Hi. In this video we are going to show you how to install the tools required for our class on your machine. This video is for people using Mac OS X. If you're using a different operating system, check the Getting Started section on the Video Lectures part of the class website. Everything that is shown in this video is also explained in text on the tool setup wiki page on the class website. So, let's have a look at this page. As you can see, there are three things that you need to install on your machine in order to prepare for this class. The first one is JDK, the Java runtime environment, which is used to execute Scala programs. The second one is SBT, a built tool for Scala, which will also use to submit your assignment solutions to Coursera. The third one is the Scala ID for Eclipse, which is the IDE that we are going to use in this class. Okay. So let's get started by installing the Java debug kit. Every section in this tutorial has three sub sections. one for each operating system. Since we are currently on Mac OS 10 we will look at how to install the JDK on Mac OS X. In fact Mac OS X either comes with Java preinstalled, or it will install it automatically for you. To verify if you already have Java, you have to open a terminal application. So, if you open the finder, we go to the Applications folder, and we open the Utilities folder. In Utilities, there is the application named Terminal. Since we will be using the Terminal a lot in this class, it makes sense to Drag it into your Dock. Okay, so we can close the Finder right now. Open a Terminal. And now we want to verify if we have Java installed. In order to do that, you type Java minus version into the terminal. On this version, I don't have Java installed yet. So I will get the window which tells me to open Java, I actually need to install it. So the only thing you need to do is click the Install button. Of course you have to agree to the licence agreements. Okay, so once the Java installation has finished, we just click OK and we run Java Linux version again. Now we see the version number of the Java installation that has been installed. Okay, so we close this terminal window and we move onto the second word that we need to install. The second tool that we need to install is SBT. In order to install SBT on your system, you can either use home brew package match or, or you can do a manual installation. In this video I will do a manual installation. So we download SBT from this url. Once the download has finished we now begin to find it in the finder and we double click it to extract SBT. Okay so since SBT is an application that we will reuse in the future we will move it to a different location. So I open it and you find a window. And in my home folder I create the sub directory named applications. [SOUND] Now I take the extracted SBT folder, and I move it to my newly-created Applications folder. Inside the SBT folder you have a big subdirectory which contains the executable files for SBT. So let's close the finder windows and go back to the tutorial. So we downloaded SBT, we unpacked the archive. And moved it to the Applications folder. And what we need to do last is add in the bin directory of SBT to the path environment variable. In order to do that you have to open the file. bash on your score profile which is located in your home directory. If the file doesn't exist yet, you will have to create it. Okay, so let's open a new terminal window. And let's check if the batch profile file already exists. So we type ls. bash_profile . In my case, the file does not exist yet. But it might very well be that you already have it. So, in order to create or edit the file, we can use the nano text editor, which is a very simple common line text editor. We type nano. bash_profile and hit enter. So now we need to add one Export command to this batch profile file. We go back to the setup instructions. We copy the Export command, right click Copy and go back to the terminal. And paste it using right-click Paste. Now in fact, we have to change the path of our SBT installation to match the path where we actually extracted SBT. In that case, this was /users/uc, my username, /applications And then SBT bit. Now we can exit the nano text editor using control-x and we will save the changes to the file by control with y and hitting enter for the file name. Okay, now we need to verify if SBT has been installed correctly. We close the terminal window and we go back to the instructions. In order to verify the SBT installation we have to start a new terminal window and we have to type SBT minus H. If the installation was successful, then you will see the SBT help message appear on the screen. Now you have to find the version of the Scala IDE which matches your operating system. In my case, I am on a 64 bit Mac OSX so I click this link. [SOUND] Once the download of the Scala IDE has finished. We open the download folder in the Finder. We unpack the Scala IDE by simply double-clicking the file. Since the Scala IDE is an application that we will resue in the future, we will also move it to our Applications folder. So I open a new window. I go up to my applications folder, and I move the eclipse folder into my applications. In order to open the Scala ID you simply go into the eclipse folder and you double click the eclipse file. When starting up Eclipse, you have to define which work space you want to use. We recommend that you create one work space, which you can then reuse for all the assignments of our class. I will do this now by clicking the Browse button and going to my Home folder. Okay, so now here I will create the new older named prog fun word space. I will select the folder and click Open. By clicking OK eclipse will start up using that new work space. OK in order to test the Scala ID we go back to the tool set of instructions page. We can close the download page. And the tool setup page explains you to create the simple hello world project in Scala IDE. I will show you how to do this now. So you go to eclipse and in the menu you select File > New > Scala Project. You give the project a name, for instance, Hello World. Okay, in order to enter the source code for the Hello World application We have to create a new scala object. So we open the project, and we right click on the source folder, and select New > Scala Object. We give the object a name. In this case, hello. And we define in which package the object is defined. So we put here the package greeter. We confirm by clicking finish. Okay, now the source code for the hello word application can be found under tools, set up instructions. So we go back to the wiki page and we scroll down to find the source code that we need. We select it, copy it. Go back to Eclipse. And just paste it into the file. We save the file, and you can notice that once you save a file, Eclipse will automatically compile the entire project for you. In order to execute the Hello World appllication You simply have to right-click on the hello.scala source file, select Run As, and select Scala Application. You will see the output of the Hello World program in the e, in the Eclipse console. The last feature that we are going to show you, is a brand new feature named the Scala Worksheet. In the Scala worksheet, you can type arbitrary Scala expressions. And see them evaluated on the fly. It's a great tool to learn and explore Scala. In order to create the worksheet, we right-click on the Create Package, we select New Scala worksheet. You have to give the worksheet a name, and click finish to create it. Okay, I will increase the size of this window in order to see all the, all the words. [NOISE] Now to try out the worksheet we have prepared some instructions for you that you can paste in to this newly created object. So if you go back to the set up instructions, and scroll down to the bottom of the page, you will see a few lines of code that you can copy and paste back in this freshly created scholar worksheet. [NOISE] Okay. Once you save the file, eclipse will automatically evaluate all the lines that are part of the worksheet, and show the result of the evaluation on the right hand side. In this example, we assign the number one to the value x. We define a function increase, which returns its argument decrease by one. And we test increase by invoking it and passing x into the function. You can see that an increase of x returns two. Now, if you go back in the worksheet and change the definition of x, for instance, to be 5. As soon as we save the file, the whole buffer will be reevaluated. And you can see that the result of the invocation of increase is now 6.
