/tags/scala/ Recent content in Scala on Saleem Ansari Hugo -- gohugo.io en (c) 2024 Saleem Ansari Tue, 08 Dec 2015 10:07:23 -0800 /2015/12/08/scalaquine/ Tue, 08 Dec 2015 10:07:23 -0800 /2015/12/08/scalaquine/ A Scala quine ( program that prints itself ): $ cat ScalaQuine.scala Here it is: object ScalaQuine extends App { val x = """object ScalaQuine extends App {%c val x = %c%c%c%s%c%c%c%c println(x.format('\n', '\"', '\"', '\"', x, '\"', '\"', '\"', '\n', '\n'))%c}""" println(x.format('\n', '\"', '\"', '\"', x, '\"', '\"', '\"', '\n', '\n')) } Compile and run: $ scalac ScalaQuine.scala $ scala ScalaQuine Same as original program: object ScalaQuine extends App { val x = """object ScalaQuine extends App {%c val x = %c%c%c%s%c%c%c%c println(x. /2014/07/20/writing-two-books-with-asciidoc-apache-mahout-and-scala/ Sun, 20 Jul 2014 11:24:05 -0700 /2014/07/20/writing-two-books-with-asciidoc-apache-mahout-and-scala/ For past few weeks I have been gathering my notes on two topics: Machine Learning with Apache Mahout and Programming in Scala. Now I have created two repositories for these two books, with source-code in AsciiDoc format. They are avilable on GitHub. Machine Learning with Apache Mahout Programming in Scala Read on! /2014/07/09/oauth2.0-server-using-play-2.0-framework-in-scala/ Wed, 09 Jul 2014 05:33:56 -0700 /2014/07/09/oauth2.0-server-using-play-2.0-framework-in-scala/ OAuth2.0 supercedes OAuth1.0 protocol, specifically in making it simpler to use. It supports different workflows as described in its specification RFC-6749. The most concise pictorial representation I found is here. I created a Play! 2.0 Application in Scala which supports server to server token exchange using OAuth2.0 Protocol. You can find the project source code on GitHub at play-oauth2-server. Its a complete working server codebase, with: Basic User login Client registration with Callback URL Auth Code generation Authentication Token and Refresh Token generation This application also demonstrates the following: /2014/06/10/creating-desktop-shortcuts-for-scala-ide-on-linux/ Tue, 10 Jun 2014 02:18:11 -0700 /2014/06/10/creating-desktop-shortcuts-for-scala-ide-on-linux/ Download the Scala IDE from here, unzip it at ~/software/scala-eclipse, such that the contents look as follows: $ pwd /home/saleem/software/scala-eclipse $ ls artifacts.xml configuration eclipse eclipse.ini epl-v10.html features icon.xpm META-INF notice.html p2 plugins readme Create a launcher script for Scala IDE /bin/scala-ide, and make it executable: $ cat /bin/scala-ide #!/bin/bash /home/saleem/software/scala-eclipse/eclipse $ chmod +x /bin/scala-ide Configure launcher icon ~/.local/share/applications/scala-ide.desktop. You can copy a config file from /usr/share/applications/ directory and make changes as follows: /2014/06/03/machine-learning-with-mahout-and-scala/ Tue, 03 Jun 2014 22:27:10 -0700 /2014/06/03/machine-learning-with-mahout-and-scala/ This post is coming after a long time. Apologies for that. Alright, this one is for the fans of Apache Mahout and Scala programming language. I had given a talk on Machine Learning with Apache Mahout and Scala ( slides ) at OSDConf.in. The code examples are present on GitHub at this repo. /2014/03/23/scala-at-bootconf-2014/ Sun, 23 Mar 2014 00:23:46 +0530 /2014/03/23/scala-at-bootconf-2014/ I attended BootConf 2014 today. The day began with Arduino for Robotics by Naveen Kumar. It was such a wonderful 1 hour session, purely demo based, and very interactive. Second talk was Varnish Caching Server by Vivek Gupta. Vivek explanined how a caching server fits in a clustered environment and what all things that we can do with Varnish. Next was my talk