Sync with the book project

Functional Programming/Member References/Exercise 1/src/Task.kt

@@ -24,7 +24,7 @@ fun List<Pet>.liveInWater(): List<Pet> =
 fun List<Pet>.areAmphibious(): List<Pet> =
   filter(AMPHIBIOUS::livesIn)
 
-fun List<Pet>.partAmphibious(): Pair<List<Pet>, List<Pet>> =
+fun List<Pet>.partitionAmphibious(): Pair<List<Pet>, List<Pet>> =
   partition(AMPHIBIOUS::livesIn)
 
 fun main() {
@@ -38,6 +38,6 @@ fun main() {
   pets.liveOnLand() eq "[Dog, Cat]"
   pets.liveInWater() eq "[Goldfish]"
   pets.areAmphibious() eq "[Turtle, Frog]"
-  pets.partAmphibious() eq
+  pets.partitionAmphibious() eq
     "([Turtle, Frog], [Dog, Cat, Goldfish])"
 }

Functional Programming/Member References/Exercise 1/task-info.yaml

@@ -12,7 +12,7 @@ files:
   - offset: 515
     length: 27
     placeholder_text: TODO()
-  - offset: 607
+  - offset: 612
     length: 30
     placeholder_text: TODO()
 - name: test/Tests.kt

Functional Programming/Member References/Exercise 1/task.md

@@ -10,5 +10,5 @@ The `main()` starter code creates a `List<Pet>`. Using `filter()` together with
 member references, implement three functions `liveOnLand()`, `liveInWater()`
 and `areAmphibious()` that discover which pets in the list live on land, in the
 water, or are amphibious. Lastly, use `partition()` to implement the
-`partAmphibious()` function that divides the pets into those that are
+`partitionAmphibious()` function that divides the pets into those that are
 amphibious and those that are not.

Functional Programming/Member References/Exercise 1/test/Tests.kt

@@ -86,7 +86,7 @@ class TestMemberReferencesExercise1 {
     ) {
         assertEquals(
                 expected = expected.let { (pos, neg) -> pos.toSet() to neg.toSet() },
-                actual = initial.partAmphibious().let { (pos, neg) -> pos.toSet() to neg.toSet() },
+                actual = initial.partitionAmphibious().let { (pos, neg) -> pos.toSet() to neg.toSet() },
                 message = "Wrong result for 'partAmphibious()' called on $initial:"
         )
     }

Functional Programming/Sequences/Exercise 7/task.md

@@ -4,7 +4,7 @@ Write a function `oddWithout1()` that creates an infinite sequence of odd
 numbers starting with `3` that do not contain the digit `1` in its decimal
 representation:
 
-```
+```text
 3, 5, 7, 9, 23, 25, 27, 29, 33 ...
 ```
 

Introduction to Objects/Constraining Visibility/Exercise 3/task.md

@@ -5,7 +5,7 @@ number. For `right()`, `left()`, `down()` and `up()`, a negative or zero
 `steps` argument should not update the location. Instead it should produce
 console output using this `String`:
 
-```
+```text
 "steps argument must be positive, is $steps"
 ```
 

Introduction to Objects/Constraining Visibility/Exercise 5/task.md

@@ -3,7 +3,7 @@
 IntelliJ IDEA allows you to extract repetitive code into a function. Select the
 following code in the body of the first function:
 
-```
+```text
 if (x <= 0) {
     println("Incorrect input: $x should be positive")
     return

Introduction to Objects/Creating Classes/Exercise 3/task.md

@@ -5,7 +5,7 @@ Create a `Robot` class with the following four member functions:
 `up(steps: Int)`. Each function should display one of the following
 phrases on the console:
 
-```
+```text
 Right N steps
 Left N steps
 Down N steps

Introduction to Objects/Exceptions/Exercise 1/task.md

@@ -3,7 +3,7 @@
 Display to the console all of the following `String`s that can't be converted to
 `Double` (that is, those where an attempt to convert it throws an exception):
 
-```
+```text
 "12", "1.2", "1,2", "1.2e0", "1.2e1",
 "1.2e2", "1.2e3", "1.2e10", "12.3e10",
 "1.2e-1", "1.2e-10".

