[Swift] Implement new Concept Exercise: dictionaries

[wneumann]

This issue describes how to implement the dictionaries concept exercise for the Swift 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 the following documents:

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

Please also watch the following video:

• The Anatomy of a Concept Exercise.

Goal

This concept exercise should convey a basic understanding of how to work with Sets in Swift.

Things to teach

• Initializing empty dictionaries
• Initializing sets from dictionary literals
• Inserting key/value pairs
• Retrieving values
• Iterating over a dictionary

Things not to teach

• Hashable requirement for keys

Concepts

• dictionaries

Prerequisites

• basics
• arrays
• optionals

Resources to refer to

Hints

• Dictionaries
• Dictionary documentation

After

• Dictionaries
• Dictionary documentation

Representer

TBD

Analyzer

TBD

Implementing

See the Swift track implementation guide for guidance.

Help

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

[wneumann]

PR Added

[wneumann]

Closed with PR https://github.com/exercism/v3/pull/1961