Introduction to Scala. You can find the slides here, and all the code for demo at this GitHub repository. /2014/02/03/a-simple-scala-parser-to-parse-44gb-wikipedia-xml-dump/ Mon, 03 Feb 2014 00:00:00 +0000 /2014/02/03/a-simple-scala-parser-to-parse-44gb-wikipedia-xml-dump/ I had to parse a Wikipedia XML Dump ( 44GB XML file uncompressed ). The XML dump is available here, and I have also created a smaller sample file to run this code: sample wiki.xml file. Below is the XML event based parser using Scala’s XMLEventReader: package xml import scala.io.Source import scala.xml.pull._ import scala.collection.mutable.ArrayBuffer import java.io.File import java.io.FileOutputStream import scala.xml.XML object wikipedia extends App { val xmlFile = args(0) val outputLocation = new File(args(1)) val xml = new XMLEventReader(Source. /2013/08/25/attending-scalatraits-2013-event-in-new-delhi/ Sun, 25 Aug 2013 00:00:00 +0000 /2013/08/25/attending-scalatraits-2013-event-in-new-delhi/ First of all I was surprised that an event specifically targeted towards Scala was happening in India and very fortunately in New Delhi itself. I attend the ScalaTraits 2013 event in New Delhi a couple of days back. The event was put together by Knoldus, a company specializing exclusively in Scala and related technologies. The agenda was like this: Introductory talk This talk was an introduction to the Scala ecosystem as a whole by Vikas Hazrati. /2013/04/16/on-choosing-play2-framework/ Tue, 16 Apr 2013 00:00:00 +0000 /2013/04/16/on-choosing-play2-framework/ /2013/03/15/emacs-and-akka-pi-example/ Fri, 15 Mar 2013 00:00:00 +0000 /2013/03/15/emacs-and-akka-pi-example/ I was trying The first Akka Example here Install the TypeSafe stack on RPM distro: $ sudo yum install typesafe-stack Setup a g8 project: $ g8 typesafehub/akka-scala-sbt Akka 2.0 Project Using Scala and sbt organization [org.example]: in.tuxdna name [Akka Project In Scala]: akka-pi akka_version [2.0.1]: version [0.1-SNAPSHOT]: The I added the Pi.scala to src/main/scala folder. Then I tried to compile it from within Emacs, to check if it will be easier navigate compilation errors in the code. /2013/02/21/sbt-and-specs-for-bdd-in-scala/ Thu, 21 Feb 2013 00:00:00 +0000 /2013/02/21/sbt-and-specs-for-bdd-in-scala/ I had used RSpec earlier for Behaviour Development Development for a Ruby on Rails project. Today I learnt how to do BDD in Scala. Chapter 4 of Programming Scala introduces Traits and Specs for testing the code. Here is how I set it up: I already had Scala installed. So the first step was to setup sbt ( Simple Build Tool for Scala ). Setup was easy ( described in detail here ): /2013/02/20/scala-script-tool-seems-to-be-broken-fedora-17/ Wed, 20 Feb 2013 00:00:00 +0000 /2013/02/20/scala-script-tool-seems-to-be-broken-fedora-17/ I am running Scala on Fedora 17 and I seem to face a problem. I created a /tmp/hello.scala file, as follows: println("Hello world") This works just fine if I run it on Ubuntu 12.04 i.e. it prints Hello world. However, when I try to run it on Fedora, I don’t get any output and the script keeps waiting forever. So I tried to inspect what’s happening here: $ bash -x scala /tmp/hello. /2013/02/18/set-up-for-learning-scala-with-emacs/ Mon, 18 Feb 2013 00:00:00 +0000 /2013/02/18/set-up-for-learning-scala-with-emacs/ Obviously the first step is to install Scala language. $ sudo aptitude install scala OR $ yum install scala Then I ran my first Scala “Hello world!” program from CLI. Setting up Scala mode for Emacs was a bit of a pain so I merged the old scala-mode and the latest into my repo. Here are very simple steps to setup scala-mode for Emacs. $ cd ~/.emacs.d/ $ git clone git://github.