Introduction to Objects/Objects Everywhere/Exercise 1/task.md

@@ -3,13 +3,13 @@
 Palindromes are words or phrases that read the same forward and backward. For
 example:
 
--   "mom" is a palindrome
+- "mom" is a palindrome
 
--   "dad" is a palindrome
+- "dad" is a palindrome
 
--   "rotator" is a palindrome
+- "rotator" is a palindrome
 
--   "streets" is *not* a palindrome
+- "streets" is *not* a palindrome
 
 Write a function that checks whether a word or phrase is a palindrome.
 

Introduction to Objects/Packages/Exercise 2/task.md

@@ -5,18 +5,18 @@ The starter code defines three packages `aaa`, `bbb` and `ccc` via the files
 
 In the first package `aaa`, define:
 
--   `val x = 10`
+- `val x = 10`
 
--   A top-level function `fa()` that takes an `Int` parameter and returns that
+- A top-level function `fa()` that takes an `Int` parameter and returns that
     argument multiplied by `x`
 
--   A class `K` with a `toString()` that returns `"K"`
+- A class `K` with a `toString()` that returns `"K"`
 
 In `package bbb`, `import` all the components from `aaa` and use them in a
 function `g()`, which takes an `Int` parameter `i` and returns the following
 `String` literal using members from `aaa`:
 
-```
+```text
 "${K()} ${fa(i)}"
 ```
 

Introduction to Objects/Properties/Exercise 2/task.md

@@ -4,7 +4,7 @@ A `Robot` object starts in the `(0, 0)` cell and can move right, left, up and
 down. Its location is stored as a pair of coordinates `(x, y)`, where `(0, 0)`
 is the top-left corner:
 
-```
+```text
 (x, y)
 (0, 0) (1, 0)
 (0, 1) (1, 1)

Introduction to Objects/Properties/Exercise 3/task.md

@@ -4,7 +4,7 @@ A `Robot` can move within a square field of size `100 x 100`. The borders of
 this field are "looped": if the robot is in cell `(0, 0)` and moves up one
 step, it arrives in cell `(0, 99)`.
 
-```
+```text
 (0, 0)
 // up(1)
 (0, 99)

Introduction to Objects/Summary 2/Exercise 4/task.md

@@ -2,7 +2,7 @@
 
 Create a `Dictionary` class that stores translations for words. It includes a
 member function `addTranslations(word: String, translations: String)`. The
-`translations` for `word` are delimited by whitespaces. If `word` is already
+`translations` for `word` are delimited by whitespace. If `word` is already
 present in the `Dictionary`, `addTranslations()` throws an
 `IllegalArgumentException` with the message
 `"Dictionary already has translations for '$word'"`.

Introduction to Objects/Summary 2/Exercise 7/task.md

@@ -18,10 +18,10 @@ the initial `number` equals the sum of the `remainder` and `result`.
 Store the Roman numerals in a mapping from `Int` to the associated `String`
 representation. For each pair `int = roman` starting from `1000 = M`:
 
--   Divide `remainder` into `int` to discover how many times you need to repeat
-    `roman` in the `result`.
+- Divide `remainder` into `int` to discover how many times you need to repeat
+  `roman` in the `result`.
 
--   Subtract the result from `remainder` to update it:
-    `remainder -= remainder / int`.
+- Subtract the result from `remainder` to update it:
+  `remainder -= remainder / int`.
 
 </div>

Introduction to Objects/Variable Argument Lists/Exercise 2/task.md

@@ -7,7 +7,7 @@ commas and surrounded by square brackets.
 
 For example, the output for `printArgs("Numbers: ", 1, 2, 3)` should be:
 
-```
+```text
 Numbers: [1, 2, 3]
 ```
 

Object-Oriented Programming/Inner Classes/Exercise 1/src/Task.kt

@@ -6,7 +6,7 @@ fun interface Pet {
   fun speak(): String
 }
 
-class PetCreator {
+object CreatePet {
   fun home() = " home!"
   fun dog(): Pet {
     val say = "Bark"
@@ -32,9 +32,8 @@ class PetCreator {
 }
 
 fun main() {
-  val create = PetCreator()
-  create.dog().speak() eq "Bark home!"
-  create.cat().speak() eq "Meow home!"
-  create.hamster().speak() eq "Squeak home!"
-  create.goldfish().speak() eq "Blub home!"
+  CreatePet.dog().speak() eq "Bark home!"
+  CreatePet.cat().speak() eq "Meow home!"
+  CreatePet.hamster().speak() eq "Squeak home!"
+  CreatePet.goldfish().speak() eq "Blub home!"
 }

