Swift

https://www.swift.org/documentation
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### Install Swift Concurrency Skill

Source: https://www.swift.org/documentation/articles/getting-started-with-cursor-swift.html

Example command to install the Swift Concurrency agent skill. This command specifies the repository and the name of the skill to be added.

```bash
npx skills     add https://github.com/avdlee/swift-concurrency-agent-skill     --skill swift-concurrency
```

--------------------------------

### Example Program Using AsyncHTTPClient

Source: https://www.swift.org/documentation/server/guides/allocations.html

An example Swift program that performs ten HTTP GET requests using AsyncHTTPClient. It demonstrates setting up the client, handling requests sequentially, and managing event loops and promises.

```swift
import AsyncHTTPClient
import NIO
import Logging

let urls = Array(repeating:"http://httpbin.org/get", count: 10)
var logger = Logger(label: "ahc-alloc-demo")

logger.info("running HTTP requests", metadata: ["count": "\(urls.count)"])
MultiThreadedEventLoopGroup.withCurrentThreadAsEventLoop { eventLoop in
    let httpClient = HTTPClient(eventLoopGroupProvider: .shared(eventLoop),
                                backgroundActivityLogger: logger)

    func doRemainingRequests(_ remaining: ArraySlice<String>,
                             overallResult: EventLoopPromise<Void>,
                             eventLoop: EventLoop) {
        var remaining = remaining
        if let first = remaining.popFirst() {
            httpClient.get(url: first, logger: logger).map { [remaining] _ in
                eventLoop.execute { // for shorter stacks
                    doRemainingRequests(remaining, overallResult: overallResult, eventLoop: eventLoop)
                }
            }.whenFailure { error in
                overallResult.fail(error)
            }
        } else {
            return overallResult.succeed(())
        }
    }

    let promise = eventLoop.makePromise(of: Void.self)
    // Kick off the process
    doRemainingRequests(urls[...],
                        overallResult: promise,
                        eventLoop: eventLoop)

    promise.futureResult.whenComplete { result in
        switch result {
        case .success:
            logger.info("all HTTP requests succeeded")
        case .failure(let error):
            logger.error("HTTP request failure", metadata: ["error": "\(error)"])
        }

        httpClient.shutdown { maybeError in
            if let error = maybeError {
                logger.error("AHC shutdown failed", metadata: ["error": "\(error)"])
            }
            eventLoop.shutdownGracefully { maybeError in
                if let error = maybeError {
                    logger.error("EventLoop shutdown failed", metadata: ["error": "\(error)"])
                }
            }
        }
    }
}

logger.info("exiting")

```

--------------------------------

### Install Swift SDK for Android

Source: https://www.swift.org/documentation/articles/swift-sdk-for-android-getting-started.html

Downloads and installs the Swift SDK bundle for Android using the `swift sdk install` command. Requires a URL to the artifact bundle and its checksum.

```bash
$ swift sdk install https://download.swift.org/swift-6.3.2-release/android-sdk/swift-6.3.2-RELEASE/swift-6.3.2-RELEASE_android.artifactbundle.tar.gz --checksum 939e933549d12d28f2e0bf71019d734d309859e9773c572657ce565a81f85d68

```

--------------------------------

### List Installed Swift SDKs

Source: https://www.swift.org/documentation/articles/swift-sdk-for-android-getting-started.html

Lists all installed Swift SDKs, including the newly installed Android SDK. This command helps verify the installation.

```bash
$ swift sdk list
swift-6.3.2-RELEASE_android

```

--------------------------------

### Install Swift SDK for WebAssembly

Source: https://www.swift.org/documentation/articles/wasm-getting-started.html

Use this command to install the Swift SDKs for WebAssembly. Ensure you have the correct Swift toolchain version selected.

```bash
swift sdk install https://download.swift.org/swift-6.3.2-release/wasm-sdk/swift-6.3.2-RELEASE/swift-6.3.2-RELEASE_wasm.artifactbundle.tar.gz --checksum a61f0584c93283589f8b2f42db05c1f9a182b506c2957271402992655591dd7c
```

--------------------------------

### Install Docker on Amazon Linux 2

Source: https://www.swift.org/documentation/server/guides/deploying/aws.html

Installs Docker and git on an Amazon Linux 2 instance and starts the Docker service. This is a prerequisite for compiling Swift code within a Docker container.

```bash
sudo yum install docker git
sudo usermod -a -G docker ec2-user
sudo systemctl start docker

```

--------------------------------

### Install Valgrind on Ubuntu

Source: https://www.swift.org/documentation/server/guides/memory-leaks-and-usage.html

Use this command to install Valgrind on Ubuntu systems via apt-get.

```bash
sudo apt-get install valgrind
```

--------------------------------

### List Installed SDKs

Source: https://www.swift.org/documentation/articles/static-linux-getting-started.html

Lists all currently installed Static Linux SDKs on the system.

```bash
$ swift sdk list

```

--------------------------------

### Install Static Linux SDK

Source: https://www.swift.org/documentation/articles/static-linux-getting-started.html

Installs the Static Linux SDK from a URL or local file. Use the --checksum option for remote URLs to verify the archive's integrity.

```bash
$ swift sdk install <URL-or-filename-here> [--checksum <checksum-for-archive-URL>]

