Implement new Concept Exercise: maps

[ErikSchierboom]

This issue describes how to implement the maps 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 Maps in F#.

Learning objectives

• Know of the existence of the Map type.
• Know how to define a map.
• Know that maps have structural equality.
• Know that maps are immutable.
• Know how to add and update elements in a map.
• Know how to find or access elements in a map by key.
• Know some basic map functions (like checking if a map is empty).

Out of scope

• Memory and performance characteristics.

Concepts

The Concepts this exercise unlocks are:

• maps: know of the existence of the Map type; know how to define a map; know that maps have structural equality; know that maps are immutable; know how to add and update elements in a map; know how to find or access elements in a map by key; know some basic map functions (like checking if a map is empty).

Prerequisites

This exercise's prerequisites Concepts are:

• higher-order-functions: know how to use higher-order functions.
• generic-types: know how generic types work.

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

Resources to refer to

Hints

• Maps: introduction to maps.
• Map module: the Map module's functions.

After

• Maps: introduction to maps.
• Map module: the Map module's functions.

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.