ProjectScala

HOW TO CREATE A SCALA PROJECT

#Installations

1. Make sure you have the Java 8 JDK (also known as 1.8) Run javac -version in the command line and make sure you see javac 1.8.___ If you don’t have version 1.8 or higher, install the JDK
2. Install sbt

Create the project

1. cd to an empty folder.
2. Run the following command sbt new scala/hello-world.g8. This pulls the ‘hello-world’ template from GitHub. It will also create a target folder, which you can ignore.
3. When prompted, name the application hello-world. This will create a project called “hello-world”.
4. Let’s take a look at what just got generated:

• hello-world

  • project (sbt uses this to install manage plugins and dependencies)

    • build.properties
    • src
      • main
      • scala (All of your scala code goes here) -Main.scala (Entry point of program) <-- this is all we need for now

    -build.sbt (sbt's build definition file)

After you build your project, sbt will create more target directories for generated files. You can ignore these.

#Running the project

1. cd into hello-world.
2. Run sbt. This will open up the sbt console.
3. Type ~run. The ~ is optional and causes sbt to re-run on every file save, allowing for a fast edit/run/debug cycle. sbt will also generate a targetdirectory which you can ignore.

#Modifying the code

1. Open the file src/main/scala/Main.scala in your favorite text editor.
2. Change “Hello, World!” to “Hello, New York!”
3. If you haven’t stopped the sbt command, you should see “Hello, New York!” printed to the console.
4. You can continue to make changes and see the results in the console.

#Adding a dependency

Changing gears a bit, let’s look at how to use published libraries to add extra functionality to our apps.

1. Open up build.sbt and add the following line: libraryDependencies += "org.scala-lang.modules" %% "scala-parser-combinators" % "1.1.0"

Here, libraryDependencies is a set of dependencies, and by using +=, we’re adding the scala-parser-combinators dependency to the set of dependencies that sbt will go and fetch when it starts up. Now, in any Scala file, you can import classes, objects, etc, from scala-parser-combinators with a regular import. You can find more published libraries on Scaladex, the Scala library index, where you can also copy the above dependency information for pasting into your build.sbt file

Using links: https://docs.scala-lang.org/getting-started.html

https://docs.scala-lang.org/getting-started-sbt-track/getting-started-with-scala-and-sbt-on-the-command-line.html

https://docs.scala-lang.org/getting-started-sbt-track/testing-scala-with-sbt-on-the-command-line.html