#Scala Exercises

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How it works

"Scala Exercises" brings exercises for the Stdlib, Cats, Shapeless and many other great libraries for Scala to your browser. Offering hundreds of solvable exercises organized into several categories covering the basics of the Scala language and it's most important libraries.

• LEARN: Each category includes an explanation of the basics. Learn the concepts through simple code samples.

• SOLVE: Each exercise is a unit test that must pass successfully, complete the exercise by filling in the blanks. Receive instant feedback as your answers are validated in real-time.

• SHARE: The system will consider the category complete when all its exercises are successfully done. Don't forget to share your progress on social networks before moving on to the next category!

• EDIT: After completing a category, you'll be able to go back and edit it. Add new exercises or improve existing ones by sending a pull-request.

Getting Started

Prerequisites

• Install JDK 8, either the Oracle version or OpenJDK
• Install Scala
• Install SBT
• Install PostgreSQL 9.4
• Install the Sass Ruby gem and make sure the sass program can be run

Installing the app locally

First of all, either clone the repository via git

$ git clone https://github.com/scala-exercises/scala-exercises

or download it

$ wget https://github.com/scala-exercises/scala-exercises/archive/master.zip

You'll need a working PostgreSQL 9.4 database and user for running the app. Once the database is running, create a user called scalaexercises_dev_user

$ createuser -P -e scalaexercises_dev_user "a_password"

Create a db called scalaexercises_dev and grant all privileges on it to scalaexercises_dev_user

$ createdb scalaexercises_dev
$ psql -c "GRANT ALL PRIVILEGES ON DATABASE scalaexercises_dev TO scalaexercises_dev_user;"

Edit the site/server/conf/application.dev.conf configuration file with your database information.

Running the app

Go into the site directory, run sbt run

$ cd site/
$ sbt run

After compilation the application will be running, listening in the 9000 port. Point your browser to localhost:9000 and start having fun!

Troubleshooting

If you use ensime and you have configured the sbt-ensime plugin in your sbt user global settings, likely you might have this issue running the application locally:

java.lang.NoClassDefFoundError: scalariform/formatter/preferences/SpacesAroundMultiImports$

In that case, you could solve this issue setting up your /.sbt/0.13/plugins/plugins.sbt file as follow:

addSbtPlugin("org.ensime" % "ensime-sbt" % "0.4.0")

dependencyOverrides in ThisBuild += "org.scalariform" %% "scalariform" % "0.1.8"

Project structure

The project has two main directories, core and site, each with a SBT project.

The core directory contains an exercise runtime and exercise compiler. These allow exercises to be defined using regular Scala which is compiled into an exercise library.

The site directory contains the Play website as well as some pre-packaged exercise content. These items depend on components in core.

At the moment, site and core are coupled tightly. Once this project is a bit more stable the exercise compiler plugin will be published and it will be easy to create new exercises for existing Scala libraries.

Contributing

Contributions welcome! At this time, we don't have an official contribution guide, so please join our Gitter channel to get involved.

##License

Copyright (C) 2015-2016 47 Degrees, LLC. Reactive, scalable software solutions. http://47deg.com hello@47deg.com

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 distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.