```

```bash
$ swift sdk install https://download.swift.org/swift-6.3.2-release/static-sdk/swift-6.3.2-RELEASE/swift-6.3.2-RELEASE_static-linux-0.1.0.artifactbundle.tar.gz --checksum 3fd798bef6f4408f1ea5a6f94ce4d4052830c4326ab85ebc04f983f01b3da407

```

--------------------------------

### Install Neovim using Snap

Source: https://www.swift.org/documentation/articles/zero-to-swift-nvim.html

Installs Neovim using the snap package manager. This is recommended for systems where the default repository version is outdated.

```bash
 $  sudo snap install nvim --classic
 $  nvim --version
NVIM v0.11.5
Build type: RelWithDebInfo
LuaJIT 2.1.1741730670
Run "nvim -V1 -v" for more info

```

--------------------------------

### Install perf on Ubuntu

Source: https://www.swift.org/documentation/server/guides/linux-perf.html

Installs the generic Linux perf tools package on Ubuntu systems.

```bash
apt-get update && apt-get -y install linux-tools-generic

```

--------------------------------

### Deploy the SAM project

Source: https://www.swift.org/documentation/server/guides/deploying/aws-sam-lambda.html

Deploys your SAM project to AWS, creating Lambda functions, API Gateway, and DynamoDB. Use --guided for interactive setup.

```bash
sam deploy --guided

```

--------------------------------

### Clone Swift NIO Example Project

Source: https://www.swift.org/documentation/server/guides/deploying/heroku.html

Clones the Swift NIO example project from GitHub to your local machine.

```bash
git clone https://github.com/apple/swift-nio
```

--------------------------------

### Initialize lazy.nvim Setup

Source: https://www.swift.org/documentation/articles/zero-to-swift-nvim.html

Initializes lazy.nvim and specifies the directory where plugin specifications can be found. Ensure the 'plugins' directory exists.

```lua
require("lazy").setup("plugins")
```

--------------------------------

### Install Latest Swift Toolchain with Swiftly

Source: https://www.swift.org/documentation/articles/swift-sdk-for-android-getting-started.html

Installs the latest stable Swift release toolchain using the `swiftly` command-line tool. This is the recommended method for managing host toolchains on macOS and Linux.

```bash
$ swiftly install latest
Fetching the latest stable Swift release...
Installing Swift 6.3.2

Installing package in user home directory...
Swift 6.3.2 is installed successfully!
$ swiftly use latest
The global default toolchain has been set to `Swift 6.3.2`

$ swift --version
Apple Swift version 6.3.2 (swift-6.3.2-RELEASE)
Target: arm64-apple-macosx26.0

```

--------------------------------

### Install perf on Fedora/RedHat

Source: https://www.swift.org/documentation/server/guides/linux-perf.html

Installs the perf package on Fedora and RedHat-based systems.

```bash
yum install -y perf

```

--------------------------------

### Verify perf installation

Source: https://www.swift.org/documentation/server/guides/linux-perf.html

Runs a basic perf stat command to verify the installation. Requires root privileges or sudo.

```bash
sudo perf stat -- sleep 0.1

```

--------------------------------

### Example MongoDB Connection String

Source: https://www.swift.org/documentation/server/guides/deploying/aws-copilot-fargate-vapor-mongo.html

This is an example format for a MongoDB Atlas connection string. Replace placeholders with your actual credentials.

```text
mongodb+srv://username:<password>@mycluster.mongodb.net/?retryWrites=true&w=majority

```

--------------------------------

### Install perf on Debian

Source: https://www.swift.org/documentation/server/guides/linux-perf.html

Installs the Linux perf package on Debian systems.

```bash
apt-get update && apt-get -y install linux-perf

```

--------------------------------

### Configure LuaSnip Plugin

Source: https://www.swift.org/documentation/articles/zero-to-swift-nvim.html

Sets up LuaSnip and loads snippets from the 'snippets' directory. Ensure LuaSnip is installed as a plugin.

```lua
-- lua/plugins/snippets.lua
return {
    {
        'L3MON4D3/LuaSnip',
        conifg = function(opts)
            require('luasnip').setup(opts)
            require('luasnip.loaders.from_snipmate').load({ paths = "./snippets" })
        end,
    },
}

```

--------------------------------

### Structured Logging Example with Metadata

Source: https://www.swift.org/documentation/server/guides/libraries/log-levels.html

Demonstrates structured logging by passing dynamic information as metadata key-value pairs, making logs easier to parse.

```swift
log.info("Accepted connection", metadata: [
  "connection.id": "\(connection.id)",
  "connection.peer": "\(connection.peer)",
  "connections.total": "\(connections.count)"
])

// example output:
// <date> info [connection.id:?,connection.peer:?, connections.total:?] Accepted connection

```

--------------------------------

### Install and configure swift-mode package

Source: https://www.swift.org/documentation/articles/zero-to-swift-emacs.html

Installs the `swift-mode` package and associates it with `.swift` files and the `swift` interpreter. This provides basic editing support for Swift code.

```emacs-lisp
;; Swift editing support
(use-package swift-mode
    :ensure t
    :mode "\.swift\'"
    :interpreter "swift")

