Functional programming is becoming increasingly widespread in industry. This trend is driven by the adoption of Scala as the main programming language for many applications. Scala fuses functional and object-oriented programming in a practical package. It interoperates seamlessly with both Java and Javascript. Scala is the implementation language of many important frameworks, including Apache Spark, Kafka, and Akka. It provides the core infrastructure for sites such as Twitter, Tumblr and also Coursera. In this course you will discover the elements of the functional programming style and learn how to apply them usefully in your daily programming tasks. You will also develop a solid foundation for reasoning about functional programs, by touching upon proofs of invariants and the tracing of execution symbolically. The course is hands on; most units introduce short programs that serve as illustrations of important concepts and invite you to play with them, modifying and improving them. The course is complemented by a series programming projects as homework assignments. Recommended background: You should have at least one year programming experience. Proficiency with Java or C# is ideal, but experience with other languages such as C/C++, Python, Javascript or Ruby is also sufficient. You should have some familiarity using the command line.
Tools Setup for Mac OS X
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Do curso por École Polytechnique Fédérale de Lausanne
Functional Programming Principles in Scala
5882 classificações
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École Polytechnique Fédérale de Lausanne
5882 classificações
Curso 1 de 5 em Specialization Functional Programming in Scala
Na lição
Getting Started + Functions & Evaluation
Get up and running with Scala on your computer. Complete an example assignment to familiarize yourself with our unique way of submitting assignments. In this week, we'll learn the difference between functional imperative programming. We step through the basics of Scala; covering expressions, evaluation, conditionals, functions, and recursion
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Martin OderskyProfessor
Computer Science
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 OSX. If you're using a different operating
system, check the getting started section on the video lectures part of the class
website. Everything that we show in this video is
also explained in text on the Tools Set Up 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 the JDK, the Java Runtime Environment, which is used to execute
Scala programs. The second one is SBT, a build tool for
Scala, which you will also use to submit your assignment solutions to Coursera.
The third one is the Scala IDE 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 OS10, we will look at how to install JDK on Mac
OSX. In fact, Mac OSX either comes with Java
pre-installed or it will install it automatically for you.
To verify, if you already have Java, you have to open a terminal application.
So, you open the Finder, we go to the Applications folder and we open the
Utilities folder. In utilities, there's 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 window, 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 machine 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
license agreements. Okay.
So, once the Java installation has finished, we just click Okay and we run
Java minus 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 on to the second tool 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 the homebrew package manager 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 navigate to the file 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 a new Finder window, and in my
home folder I create a subdirectory named applications.
Now, I take the extracted SBT folder and I move it to my newly created Applications
folder. Inside the SBT folder, you have a bin
subdirectory, which contains the executable files for SBT.
So, let's close the Finder window and go back to the tutorial.
So, we downloaded SBT, we unpacked the Archive, and moved it to the Applications
folder. And, and what we need to do last is adding
the bin directory of SBT to the path environment variable.
In order to do that, you have to open the file.bash<u>profile which is located in</u>
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 lets check if the bash<u>profile file already exists.</u> So, we type
ls.bash<u>profile. In my case, the file does no exist yet</u>
but it might very well be that you already have it.
So, in order to create or edit a file, we can use the Nano Text Editor, which is a
very simple command-line text editor. We type, nano.ash<u>profile and hit</u>
Enter. So now, we need to add one export command to dispatch 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 were we actually extracted SBT.
In my case, this was /users/luc, my username, /applications, and then SBT bin
Now, we can exit the Nano text editor using Control+X, and we will save the
changes to the file by confirming with Y and then 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-H. If the installation was successful, then
you'll see SBT Help message appear on the screen.
Okay, so, we close the Terminal window, we go back to the set up instructions and we
go to the last tool that we have to install, the is Scala IDE four eclipse.
In order to install this Scala IDE, we have to open this website and scroll down
to the downloads. 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.
Once the download of the Scala IDE has finished, we open the Download folder in
Finder. We unpack the Scala IDe by simply double
clicking the file. Since, the Scala IDE is on applications
that we will reuse in the future, we will also move it to our Applications folder.
So, I open a new window, I go to my Applications folder, and then move the
Eclipse folder into my applications. In order to open the Scala IDE, you simply
go into the Eclipse folder and you double click the Eclipse file.
When starting up Eclipse, you have to define which your, workspace 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 a new folder
named ProgFun Workspace. I will select the folder and click Open.
By clicking Okay, Eclipse will start up using that new workspace.
Okay, in order to test the Scala IDE, we'll go back to the tool set of
instructions page. We can close the Download page, and the
Tool Setup page explains you to create a simple Hello World project in the Scala
IDE. I will show you how to do this now.
So, you go to Eclipse and in the menu , you select File, New Scalar 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 a project, and we right-click on the Source folder, and select U Scala
object. We give the object a name, in this case,
Hello. And we define in which package job check
we defined, so we put here the package greeter.
We confirm by clicking Finish. Okay, now, the source code for the Hello
World application can be found on the Tools Setup 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 saved the file and, you can notice that
once you save the file, Eclipse will automatically compile the entire project
for you. In order to execute the Hello World
application, you simply have to right click on the hello.scala source file,
select Run S, and select Scala application.
You will see the output of the Hello World program in the, in the eclipse console.
The next feature that we are going to show you, is a brand new feature named the
Scala worksheet. In a 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 worksheet.
Now, to try out the worksheet, we have prepared some instructions for you that
you can paste into 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 Scala worksheet.
Okay. Once you save to file, Eclipse will
automatically evaluate at 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 assigned the number one to the value x.
We define the function increase which returns its argument increase by one.
Every test increase by invoking it and passing x into the function.
You can see that increase of x returns two.
Now, if you go back to Worksheet, and change the definition of x, for instance
to be five, 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 six.
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