berikv/FailableSequence

Installation

For a Swift Package

Edit the Package.swift file. Add the FailableSequence as a dependency:

let package = Package(
    name: " ... ",
    products: [ ... ],
    dependencies: [
        .package(url: "https://github.com/berikv/FailableSequence.git", from: "0.0.2") // here
    ],
    targets: [
        .target(
            name: " ... ",
            dependencies: [
                "FailableSequence" // and here
            ]),
    ]
)

For .xcodeproj projects

1. Open menu File > Add Packages...
2. Search for "https://github.com/berikv/FailableSequence.git" and click Add Package.
3. Open your project file, select your target in "Targets".
4. Open Dependencies
5. Click the + sign
6. Add FailableSequence

Usage

Create a failable sequence using a first and next().

let sequence = failableSequence(first: 0) { number in
    let next = number + 1
    if next == 3 { throw NumberIsThreeError() }
    return next
}

var numbers = [Int]()
var theError: Error?

do {
    try sequence.forEach { numbers.append($0) }
} catch {
    theError = error
}

// numbers == [0, 1]
// error is NumberIsThreeError

Create a lazy failable map from another sequence.

let sequence = (0..<4).failableMap { number -> Int in
    let next = number + 1
    if next == 3 { throw NumberIsThreeError() }
    return next
}

var numbers = [Int]()
var theError: Error?

do {
    try sequence.forEach { numbers.append($0) }
} catch {
    theError = error
}

// numbers == [1, 2]
// error is NumberIsThreeError

Create an Array from a FailableSequence.

// Note, if this sequence would cause the *Array init* to throw an error if number == 3.
let sequence = failableSequence(first: 0) { number in
    let next = number + 1
    if next == 3 { throw NumberIsThreeError() }
    return next
}

let array = try Array(sequence.prefix(2))
// array == [0, 1]

Note that throwing an error will not end the sequence.

let sequence = (0...4).failableMap { number -> Int in
    let next = number + 1
    if next == 3 { throw NumberIsThreeError() }
    return next
}

let array = Array(sequence.skipOnThrowSequence)
// array == [1, 2, 4, 5]

Contributing

Make sure your code is well tested. Run ./coverage.sh for an overiew.

License

Licensed under MIT. See the license.md

Package Metadata

Repository: berikv/FailableSequence

Stars: 0

Forks: 0

Open issues: 0

Default branch: main

Primary language: swift

License: MIT

README: Readme.md