```

--------------------------------

### Factory Method Naming Convention

Source: https://www.swift.org/documentation/api-design-guidelines

Begin names of factory methods with 'make'. This example demonstrates the correct convention for creating new instances.

```swift
x.makeIterator()
```

--------------------------------

### Create Procfile for Vapor App

Source: https://www.swift.org/documentation/server/guides/deploying/heroku.html

Example Procfile content for a Vapor application, specifying production environment, hostname, and port.

```bash
web: Run serve --env production --hostname 0.0.0.0 --port $PORT
```

--------------------------------

### Install and configure lsp-mode for language server integration

Source: https://www.swift.org/documentation/articles/zero-to-swift-emacs.html

Installs the `lsp-mode` package and sets up hooks for Swift mode. This enables integration with language servers like `sourcekit-lsp` for advanced features.

```emacs-lisp
;; Used to interface with swift-lsp.
(use-package lsp-mode
    :ensure t
    :commands lsp
    :hook ((swift-mode . lsp)))

```

--------------------------------

### Install and configure powerline for status bar

Source: https://www.swift.org/documentation/articles/zero-to-swift-emacs.html

Installs the `powerline` package and sets it to use the default theme. Powerline provides a sophisticated status line for Emacs.

```emacs-lisp
;; Powerline
(use-package powerline
  :ensure t
  :config
  (powerline-default-theme))

```

--------------------------------

### Install binutils on Linux

Source: https://www.swift.org/documentation/server/guides/memory-leaks-and-usage.html

Install the binutils package on a Linux system, which provides tools like addr2line for symbolication. This command is typically run with sudo.

```bash
sudo apt install binutils
```

--------------------------------

### Install and configure company mode for completion

Source: https://www.swift.org/documentation/articles/zero-to-swift-emacs.html

Installs the `company` package and enables global company mode. This provides an extensible, real-time code completion framework.

```emacs-lisp
;; Company mode (completion)
(use-package company
    :ensure t
    :config
    (global-company-mode +1))

```

--------------------------------

### Install heaptrack on Ubuntu

Source: https://www.swift.org/documentation/server/guides/memory-leaks-and-usage.html

Install the heaptrack tool on Ubuntu systems to profile heap memory usage and analyze memory leaks. This command is typically run with sudo.

```bash
sudo apt-get install heaptrack
```

--------------------------------

### Download and Configure Android NDK on Linux

Source: https://www.swift.org/documentation/articles/swift-sdk-for-android-getting-started.html

Automates the download, extraction, and configuration of the Android NDK for Linux. It sets the `ANDROID_NDK_HOME` environment variable and runs the setup script.

```bash
$ cd ~/.swiftpm/swift-sdks/swift-6.3.2-RELEASE_android.artifactbundle/swift-android/
$ curl -fSL -o ndk.zip https://dl.google.com/android/repository/android-ndk-r27d-$(uname -s).zip
$ unzip -qo ndk.zip
$ export ANDROID_NDK_HOME=$PWD/android-ndk-r27d
$ ./scripts/setup-android-sdk.sh

```

--------------------------------

### Install nvim-cmp with lazy.nvim

Source: https://www.swift.org/documentation/articles/zero-to-swift-nvim.html

This snippet tells lazy.nvim to download and lazily load the nvim-cmp plugin when entering insert mode.

```lua
-- lua/plugins/codecompletion.lua
return {
    {
        "hrsh7th/nvim-cmp",
        version = false,
        event = "InsertEnter",
    },
}

```

--------------------------------

### Download and Configure Android NDK on macOS

Source: https://www.swift.org/documentation/articles/swift-sdk-for-android-getting-started.html

Automates the download, extraction, and configuration of the Android NDK for macOS. It sets the `ANDROID_NDK_HOME` environment variable and runs the setup script.

```bash
$ cd ~/Library/org.swift.swiftpm/swift-sdks/swift-6.3.2-RELEASE_android.artifactbundle/swift-android/
$ curl -fSL -o ndk.zip https://dl.google.com/android/repository/android-ndk-r27d-$(uname -s).zip
$ unzip -qo ndk.zip
$ export ANDROID_NDK_HOME=$PWD/android-ndk-r27d
$ ./scripts/setup-android-sdk.sh

```

--------------------------------

### Initialize AWS Copilot Application

Source: https://www.swift.org/documentation/server/guides/deploying/aws-copilot-fargate-vapor-mongo.html

Use this command to start a new AWS Copilot application. This sets up the basic structure for your project on AWS.

```bash
copilot app init todo

```

--------------------------------

### Create Neovim Configuration Directory and init.lua

Source: https://www.swift.org/documentation/articles/zero-to-swift-nvim.html

Sets up the necessary directory structure for Neovim's Lua configuration and creates the main init.lua file.

```bash
 $  mkdir -p ~/.config/nvim/lua && cd ~/.config/nvim
 $  nvim init.lua

