // saves an entity, returns an ID
  def save(entity: A): B
  // more features..
}

trait RdbmsRepository extends Repository[MyUserCaseClass, Long]{

jg

Backend Architectures

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ror, scala, jetty, erlang, thrift, mongrel, comet server, my-sql, memchached, varnish, kestrel(mq), starling, gizzard, cassandra, hadoop, vertica, munin, nagios, awstats

• Scaling Twitter: Making Twitter 10000 Percent Faster
• Scaling Twitter
• Blaine Cook on Scaling Twitter - YouTube

jg

object TypeSerializers { 
  implicit object LongPropertySerializer extends PropertySerializer[Long] {
    def sqlType = "long"
  }

  implicit object StringPropertySerializer extends PropertySerializer[String] {
    def sqlType = "string"
  }
}

jg

E/AndroidRuntime(30638): FATAL EXCEPTION: main
E/AndroidRuntime(30638): java.lang.NoSuchMethodError: scala.collection.immutable.StringLike.toString
E/AndroidRuntime(30638):        at scala.collection.immutable.StringLike$class.toLong(StringLike.scala:230)
E/AndroidRuntime(30638):        at scala.collection.immutable.StringOps.toLong(StringOps.scala:31)
E/AndroidRuntime(30638):        at com.android.todoapp.Task$$anonfun$deserialize$1.apply(Task.scala:162)
E/AndroidRuntime(30638):        at com.android.todoapp.Task$$anonfun$deserialize$1.apply(Task.scala:160)
E/AndroidRuntime(30638):        at scala.collection.immutable.List.foreach(List.scala:309)
E/AndroidRuntime(30638):        at com.android.todoapp.Task.deserialize(Task.scala:160)
E/AndroidRuntime(30638):        at com.android.todoapp.Task$.deserialize(Task.scala:41)
E/AndroidRuntime(30638):        at com.android.todoapp.Tasks$$anonfun$getTasks$1.apply(Tasks.scala:36)