Object-Oriented Programming/Inner Classes/Exercise 1/task-info.yaml

@@ -4,7 +4,7 @@ files:
   visible: true
   placeholders:
   - offset: 80
-    length: 722
+    length: 706
     placeholder_text: // TODO
 - name: test/Tests.kt
   visible: false

Object-Oriented Programming/Type Checking/Exercise 2/src/TaskB.kt

@@ -5,7 +5,7 @@ import typechecking.name
 
 interface BeverageContainer {
   fun open(): String
-  fun pour() = "${this.name}: Pour"
+  fun pour() = "$name: Pour"
   fun recycle(): String
 }
 

Object-Oriented Programming/Type Checking/Exercise 2/task-info.yaml

@@ -12,5 +12,5 @@ files:
   visible: true
   placeholders:
   - offset: 116
-    length: 1239
+    length: 1232
     placeholder_text: // TODO

Power Tools/Creating Generics/Exercise 1/task.md

@@ -2,7 +2,7 @@
 
 Create a generic interface called `Items` with a single function `next()` that
 returns an object of the generic type, or `null`. Make `Items` usable for [SAM
-conversions](https://stepik.org/lesson/350600/step/1).
+conversions].
 
 Create a generic function called `itemIter()` that takes a `vararg items` of the
 type parameter and returns an `Items` object produced with a SAM conversion. The

Preventing Failure/Check Instructions/Exercise 3/task.md

@@ -1,7 +1,7 @@
 ## Check Instructions (#3)
 
 This exercise further explores ranges, introduced in [Looping &
-Ranges](https://stepik.org/lesson/104311/step/1), and shows how they can be used with check
+Ranges], and shows how they can be used with check
 instructions.
 
 Create a class `Level` with two constructor arguments: `val range: IntRange`,

Preventing Failure/The Nothing Type/Exercise 1/task.md

@@ -5,7 +5,7 @@ and passes it to the base-class constructor. Write a function `fail(msg:
 String)` that passes `msg` to `trace()`, and then throws a `Failure(msg)`.
 
 Now write your own versions of `require()` and `check()` (from [Check
-Instructions](https://stepik.org/lesson/350665/step/1)) that use `fail()`. The starter code in
+Instructions]) that use `fail()`. The starter code in
 `main()` tests your functions.
 
 <sub> This task doesn't contain automatic tests,

Programming Basics/Booleans/Exercise 2/task.md

@@ -7,7 +7,7 @@ Write a similar function for `showOr()`.
 
 The sample output for `showAnd(true, true)` should be:
 
-```
+```text
 true && true == true
 ```
 

Programming Basics/Booleans/Exercise 4/src/Foo.kt

@@ -1,3 +1,4 @@
+// Booleans/Foo.kt
 package booleansExercise4
 
 fun foo(): Boolean = true

Programming Basics/Expressions & Statements/Exercise 2/task.md

@@ -2,11 +2,11 @@
 
 Write three functions using expression body syntax:
 
--   `f()` takes two `Int` parameters and returns the sum.
+- `f()` takes two `Int` parameters and returns the sum.
 
--   `g()` takes two `String` parameters and returns them, concatenated.
+- `g()` takes two `String` parameters and returns them, concatenated.
 
--   `h()` calls `println()` to display `"h()"`.
+- `h()` calls `println()` to display `"h()"`.
 
 In `main()`, assign the result of each function to a `val`, and specify the
 type. Then display on the console the types of all the functions `f()`, `g()`

Programming Basics/Hello, World/Exercise 2/task.md

@@ -3,7 +3,7 @@
 Display "Hello, Kotlin!" on the console, but with "Kotlin" appearing on the
 next line. You can display two separate `String`s to achieve this:
 
-```
+```text
 Hello,
 Kotlin!
 ```

Programming Basics/Looping & Ranges/Exercise 4/src/Task.kt

@@ -1,7 +1,7 @@
 // LoopingAndRanges/Task4.kt
 package loopingAndRangesExercise4
 
-fun printHalfPyramid(n: Int) {
+fun showHalfTriangle(n: Int) {
   for (i in 1..n) {
     repeat(i) {
       print("#")
@@ -11,7 +11,7 @@ fun printHalfPyramid(n: Int) {
 }
 
 fun main() {
-  printHalfPyramid(4)
+  showHalfTriangle(4)
 }
 /* Output:
 #

Programming Basics/Looping & Ranges/Exercise 4/task.md

@@ -1,9 +1,9 @@
 ## Looping & Ranges (#4)
 