```

--------------------------------

### Initializer and Factory Method Naming

Source: https://www.swift.org/documentation/api-design-guidelines

The first argument to initializer and factory methods should not form a phrase starting with the base name. These examples show correct and incorrect ways to name such calls.

```swift
let foreground = Color(red: 32, green: 64, blue: 128)
let newPart = factory.makeWidget(gears: 42, spindles: 14)
let ref = Link(target: destination)
```

```swift
let foreground = Color(havingRGBValuesRed: 32, green: 64, andBlue: 128)
let newPart = factory.makeWidget(havingGearCount: 42, andSpindleCount: 14)
let ref = Link(to: destination)
```

--------------------------------

### Argument Labels for Prepositional Phrases

Source: https://www.swift.org/documentation/api-design-guidelines

Demonstrates using argument labels that start at the preposition when the first argument forms part of a prepositional phrase.

```swift
a.move("toX": b, "y": c)
a.fade("fromRed": b, "green": c, "blue": d)
```

--------------------------------

### Create Procfile for NIO HTTP Server

Source: https://www.swift.org/documentation/server/guides/deploying/heroku.html

Defines how Heroku should run your application. This example is for the NIO HTTP Server, binding to all interfaces and using the Heroku-assigned port.

```bash
echo "web: NIOHTTP1Server 0.0.0.0 $PORT" > Procfile
```

--------------------------------

### Create Project Directory and Template File

Source: https://www.swift.org/documentation/server/guides/deploying/aws-sam-lambda.html

Initializes the project directory and creates the `template.yml` file for AWS SAM configuration.

```bash
mkdir swift-lambda-api && cd swift-lambda-api
touch template.yml

```

--------------------------------

### Create and Navigate to Project Directory

Source: https://www.swift.org/documentation/server/guides/deploying/aws-copilot-fargate-vapor-mongo.html

Creates a new directory for your project and changes into it. This is the first step in setting up a new Vapor application.

```bash
mkdir todo-app && cd todo-app

```

--------------------------------

### Create and Build a New Project

Source: https://www.swift.org/documentation/articles/static-linux-getting-started.html

Creates a new executable Swift project and builds it locally.

```bash
$ mkdir hello
$ cd hello

```

```bash
$ swift package init --type executable

```

```bash
$ swift build
Building for debugging...
[8/8] Applying hello
Build complete! (15.29s)
$ .build/debug/hello
Hello, world!

```

--------------------------------

### Compile SwiftNIO Application using Docker

Source: https://www.swift.org/documentation/server/guides/deploying/aws.html

Compiles the SwiftNIO example HTTP server within a Docker container. This method isolates the build environment and ensures consistency.

```bash
docker run --rm  -v "$PWD:/workspace"  -w /workspace swift:5.4-amazonlinux2   /bin/bash -cl ' \
     swift build -v --static-swift-stdlib -c release
' 
```

--------------------------------

### Configure lsp-sourcekit for sourcekit-lsp integration

Source: https://www.swift.org/documentation/articles/zero-to-swift-emacs.html

Installs the `lsp-sourcekit` package and configures it to use the `find-sourcekit-lsp` function to locate the `sourcekit-lsp` executable. Requires `lsp-mode` to be loaded first.

```emacs-lisp
;; sourcekit-lsp support
(use-package lsp-sourcekit
    :ensure t
    :after lsp-mode
    :custom
    (lsp-sourcekit-executable (find-sourcekit-lsp) "Find sourcekit-lsp"))

```

--------------------------------

### Enable LSP and Set Keymaps

Source: https://www.swift.org/documentation/articles/zero-to-swift-nvim.html

Enables the sourcekit LSP and sets up keymaps for LSP actions like hover and go to definition upon LspAttach.

```lua
-- lua/config/lsp.lua
vim.lsp.enable("sourcekit")

vim.api.nvim_create_autocmd('LspAttach', {
  desc = "LSP Actions",
  callback = function(args)
    vim.keymap.set("n", "K", vim.lsp.buf.hover, {noremap = true, silent = true})
    vim.keymap.set("n", "gd", vim.lsp.buf.definition, {noremap = true, silent = true})
  end,
})
}

```

--------------------------------

### Create Plugin and Config Directories

Source: https://www.swift.org/documentation/articles/zero-to-swift-nvim.html

Creates the necessary 'lua/plugins' and 'lua/config' directories for organizing Neovim plugins and configurations.

```bash
 $  mkdir lua/plugins lua/config
```

--------------------------------

### Build and Run Swift Executable Locally

Source: https://www.swift.org/documentation/articles/swift-sdk-for-android-getting-started.html

Build the Swift package for the host system and run the executable to verify it works.

```bash
$ swift build
Building for debugging...
[8/8] Applying hello
Build complete! (15.29s)

$ .build/debug/hello
Hello, world!
```

--------------------------------

### Install Heroku CLI using Homebrew

Source: https://www.swift.org/documentation/server/guides/deploying/heroku.html

Installs the Heroku command-line interface tools using Homebrew on macOS.

```bash
brew tap heroku/brew && brew install heroku
```

--------------------------------

### Initialize SwiftPM Projects for Lambda Functions

Source: https://www.swift.org/documentation/server/guides/deploying/aws-sam-lambda.html

