BuildBlock for combining results in Swift

Introduction

BuildBlock helps you combine multiple pieces of work that can succeed or fail into one result. It makes it easy to handle many results together.

When you want to run several tasks and collect all their success or failure results.

When you need to combine multiple validation checks into one overall result.

When you want to merge several small results into a bigger result in a clear way.

Syntax

Swift

func buildBlock(_ components: Result<Void, Error>...) -> Result<Void, Error> {
    for component in components {
        if case .failure(let error) = component {
            return .failure(error)
        }
    }
    return .success(())
}

This example shows a buildBlock function that combines multiple Result values.

If any component is a failure, it returns that failure immediately.

Examples

This combines two results. Since one is failure, combined is failure.

Swift

enum MyError: Error {
    case example
}

let result1: Result<Void, Error> = .success(())
let result2: Result<Void, Error> = .failure(MyError.example)

let combined = buildBlock(result1, result2)

Both results are success, so combined is success.

Swift

let result1: Result<Void, Error> = .success(())
let result2: Result<Void, Error> = .success(())

let combined = buildBlock(result1, result2)

Sample Program

This program defines a buildBlock function to combine multiple Result values. It prints whether the combined results are success or failure.

Swift

import Foundation

enum MyError: Error {
    case example
}

func buildBlock(_ components: Result<Void, Error>...) -> Result<Void, Error> {
    for component in components {
        if case .failure(let error) = component {
            return .failure(error)
        }
    }
    return .success(())
}

let successResult: Result<Void, Error> = .success(())
let failureResult: Result<Void, Error> = .failure(MyError.example)

let combined1 = buildBlock(successResult, successResult)
let combined2 = buildBlock(successResult, failureResult)

switch combined1 {
case .success:
    print("combined1: Success")
case .failure:
    print("combined1: Failure")
}

switch combined2 {
case .success:
    print("combined2: Success")
case .failure:
    print("combined2: Failure")
}

Important Notes

BuildBlock is useful in SwiftUI and result builders to combine multiple parts.

Here, it stops at the first failure to avoid unnecessary work.

Summary

BuildBlock combines multiple Result values into one.

It returns failure if any component fails, otherwise success.

This helps manage multiple results cleanly and clearly.