 Display half of a triangle. For an argument of 6 the function
-`printHalfPyramid()` should display the following:
+`showHalfTriangle()` should display the following:
 
-```
+```text
 #
 ##
 ###

Programming Basics/Looping & Ranges/Exercise 4/test/Tests.kt

@@ -12,7 +12,7 @@ class TestLoopingAndRangesExercise4 {
     runAndCheckSystemOutput(
       "Incorrect output for n = $n:",
       expected) {
-      printHalfPyramid(n)
+      showHalfTriangle(n)
     }
   }
 

Programming Basics/Looping & Ranges/Exercise 5/task.md

@@ -7,7 +7,7 @@ expands into a `for` expression. You type the expression you want to iterate
 over, along with the name for the index variable. IntelliJ IDEA automatically
 suggests the variable name to iterate over if it's available in the context.
 
-```
+```text
 iter + tab
 
 for (i in iterable) {

Programming Basics/Number Types/Exercise 2/task.md

@@ -2,7 +2,7 @@
 
 Check which of the following values can't be stored in an `Int` type:
 
-- A million (10<sup>6</sup>)
-- A billion (10<sup>9</sup>)
-- A trillion (10<sup>12</sup>)
-- A quintillion (10<sup>18</sup>)
+- A million (10^6^)
+- A billion (10^9^)
+- A trillion (10^12^)
+- A quintillion (10^18^)

Programming Basics/Repetition with while/Exercise 5/task.md

@@ -4,11 +4,11 @@ IntelliJ IDEA can extract a `val` or `var` automatically. Select the expression
 `getFooResult()` inside a string template, then do one of the following:
 
 - Invoke <span class="control">`Find action`</span> (by pressing <span class="shortcut">&shortcut:GotoAction;</span>),
-then type `Introduce variable` to find the corresponding action
+then type `Extract variable` to find the corresponding action
 
 - Press <span class="shortcut">&shortcut:IntroduceVariable;</span>;
 
-- Choose <span class="control">`Refactor | Extract/Introduce | Variable...`</span>
+- Choose <span class="control">`Refactor | Extract | Variable...`</span>
 in the application menu.
 
 Type the name of the new variable. IntelliJ IDEA tries to suggest a name

Programming Basics/String Templates/Exercise 3/task.md

@@ -8,7 +8,7 @@ and the `Char` value with single quotes.
 
 Sample output:
 
-```
+```text
 i: 10
 s: "abc"
 c: 'a'

Programming Basics/Summary 1/Exercise 10/task.md

@@ -4,7 +4,7 @@ Create a function `showSnake(rows: Int, columns: Int)` that displays a table
 filled with sequential numbers in a form of snake. For example, `showSnake(3,
 3)` should produce the following:
 
-```
+```text
  0 1 2
  5 4 3
  6 7 8
@@ -19,6 +19,6 @@ It depends on the biggest number, the last one: put exactly one space before it.
 
 Use the string `"%${width}d".format(value)`, where the `width` variable stores
 the width of each number cell, to format the value based on the actual input
-(`rows` and `columns`). 
+(`rows` and `columns`).
 
 </div>

Programming Basics/Summary 1/Exercise 9/task.md

@@ -3,7 +3,7 @@
 Display a triangle. For n = 6 the function `showTriangle()` should produce the
 following:
 
-```
+```text
      #
     ###
    #####

Usability/Data Classes/Exercise 1/task.md

@@ -2,12 +2,12 @@
 
 Create a `data` class called `AirlineTicket` containing the following fields:
 
--   `firstName: String`
+- `firstName: String`
 
--   `lastName: String`
+- `lastName: String`
 
--   `ticket: Int`
+- `ticket: Int`
 
--   `origin: String`
+- `origin: String`
 
--   `destination: String`
+- `destination: String`

Usability/Data Classes/Exercise 3/src/Task.kt

@@ -6,7 +6,7 @@ data class Book(val title: String, val authors: List<Author>)
 
 data class Author(val name: String)
 