Use Swift Package Manager to initialize executable projects for your Lambda functions and create Dockerfiles.

```bash
mkdir -p src/put-item
cd src/put-item
swift package init --type executable
touch Dockerfile

cd ../..

mkdir -p src/get-items
cd src/get-items
swift package init --type executable
touch Dockerfile

```

--------------------------------

### Install Emacs on Debian-based Linux

Source: https://www.swift.org/documentation/articles/zero-to-swift-emacs.html

Use this command to install the full Emacs package on Debian-based systems like Ubuntu.

```bash
$ sudo apt-get install emacs

```

--------------------------------

### Initialize a Swift Executable Package

Source: https://www.swift.org/documentation/articles/wasm-getting-started.html

Creates a new directory and initializes a Swift package of type executable.

```bash
mkdir Hello
cd Hello
swift package init --type executable
```

--------------------------------

### Non-Structured Logging Example

Source: https://www.swift.org/documentation/server/guides/libraries/log-levels.html

An example of a traditional, non-structured log message that includes dynamic information within the message string.

```swift
log.info("Accepted connection \(connection.id) from \(connection.peer), total: \(connections.count)")

```

--------------------------------

### Create .swift-version file

Source: https://www.swift.org/documentation/server/guides/deploying/heroku.html

Creates a '.swift-version' file in the project root, specifying the Swift version to be used (e.g., 5.9).

```bash
echo "5.9" > .swift-version
```

--------------------------------

### Perf Warning Example

Source: https://www.swift.org/documentation/server/guides/allocations.html

This is an example of a warning message indicating that perf has lost data chunks during recording. It suggests checking IO/CPU overload.

```text
[ perf record: Woken up 189 times to write data ]
Warning:
Processed 4346 events and lost 144 chunks!

Check IO/CPU overload!

[ perf record: Captured and wrote 30.868 MB perf.data (3817 samples) ]

```

--------------------------------

### Value Preserving Type Conversion Example

Source: https://www.swift.org/documentation/api-design-guidelines

This example shows a value-preserving type conversion where the first argument does not need a label to maintain fluency.

```swift
let rgbForeground = RGBColor(cmykForeground)
```

--------------------------------

### Install lsp-ui for enhanced LSP interface

Source: https://www.swift.org/documentation/articles/zero-to-swift-emacs.html

Installs the `lsp-ui` package, which provides user interface enhancements for `lsp-mode`, such as improved diagnostics and code navigation.

```emacs-lisp
;; lsp-mode's UI modules
(use-package lsp-ui
    :ensure t)

```

--------------------------------

### Create New User

Source: https://www.swift.org/documentation/server/guides/deploying/digital-ocean.html

Create a new non-root user named 'swift' to run your application. This user will not have sudo access for enhanced security.

```bash
adduser swift

```

--------------------------------

### Configure Swift Launch Configuration

Source: https://www.swift.org/documentation/articles/getting-started-with-vscode-swift.html

Sets up a launch configuration in `launch.json` to debug a Swift executable with custom arguments and a pre-launch build task. Ensure the `program` path and `preLaunchTask` match your project structure.

```json
{
  "configurations": [
    {
      "type": "swift",
      "name": "Debug swift-executable",
      "request": "launch",
      "args": ["--hello", "world"],
      "cwd": "${workspaceFolder}",
      "program": "${workspaceFolder}/.build/debug/swift-executable",
      "preLaunchTask": "swift: Build Debug swift-executable"
    }
  ]
}

```

--------------------------------

### Build the SAM project

Source: https://www.swift.org/documentation/server/guides/deploying/aws-sam-lambda.html

Builds your SAM project, compiling Swift code into Docker images. Run from the project root.

```bash
sam build

```

--------------------------------

### Install and configure rainbow-delimiters package

Source: https://www.swift.org/documentation/articles/zero-to-swift-emacs.html

Installs the `rainbow-delimiters` package and enables it for programming modes. This feature highlights nested delimiters with different colors, improving readability.

```emacs-lisp
;; Rainbow delimiters makes nested delimiters easier to understand
(use-package rainbow-delimiters
    :ensure t
    :hook ((prog-mode . rainbow-delimiters-mode)))

```

--------------------------------

### Create Addon Directory

Source: https://www.swift.org/documentation/server/guides/deploying/aws-copilot-fargate-vapor-mongo.html

Creates the necessary directory structure for Copilot addons.

```bash
mkdir -p copilot/api/addons

```

--------------------------------

### Install Emacs on RedHat-based Linux

Source: https://www.swift.org/documentation/articles/zero-to-swift-emacs.html

Use this command to install Emacs on RedHat-based systems like Fedora. Use 'yum' on older versions if 'dnf' is not available.

```bash
$ sudo dnf install emacs

```

--------------------------------

### Install Emacs without X11 on Debian-based Linux

Source: https://www.swift.org/documentation/articles/zero-to-swift-emacs.html

Use this command to install Emacs without graphical support on Debian-based systems, suitable for servers or containers.

```bash
$ sudo apt-get install emacs-nox

```

--------------------------------

### Initializer Documentation

Source: https://www.swift.org/documentation/api-design-guidelines

Document what an initializer creates.

```swift
/// **Creates** an instance containing `n` repetitions of `x`.
init(count n: Int, repeatedElement x: Element)
```

