What is Scala?

• Functional/OO multiparadigm language

• Statically and strongly typed

• Runs on the JVM (Java)

• Combines elements of languages like Haskell, OCaml, Java, Erlang

• Killer features:

  • Higher order functions, first class functions (e.g. 'map', 'flatMap

  • 'case class'es - i.e. data classes

  • pattern matching

  • emphasis on immutability

Installation

• Only need a few things to be productive:
  • 'sbt' - scala's build tool
    • Think: maven, gradle, npm, leiningen
    • OS X: `brew install sbt`
  • JDK8+ - Scala runs on the JVM
  • Text editor or IntelliJ IDEA

sbt tasks

• Important tasks
  • 'clean' - removes compiled .class files and other artifacts in target/ folder, akin to clearing cache
  • 'compile' - compiles your project
  • 'test' - runs tests
  • 'run' - runs your code if it can find a main
• Prefixing '~' to tasks will place a continuous watch on the project and will re-execute on writes (~compile will recompile the whole project on file saves)

Typical Project Structure

• src/main/scala/... - source code
• build.sbt - Build file (like package.json)
• target/ - generated classes, artifacts, jars, etc
• project/build.properties - sets sbt version
• project/plugins.sbt - sbt plugins

(can be divided into subprojects, more on that in the future)

Light Intro to Some(Scala Features)

• 'Container' types and what they represent
  • Option - a value or lack thereof
  • Try - a value or failure wrapped over exception
  • Future - async value or failure wraped over exception
• Case classes - data classes with default immutable fields, pattern matching
• Higher order functions - e.g. List.map
• For-comprehensions