viktorklang

/*
Copyright 2012-2021 Viktor Klang

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software

sadache

package controllers

import play.api._
import play.api.mvc._
import play.api.libs.ws._
import play.api.libs.iteratee._
import play.api.libs.concurrent._

object Application extends Controller {
	

sadache

package controllers

import play.api._
import play.api.mvc._


object Application extends Controller {
  
  def index = Action {

jboner

Latency Comparison Numbers (~2012)
----------------------------------
L1 cache reference                           0.5 ns
Branch mispredict                            5   ns
L2 cache reference                           7   ns                      14x L1 cache
Mutex lock/unlock                           25   ns
Main memory reference                      100   ns                      20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy             3,000   ns        3 us
Send 1K bytes over 1 Gbps network       10,000   ns       10 us
Read 4K randomly from SSD*             150,000   ns      150 us          ~1GB/sec SSD

gclaramunt

trait FlightStatus
trait Flying extends FlightStatus
trait Landed extends FlightStatus

case class Plane[Status <: FlightStatus]()

def land(p:Plane[Flying])=Plane[Landed]()
def takeOff(p:Plane[Landed])= Plane[Flying]()

val plane = new Plane[Landed]()

ckirkendall

(use '[clojure.core.match :only [match]])

(defn evaluate [env [sym x y]]
  (match [sym]
    ['Number]   x
    ['Add]      (+ (evaluate env x) (evaluate env y))
    ['Multiply] (* (evaluate env x) (evaluate env y))
    ['Variable] (env x)))
    
(def environment {"a" 3, "b" 4, "c" 5})

sadache

If your csv doesn't contain escaped newlines then it is pretty easy to do a progressive parsing without putting the whole file into memory. The iteratee library comes with a method search inside play.api.libs.iteratee.Parsing :

def search (needle: Array[Byte]): Enumeratee[Array[Byte], MatchInfo[Array[Byte]]]

which will partition your stream into Matched[Array[Byte]] and Unmatched[Array[Byte]]

Then you can combine a first iteratee that takes a header and another that will fold into the umatched results. This should look like the following code:

// break at each match and concat unmatches and drop the last received element (the match)

gordonad

<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
           http://maven.apache.org/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.gordondickens.sample</groupId>
  <artifactId>sample-parent</artifactId>
  <version>1.0.0</version>

  <packaging>pom</packaging>

kevinwright

case class ZeeingEvent(
  zid: String,
  kind: String,
  showId: String,
  show_name: Option[String],
  time: DateTime
) {
  require (kind == "StartedZeeing" || kind == "EndedZeeing")
}

headius

Too much for teh twitterz :)

JVM + invokedynamic is in a completely different class than CLR + DLR, for the same reasons that JVM is in a different class than CLR to begin with.

CLR can only do its optimization up-front, before executing code. This is a large part of the reason why C# is designed the way it is: methods are non-virtual by default so they can be statically inlined, types can be specified as value-based so their allocation can be elided, and so on. But even with those language features CLR simply cannot optimize code to the level of a good, warmed-up JVM.

The JVM, on the other hand, optimizes and reoptimizes code while it runs. Regardless of whether methods are virtual/interface-dispatched, whether objects are transient, whether exception-handling is used heavily...the JVM sees through the surface and optimizes code appropriate for how it actually runs. This gives it optimization opportunities that CLR will never have without adding a comparable profiling JIT.

So how does this affect dynamic