--------------------------------

### Valgrind Memory Leak Report Example

Source: https://www.swift.org/documentation/server/guides/memory-leaks-and-usage.html

An example of a Valgrind Memcheck report showing heap summary and memory leak details, including stack traces.

```text
==1== Memcheck, a memory error detector
==1== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==1== Using Valgrind-3.13.0 and LibVEX; rerun with -h for copyright info
==1== Command: ./test
==1==
==1==
==1== HEAP SUMMARY:
==1==     in use at exit: 824 bytes in 4 blocks
==1==   total heap usage: 5 allocs, 1 frees, 73,528 bytes allocated
==1==
==1== 32 bytes in 1 blocks are definitely lost in loss record 1 of 4
==1==    at 0x4C2FB0F: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==1==    by 0x52076B1: swift_slowAlloc (in /usr/lib/swift/linux/libswiftCore.so)
==1==    by 0x5207721: swift_allocObject (in /usr/lib/swift/linux/libswiftCore.so)
==1==    by 0x108E58: $s4test12MemoryLeakerCACycfC (in /tmp/test)
==1==    by 0x10900E: $s4test28myFunctionDoingTheAllocationyyF (in /tmp/test)
==1==    by 0x108CA3: main (in /tmp/test)
==1==
==1== LEAK SUMMARY:
==1==    definitely lost: 32 bytes in 1 blocks
==1==    indirectly lost: 0 bytes in 0 blocks
==1==      possibly lost: 0 bytes in 0 blocks
==1==    still reachable: 792 bytes in 3 blocks
==1==         suppressed: 0 bytes in 0 blocks
==1== Reachable blocks (those to which a pointer was found) are not shown.
==1== To see them, rerun with: --leak-check=full --show-leak-kinds=all
==1==
==1== For counts of detected and suppressed errors, rerun with: -v
==1== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 from 0)
```

--------------------------------

### Install and configure editorconfig package

Source: https://www.swift.org/documentation/articles/zero-to-swift-emacs.html

Ensures the `editorconfig` package is installed and enables its mode. This package helps maintain consistent coding styles across different editors.

```emacs-lisp
;; .editorconfig file support
(use-package editorconfig
    :ensure t
    :config (editorconfig-mode +1))

```

--------------------------------

### Example LeakSanitizer Output

Source: https://www.swift.org/documentation/server/guides/memory-leaks-and-usage.html

This is an example of the output you might see when LeakSanitizer detects memory leaks. It details the size and number of leaked objects and their allocation call stacks.

```text
=================================================================
==478==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 32 byte(s) in 1 object(s) allocated from:
    #0 0x55f72c21ac8d  (/tmp/test+0x95c8d)
    #1 0x7f7e44e686b1  (/usr/lib/swift/linux/libswiftCore.so+0x3cb6b1)
    #2 0x55f72c24b2ce  (/tmp/test+0xc62ce)
    #3 0x55f72c24a4c3  (/tmp/test+0xc54c3)
    #4 0x7f7e43aecb96  (/lib/x86_64-linux-gnu/libc.so.6+0x21b96)

SUMMARY: AddressSanitizer: 32 byte(s) leaked in 1 allocation(s).

```

--------------------------------

### Select Xcode Version and Build Project

Source: https://www.swift.org/documentation/source-compatibility

Commands to select a specific Xcode version and then build a project at a pinned commit using the compatibility check script.

```bash
# Select Xcode 8.0 GM
sudo xcode-select -s /Applications/Xcode.app
# Build project at pinned commit against selected Xcode
./check project-path-field

```

--------------------------------

### Demangled Swift Stack Trace Example

Source: https://www.swift.org/documentation/server/guides/memory-leaks-and-usage.html

An example of a Valgrind stack trace after demangling Swift symbols, showing clearer function names and improving leak analysis.

```text
==1== 32 bytes in 1 blocks are definitely lost in loss record 1 of 4
==1==    at 0x4C2FB0F: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==1==    by 0x52076B1: swift_slowAlloc (in /usr/lib/swift/linux/libswiftCore.so)
==1==    by 0x5207721: swift_allocObject (in /usr/lib/swift/linux/libswiftCore.so)
==1==    by 0x108E58: test.MemoryLeaker.__allocating_init() -> test.MemoryLeaker (in /tmp/test)
==1==    by 0x10900E: test.myFunctionDoingTheAllocation() -> () (in /tmp/test)
==1==    by 0x108CA3: main (in /tmp/test)
```

--------------------------------

### Create Addon Parameters File

Source: https://www.swift.org/documentation/server/guides/deploying/aws-copilot-fargate-vapor-mongo.html

Creates an empty YAML file to define parameters for the addon.

```bash
touch copilot/api/addons/addons.parameters.yml

```

--------------------------------

### C++ Umbrella Header Example

Source: https://www.swift.org/documentation/cxx-interop/project-build-setup

An example of a C++ umbrella header file that includes other C++ headers. This allows Swift to import the C++ target as a Clang module.

```c++
// Header file `cxxLibrary.h`
#pragma once

#include <classImpl.h>

