Infix functions in DSLs in Kotlin - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare an infix function named to.

Kotlin

infix fun String.[1](other: String): Pair<String, String> = Pair(this, other)

Drag options to blanks, or click blank then click option'

Afrom

Band

Cto

Dwith

Attempts:

3 left

💡 Hint

Common Mistakes

Using a function name that is not declared as infix.

Choosing a name that is not descriptive or conventional.

The infix function to allows you to write expressions like "a" to "b" to create pairs.

2fill in blank

medium

Complete the code to call the infix function to to create a pair.

Kotlin

val pair = "key" [1] "value"

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Ato

Bwith

Cfrom

Dand

Attempts:

3 left

💡 Hint

Common Mistakes

Using dot notation instead of infix call.

Using a wrong function name.

The infix function to is called without dots or parentheses, like "key" to "value".

3fill in blank

hard

Fix the error in the infix function declaration by completing the code.

Kotlin

infix fun [1].to(other: String): Pair<String, String> = Pair(this, other)

Drag options to blanks, or click blank then click option'

AInt

BAny

CPair

DString

Attempts:

3 left

💡 Hint

Common Mistakes

Using a wrong receiver type like Int or Pair.

Forgetting the receiver type.

The infix function to is declared as an extension on String to pair two strings.

4fill in blank

hard

Fill both blanks to create an infix function connect that joins two strings with a dash.

Kotlin

infix fun String.[1](other: String): String = this [2] "-" + other

Drag options to blanks, or click blank then click option'

Aconnect

B+

C*

Djoin

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong operator like * which is invalid for strings.

Choosing a function name that is not descriptive.

The infix function connect concatenates two strings with a dash using the + operator.

5fill in blank

hard

Fill all three blanks to create a DSL that uses infix functions to build a map.

Kotlin

val map = mapOf(
    "one" [1] 1,
    "two" [2] 2,
    "three" [3] 3
)

Drag options to blanks, or click blank then click option'

Ato

Bfrom

C->

Dwith

Attempts:

3 left

💡 Hint

Common Mistakes

Using operators like -> which is not an infix function here.

Mixing different infix functions in the same map.

The to infix function is used to create pairs inside mapOf to build a map.