Custom result builder declaration in Swift - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a custom result builder named Builder.

Swift

resultBuilder [1] Builder {
    static func buildBlock(_ components: String...) -> String {
        components.joined(separator: ", ")
    }
}

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

A@

Bclass

Cstruct

Denum

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting the '@' symbol before 'resultBuilder'.

Using 'struct' or 'class' instead of '@resultBuilder'.

In Swift, a custom result builder is declared using the '@resultBuilder' attribute before the builder's name.

2fill in blank

medium

Complete the code to define the buildBlock method that combines components into a single string.

Swift

static func buildBlock(_ components: [1]) -> String {
    components.joined(separator: ", ")
}

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AString

BInt

C[String]

DString...

Attempts:

3 left

💡 Hint

Common Mistakes

Using '[String]' instead of 'String...'.

Using a single 'String' instead of variadic.

The buildBlock method takes a variadic parameter of type String, written as 'String...'.

3fill in blank

hard

Fix the error in the buildIf method to correctly handle optional components.

Swift

static func buildIf(_ component: [1]) -> String {
    component ?? ""
}

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AString?

BString

COptional<String>

DInt?

Attempts:

3 left

💡 Hint

Common Mistakes

Using non-optional 'String' instead of 'String?'.

Using 'Int?' which is unrelated.

The buildIf method takes an optional String parameter, written as 'String?'.

4fill in blank

hard

Fill both blanks to define a buildEither method for the first case in the result builder.

Swift

static func buildEither(first component: [1]) -> String {
    [2]
}

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AString

Bcomponent

CString?

Dreturn component

Attempts:

3 left

💡 Hint

Common Mistakes

Using optional type 'String?' instead of 'String'.

Omitting the 'return' keyword.

The buildEither method takes a String and returns it using 'return component'.

5fill in blank

hard

Fill all three blanks to define a buildArray method that combines an array of components.

Swift

static func buildArray(_ components: [[1]]) -> [2] {
    components.[3](separator: ", ")
}

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AString

Cjoined

Djoined(separator:)

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect types for the array or return type.

Using 'joined(separator:)' as a method name instead of 'joined'.

The buildArray method takes an array of Strings and returns a String by joining components with ', '.