```

--------------------------------

### Build Application with Docker for Intel CPUs on Apple Silicon

Source: https://www.swift.org/documentation/server/guides/building.html

When building on an Apple Silicon Mac for Intel CPUs, append platform and QEMU CPU flags to the Docker run command to ensure compatibility.

```bash
$ docker run -v "$PWD:/code" -w /code --platform linux/amd64 -e QEMU_CPU=max swift:latest swift build
```

--------------------------------

### Install Swift Toolchain on Amazon Linux 2

Source: https://www.swift.org/documentation/server/guides/deploying/aws.html

Installs the Swift toolchain and its dependencies on an Amazon Linux 2 instance. This is useful for compiling Swift code directly on the server.

```bash
SwiftToolchainUrl="https://swift.org/builds/swift-5.4.1-release/amazonlinux2/swift-5.4.1-RELEASE/swift-5.4.1-RELEASE-amazonlinux2.tar.gz"
sudo yum install ruby binutils gcc glibc-static gzip libbsd libcurl libedit libicu libsqlite libstdc++-static libuuid libxml2 tar tzdata ruby -y
cd $(mktemp -d)
wget ${SwiftToolchainUrl} -O swift.tar.gz
gunzip < swift.tar.gz | sudo tar -C / -xv --strip-components 1

```

--------------------------------

### Build Project on Linux with Swift 3.0 Toolchain

Source: https://www.swift.org/documentation/source-compatibility

Commands to download and use the Swift 3.0 release toolchain on Linux to build a project. This is useful for testing compatibility on a Linux environment.

```bash
curl -O https://download.swift.org/swift-3.0-release/ubuntu1510/swift-3.0-RELEASE/swift-3.0-RELEASE-ubuntu15.10.tar.gz
tar xzvf swift-3.0-RELEASE-ubuntu15.10.tar.gz
./check project-path-field --swiftc swift-3.0-RELEASE-ubuntu15.10/usr/bin/swiftc

```

--------------------------------

### Name According to Role: Basic Example

Source: https://www.swift.org/documentation/api-design-guidelines

Name variables and parameters according to their roles rather than their type constraints. This example shows changing 'string' to 'greeting' and 'widgetFactory' to 'supplier'.

```swift
var **string** = "Hello"
protocol ViewController {
  associatedtype **View**Type : View
}
class ProductionLine {
  func restock(from **widgetFactory**: WidgetFactory)
}

```

```swift
var **greeting** = "Hello"
protocol ViewController {
  associatedtype **ContentView** : View
}
class ProductionLine {
  func restock(from **supplier**: WidgetFactory)
}

```

--------------------------------

### Install perf User Probes on Allocation Functions

Source: https://www.swift.org/documentation/server/guides/allocations.html

Installs perf user probes on the `malloc`, `calloc`, and `posix_memalign` functions in libc. This allows `perf` to track when these allocation functions are called.

```bash
# figures out the path to libc
libc_path=$(readlink -e /lib64/libc.so.6 /lib/x86_64-linux-gnu/libc.so.6)

# delete all existing user probes on libc (instead of * you can also list them individually)
perf probe --del 'probe_libc:*'

# installs a probe on `malloc`, `calloc`, and `posix_memalign`
perf probe -x "$libc_path" --add malloc --add calloc --add posix_memalign

```

--------------------------------

### Install and configure spaceline for status bar theme

Source: https://www.swift.org/documentation/articles/zero-to-swift-emacs.html

Installs the `spaceline` package and applies the `spaceline-emacs-theme`. This is an alternative or complementary package for customizing the Emacs status bar, often used with Powerline.

```emacs-lisp
;; Spaceline
(use-package spaceline
  :ensure t
  :after powerline
  :config
  (spaceline-emacs-theme))

```

--------------------------------

### Initialize Copilot Environment

Source: https://www.swift.org/documentation/server/guides/deploying/aws-copilot-fargate-vapor-mongo.html

Create a new environment for your Copilot application, such as 'dev', 'test', or 'prod'. This aligns with deployment phases.

```bash
copilot env init --name dev --app todo --default-config

```

--------------------------------

### Build and Package Swift App with Distroless

Source: https://www.swift.org/documentation/server/guides/packaging.html

This Dockerfile demonstrates packaging a Swift application using a Distroless C++ base image. It uses a multi-stage build similar to the standard Docker approach but targets a minimal runtime environment.

```dockerfile
#------- build -------
# Building using Ubuntu Bionic since its compatible with Debian runtime
FROM swift:bionic as builder

# set up the workspace
RUN mkdir /workspace
WORKDIR /workspace

# copy the source to the docker image
COPY . /workspace

RUN swift build -c release --static-swift-stdlib

#------- package -------
# Running on distroless C++ since it includes
# all(*) the runtime dependencies Swift programs need
FROM gcr.io/distroless/cc-debian10
# copy executables
COPY --from=builder /workspace/.build/release/<executable-name> /

# set the entry point (application name)
CMD ["<executable-name>"]

```

--------------------------------

### Initialize Vapor Project

Source: https://www.swift.org/documentation/server/guides/deploying/aws-copilot-fargate-vapor-mongo.html

