[v3] Implement new Concept Exercise: Ranges

[wneumann]

This issue describes how to implement the Ranges 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 Ranges and ClosedRanges in Swift.

Learning objective

• Know how to create a Range
• Know how to create a ClosedRange
• Know the difference between Range and ClosedRange
• Know how to pattern match Ranges
• Know that Ranges can be used with types other than Int and what, e.g. a ClosedRange<String> means.
• Know how to iterate over a Strideable Range (perhaps just talk about Ints and not bring up Strideable`)

Out of scope

• Mapping, filtering, reducing, etc.
• Strideable protocol

Concepts

• Range
• ClosedRange
• …

Prerequisites

• conditionals
• numbers
• strings-and-characters

Resources to refer to

Hints

• range operators
• for-in loops
• expression patterns

After

• range operators
• for-in loops
• expression patterns
• closed range docs
• range docs

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.

##Edits