01-introduction.md

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Introduction

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Course overview

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• In this course we will:
  • Start from an existing Scala (2.13)/Akka Typed (2.6) based application
  • Apply features introduced in the Scala language as part of the Scala 3 project

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• The objective is to illustrate how these new features:
  • Bring added value and can simplify Scala code
  • Remove some of the inconsistencies or warts from the Scala 2 language

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Course prerequisites

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• The participants should have practical experience with the Scala 2 language
• The course has a number of exercises and each student should have a computer with the following installed:
  • JDK 11 (e.g. AdoptOpenJDK 11)
  • sbt
  • An editor or IDE of your choice configured to work with Scala 3 code
    • Possible options are:
      • Metals with your client of choice (Visual Code Studio, Vim, etc…)
      • IntelliJ IDE with the Scala plugin installed and configured to use the nightly build
• Optionally install the Scala 3 compiler and Scala 3 REPL
  • This can be done using Coursier:
    • cs install scalac:3.3.0
    • cs install scala:3.3.0

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Preparing for the exercises

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• Download the student-ready version of the exercises here
• Unzip the downloaded artefact and cd into the lunatech-scala-2-to-scala3-course folder
  • This folder contains an sbt project that contains all the exercises
• Start an sbt session in the root folder
• Load the project into your favourite development environment (IDE)

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Student exercise repository functionality

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• We use the cmtc command from the command line to navigate the course.

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Agenda - I

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• Course Overview
• Scala 3 Migration course
  • Setting up the Scala 3 Migration Tool
  • Migrating:
    • Scala dependencies
    • Scala compiler options
    • Scala syntax
    • Types
• Moving from Scala 2 to Scala 3 workshop/course
  • A recap on:
    • Scala 2
    • The Scala 3 project
    • The Akka Toolkit
  • A [detailed] look at the Scala 2/Akka Typed based Sudoku Solver

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Agenda - II

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• Scala 3 features & exercises:
• scala3-compiler code rewrite capabilities
  • Top Level Definitions
  • Parameter Untupling
  • Extension methods
  • Contextual Abstractions (given instances, using clauses, summoning instances)
  • Enumerations and export clauses
  • Intersection Types and Union Types
  • Opaque Type Aliases
  • Multiversal Equality
• Wrap-up & Conclusions

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The teachers

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• Eric Loots (Lunatech Belgium)
• Adrien Piquerez (EPFL Scala Center Switzerland)
• Trevor Burton-McCreadie (Lunatech United Kingdom)

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You!

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• Briefly introduce yourself (Name? Where do you live/work? Passions, ...)
• What is your connection with Scala [3]?
• Please share your experience with Scala and your migration experiences, if any.
• What would you like to learn in the coming two days?