Initializes a new Vapor project named 'api' without interactive prompts. This command sets up the basic structure for your Vapor application.

```bash
vapor new api -n

```

--------------------------------

### Demangle Symbols with addr2line and swift demangle

Source: https://www.swift.org/documentation/server/guides/memory-leaks-and-usage.html

Use addr2line to get symbol information from an executable and pipe the output to 'swift demangle' to get human-readable function names for stack traces.

```bash
# /tmp/test+0xc62ce
addr2line -e /tmp/test -a 0xc62ce -ipf | swift demangle
```

--------------------------------

### Show Release Build Binary Path

Source: https://www.swift.org/documentation/server/guides/building.html

Display the full path to the release build binary artifact. This helps in locating deployable binaries.

```bash
swift build --show-bin-path -c release
```

--------------------------------

### Create Addon Configuration File

Source: https://www.swift.org/documentation/server/guides/deploying/aws-copilot-fargate-vapor-mongo.html

Creates an empty CloudFormation YAML file for the API Gateway addon.

```bash
touch copilot/api/addons/apigateway.yml

```

--------------------------------

### Compensate for Weak Type Information: Clear Example

Source: https://www.swift.org/documentation/api-design-guidelines

Precede weakly typed parameters with a noun describing their role to restore clarity. This example refines the 'add' function signature and call site for better understanding.

```swift
func add**Observer**(_ observer: NSObject, for**KeyPath** path: String)
grid.addObserver(self, forKeyPath: graphics) // clear

```

--------------------------------

### Compensate for Weak Type Information: Vague Example

Source: https://www.swift.org/documentation/api-design-guidelines

When parameter types are generic (e.g., NSObject, Any, String), context at the use site may be vague. This example shows a less clear 'add' function signature and call.

```swift
func add(_ observer: NSObject, for keyPath: String)

grid.add(self, for: graphics) // vague

```

--------------------------------

### Initialize lazy.nvim Plugin Manager

Source: https://www.swift.org/documentation/articles/zero-to-swift-nvim.html

This Lua script initializes the lazy.nvim plugin manager. It clones the repository if it doesn't exist and sets up the plugin configuration.

```lua
-- init.lua
local lazypath = vim.fn.stdpath("data") .. "/lazy/lazy.nvim"
if not (vim.uv or vim.loop).fs_stat(lazypath) then
  local lazyrepo = "https://github.com/folke/lazy.nvim.git"
  local out = vim.fn.system({ "git", "clone", "--filter=blob:none", "--branch=stable", lazyrepo, lazypath })
  if vim.v.shell_error ~= 0 then
    vim.api.nvim_echo({
      { "Failed to clone lazy.nvim:\n", "ErrorMsg" },
      { out, "WarningMsg" },
      { "\nPress any key to exit..." },
    }, true, {})
    vim.fn.getchar()
    os.exit(1)
  end
end
vim.opt.rtp:prepend(lazypath)
require("lazy").setup("plugins", {
  ui = {
    icons = {
      cmd = "",
      config = "",
      event = "",
      ft = "",
      init = "",
      keys = "",
      plugin = "",
      runtime = "",
      require = "",
      source = "",
      start = "",
      task = "",
      lazy = "",
    },
  },
})
require("config.lsp")

vim.opt.wildmenu = true
vim.opt.wildmode = "list:longest,list:full" -- don't insert, show options

-- line numbers
vim.opt.nu = true
vim.opt.rnu = true

-- textwrap at 80 cols
vim.opt.tw = 80

-- set solarized colorscheme.
-- NOTE: Uncomment this if you have installed solarized, otherwise you'll see
--       errors.
-- vim.cmd.background = "dark"
-- vim.cmd.colorscheme("solarized")
-- vim.api.nvim_set_hl(0, "NormalFloat", { bg = "none" })

```

--------------------------------

### Build Statically Linked Linux Binary (ARM64)

Source: https://www.swift.org/documentation/articles/static-linux-getting-started.html

Builds a statically linked executable for the ARM64 Linux architecture using the specified Swift SDK.

```bash
$ swift build --swift-sdk aarch64-swift-linux-musl
Building for debugging...
[8/8] Linking hello
Build complete! (2.00s)
$ file .build/aarch64-swift-linux-musl/debug/hello
.build/aarch64-swift-linux-musl/debug/hello: ELF 64-bit LSB executable, ARM aarch64, version 1 (SYSV), statically linked, with debug_info, not stripped

```

--------------------------------

### Remove Installed SDK

Source: https://www.swift.org/documentation/articles/static-linux-getting-started.html

Removes a specified Static Linux SDK from the system.

```bash
$ swift sdk remove <name-of-SDK>

```

--------------------------------

### Function Signature with Awkward Parameter Names

Source: https://www.swift.org/documentation/api-design-guidelines

Shows examples of parameter names that lead to awkward or ungrammatical documentation.

```swift
/// Return an `Array` containing the elements of `self`
/// that satisfy `**includedInResult**`.
func filter(_ **includedInResult**: (Element) -> Bool) -> [Generator.Element]

/// Replace the **range of elements indicated by `r`** with
/// the contents of `**with**`.
mutating func replaceRange(_ **r**: Range, **with**: [E])

```
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