Add Ranges concept

concepts/ranges/.meta/config.json

@@ -0,0 +1,7 @@
+{
+  "authors": [
+    "colinleach"
+  ],
+  "contributors": [],
+  "blurb": "Ranges represent a sequence of consecutive elements, ascending or descending, and typically integers or characters."
+}

concepts/ranges/about.md

@@ -0,0 +1,56 @@
+# About Ranges
+
+Suppose you want all the non-negative integers up to 1000.
+It would be ridiculous if you had to type all these into a list!
+
+Kotlin, like many languages, has a [`Range`][ref-range] type to simplify this.
+
+Most simply, a range can be consecutive integers.
+To make clear what is included, most of the following examples convert the [`Range`][ref-range-lib] type (a [`lazy`][wiki-lazy] iterator) to a [`List`][concept-list].
+
+```kotlin
+// closed range
+1..5  // => 1..5
+(1..5).toList()  // => [1, 2, 3, 4, 5]
+
+// open range
+1..<5  // => 1..4
+(1..<5).toList()  // => [1, 2, 3, 4]
+```
+
+Note that the end limit is included in the range by default (a "closed" range).
+
+To get an "open" range, omitting the end limit, use `..<`.
+This more closely mimics some other languages such as Python.
+
+A `step` keyword can be included, but the `..` syntax only allows positive steps.
+Use `downTo` for descending sequences.
+
+```kotlin
+(1..5 step 2).toList()  // => [1, 3, 5]
+
+(5 downTo 1).toList()  // => [5, 4, 3, 2, 1]
+(5 downTo 1 step 2).toList()  // => [5, 3, 1]
+```
+
+[Characters][concept-chars] (not just ASCII) can be used instead of numbers:
+
+```kotlin
+('a'..'e').toList()  // => [a, b, c, d, e]
+
+// Devanagari
+('ऄ'..'ई').toList()  // => [ऄ, अ, आ, इ, ई]
+```
+
+~~~~exercism/note
+The output listed here after a `=>` was generated interactively by [Kotlin Notebook][notebook], which omits quotes from characters and strings (for readability).
+Assume that all the characters would be surrounded by `' '` in code.
+
+[notebook]: https://kotlinlang.org/docs/kotlin-notebook-overview.html
+~~~~
+
+[ref-range]: https://kotlinlang.org/docs/ranges.html#range
+[ref-range-lib]: https://kotlinlang.org/api/core/kotlin-stdlib/kotlin.ranges/
+[wiki-lazy]: https://en.wikipedia.org/wiki/Lazy_evaluation
+[concept-list]: https://exercism.org/tracks/kotlin/concepts/lists
+[concept-chars]: https://exercism.org/tracks/kotlin/concepts/chars

concepts/ranges/introduction.md

@@ -0,0 +1,47 @@
+# Introduction
+
+Suppose you want all the non-negative integers up to 1000.
+It would be ridiculous if you had to type all these into a list!
+
+Kotlin, like many languages, has a `Range` type to simplify this.
+
+Most simply, a range can be consecutive integers.
+To make clear what is included, most of the following examples convert the `Range` to a [`List`][concept-list].
+
+```kotlin
+// closed range
+1..5  // => 1..5
+(1..5).toList()  // => [1, 2, 3, 4, 5]
+
+// open range
+1..<5  // => 1..4
+(1..<5).toList()  // => [1, 2, 3, 4]
+```
+
+Note that the end limit is included in the range by default (a "closed" range).
+
+To get an "open" range, omitting the end limit, use `..<`.
+This more closely mimics some other languages such as Python.
+
+A `step` keyword can be included, but the `..` syntax only allows positive steps.
+Use `downTo` for descending sequences.
+
+```kotlin
+(1..5 step 2).toList()  // => [1, 3, 5]
+
+(5 downTo 1).toList()  // => [5, 4, 3, 2, 1]
+(5 downTo 1 step 2).toList()  // => [5, 3, 1]
+```
+
+[Characters][concept-chars] (not just ASCII) can be used instead of numbers:
+
+```kotlin
+('a'..'e').toList()  // => [a, b, c, d, e]
+
+// Devanagari
+('ऄ'..'ई').toList()  // => [ऄ, अ, आ, इ, ई]
+```
+
+[ref-range]: https://kotlinlang.org/docs/ranges.html#range
+[concept-list]: https://exercism.org/tracks/kotlin/concepts/lists
+[concept-chars]: https://exercism.org/tracks/kotlin/concepts/chars

concepts/ranges/links.json

@@ -0,0 +1,10 @@
+[
+  {
+    "url": "https://kotlinlang.org/docs/ranges.html#range",
+    "description": "Kotlin introduction to ranges."
+  },
+  {
+    "url": "https://kotlinlang.org/api/core/kotlin-stdlib/kotlin.ranges/",
+    "description": "Library reference for Range type."
+  }
+]

config.json

@@ -1387,6 +1387,11 @@
       "uuid": "168827c0-4867-449a-ad22-611c87314c48",
       "slug": "conditionals",
       "name": "Conditionals"
+    },
+    {
+      "uuid": "f0f07860-e8de-4ae5-b182-abc9c65b18ec",
+      "slug": "ranges",
+      "name": "Ranges"
     }
   ],
   "key_features": [