Implement new Concept Exercise: classes

[ErikSchierboom]

This issue describes how to implement the classes concept exercise for the F# track.

Getting started

Please please please read the docs before starting. Posting PRs without reading these docs will be a lot more frustrating for you during the review cycle, and exhaust Exercism's maintainers' time. So, before diving into the implementation, please read up on the following documents:

• The features of v3.
• Rationale for v3.
• What are concept exercise and how they are structured?

Please also watch the following video:

• The Anatomy of a Concept Exercise.

Goal

The goal of this exercise is to teach the student the basics of the Concept of Classes in F#.

Learning objectives

• Know what classes are.
• Know what the difference is between classes and records and when to use which.
• Know what encapsulation is.
• Know what fields are.
• Know how to create an object.
• Know how to define methods.

Out of scope

• Static bindings.
• Mutable values.
• Properties.
• Composition.
• Additional constructors.
• do bindings in classes.
• let and val bindings in a class.
• Interfaces.
• Inheritance.
• Properties.
• Indexers.
• Structs.
• Method overloading.

Concepts

The Concepts this exercise unlocks are:

• classes: know what classes are; know what the difference is between classes and records and when to use which; know what encapsulation is; know what fields are; know how to create an bject; know how to define methods; know how to update state.

Prerequisites

This exercise's prerequisites Concepts are:

• records: know what records are.
• tuples: know what tuples are (used for parameter passing).
• access-control: know about the public and private access control
• unit: know about the unit type.

Any data types used in this exercise (e.g. strings or integers) should also be added as prerequisites.

Resources to refer to

Hints

• Classes: introduction to classes.
• Constructors: how to define primary and additional constructors, and how to create objects by calling a constructor.
• Methods: how to define methods in classes.
• let bindings in classes: how to use let bindings to define fields.
• do bindings in classes: how to use do bindings to add constructor logic.
• val keyword: describes val fields.
• unit : describes the unit type.

After

• Classes: introduction to classes.
• Constructors: how to define primary and additional constructors, and how to create objects by calling a constructor.
• Methods: how to define methods in classes.
• let bindings in classes: how to use let bindings to define fields.
• do bindings in classes: how to use do bindings to add constructor logic.
• val keyword: describes val fields.
• unit : describes the unit type.

Representer

This exercise does not require any specific representation logic to be added to the representer.

Analyzer

This exercise does not require any specific logic to be added to the analyzer.

Implementing

To implement this exercise, please follow these instructions.

Help

If you have any questions while implementing the exercise, please post the questions as comments in this issue.