Implement new Concept Exercise: constructors

Read languages/fsharp/reference/implementing-a-concept-exercise.md and the linked v3 concept-exercise documentation first. Compare the structure and metadata in languages/fsharp/exercises/concept/numbers/.meta/config.json and .meta/design.md, then inspect the implemented-exercises list. Done means the constructors concept exercise follows the F# track conventions, covers the stated objectives and prerequisites, and needs no representer or analyzer changes.

This issue describes how to implement the constructors 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 Constructors in F#.

Learning objectives

• Know what constructors are.
• Know the difference between primary and additional constructors.
• Know how to define additional constructors.
• Know how to add functionality to constructors using do bindings.
• Know that constructors are regular functions.

Out of scope

• Static do bindings.

Concepts

The Concepts this exercise unlocks are:

• constructors: know what constructors are; know the difference between primary and additional constructors; know how to define additional constructors; know how to add functionality to constructors using do bindings; know that constructors are regular functions.

Prerequisites

This exercise's prerequisites Concepts are:

• classes: know what records are.
• method-overloading: know how method overloading works.

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

Resources to refer to

Hints

• Constructors: introduction to constructors.
• do bindings in constructors: how to use do bindings to add constructor logic.
• Additional constructors: how to define additional constructors.

After

• Constructors: introduction to constructors.
• do bindings in constructors: how to use do bindings to add constructor logic.
• Additional constructors: how to define additional constructors.

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.