-fun authorBooksMap(books: List<Book>): Map<Author, List<Book>> {
+fun createAuthorToBooksMap(books: List<Book>): Map<Author, List<Book>> {
   val result = mutableMapOf<Author, MutableList<Book>>()
   for (book in books) {
     for (author in book.authors) {
@@ -34,7 +34,7 @@ fun main() {
     Book("Kotlin in Action", listOf(Author("Dmitry Jemerov"), Author("Svetlana Isakova"))),
     Book("Atomic Kotlin", listOf(Author("Bruce Eckel"), Author("Svetlana Isakova")))
   )
-  val authorToBooksMap = authorBooksMap(books)
+  val authorToBooksMap = createAuthorToBooksMap(books)
   authorToBooksMap.getValue(Author("Bruce Eckel")).size eq 11
   authorToBooksMap.getValue(Author("Svetlana Isakova")).first().title eq "Kotlin in Action"
 }

Usability/Data Classes/Exercise 3/task-info.yaml

@@ -3,7 +3,7 @@ files:
 - name: src/Task.kt
   visible: true
   placeholders:
-  - offset: 242
+  - offset: 250
     length: 267
     placeholder_text: TODO()
 - name: test/Tests.kt

Usability/Data Classes/Exercise 3/task.md

@@ -1,6 +1,6 @@
 ## Data Classes (#3)
 
 The starter code contains definitions for the `data` classes `Author` and
-`Book`. Write a function called `authorBooksMap()` that takes a `List`
+`Book`. Write a function called `createAuthorToBooksMap()` that takes a `List`
 of books as its parameter. It builds and returns a `Map` with `Author` as the
 key that maps to the `List<Book>` written by that author.

Usability/Data Classes/Exercise 3/test/Tests.kt

@@ -14,7 +14,7 @@ class TestDataClassesExercise3 {
     val list = listOf(book)
     Assert.assertEquals("Wrong result for $list:",
       mapOf(Author("Author") to listOf(book)),
-      authorBooksMap(list))
+      createAuthorToBooksMap(list))
   }
 
   @Test(timeout = TIMEOUT)
@@ -24,7 +24,7 @@ class TestDataClassesExercise3 {
     Assert.assertEquals("Wrong result for $list:",
       mapOf(Author("first author") to listOf(book),
         Author("second author") to listOf(book)),
-      authorBooksMap(list))
+      createAuthorToBooksMap(list))
   }
 
   @Test(timeout = TIMEOUT)
@@ -33,7 +33,7 @@ class TestDataClassesExercise3 {
       Book("second Book", listOf(Author("Author"))))
     Assert.assertEquals("Wrong result for $list:",
       mapOf(Author("Author") to list),
-      authorBooksMap(list))
+      createAuthorToBooksMap(list))
   }
 
   @Test(timeout = TIMEOUT)
@@ -76,7 +76,7 @@ class TestDataClassesExercise3 {
       dmitry to listOf(kotlinInAction),
       svetlana to listOf(kotlinInAction, atomicKotlin)
     )
-    val actual = authorBooksMap(books)
+    val actual = createAuthorToBooksMap(books)
     Assert.assertEquals("Wrong result for sample:", expected, actual)
   }
 }

Usability/Enumerations/Exercise 1/task.md

@@ -8,7 +8,7 @@ movement.
 The location is stored as a pair of coordinates `(x, y)`, where `(0, 0)` is the
 top-left corner:
 
-```
+```text
 (x, y)
 (0, 0) (1, 0)
 (0, 1) (1, 1)

Usability/Named & Default Arguments/Exercise 3/task.md

@@ -3,7 +3,7 @@
 Implement a `joinComments()` function which takes a `String` parameter
 containing comment text. `joinComments()` joins the lines of the comment text,
 removing newlines and using a default of `;` as the line separator. It removes
-the comment slashes along with any whitespace after the slashes (`// `).
+the comment slashes along with any whitespace after the slashes (`//`).
 
 <div class="hint">
 

Usability/Overloading/Exercise 1/task.md

@@ -2,7 +2,7 @@
 
 Create a class called `Dog` with an overloaded `bark()` member function:
 
--   `bark(n: Int)` displays `woof` repeated `n` times to the console.
+- `bark(n: Int)` displays `woof` repeated `n` times to the console.
 
--   `bark(n: Int, say: String)` displays the contents of `say` repeated `n` times
-    to the console.
+- `bark(n: Int, say: String)` displays the contents of `say` repeated `n` times
+  to the console.

Usability/when Expressions/Exercise 3/src/Task.kt

@@ -11,7 +11,7 @@ fun balanced(input: String): Boolean {
       ' ' -> {
       }
       else -> throw IllegalArgumentException("The string must consist " +
-        "only of parentheses and whitespaces")
+        "only of parentheses and whitespace")
     }
     if (leftUnmatched < 0) return false
   }