1. 1.1.3

    ArgumentParser

    Straightforward, type-safe argument parsing for Swift.

    import ArgumentParser

    Overview

    By using ArgumentParser, you can create a command-line interface tool by declaring simple Swift types. Begin by declaring a type that defines the information that you need to collect from the command line. Decorate each stored property with one of ArgumentParser‘s property wrappers, declare conformance to ParsableCommand, and implement your command’s logic in its run() method.

    import ArgumentParser
    
    @main
    struct Repeat: ParsableCommand {
        @Argument(help: "The phrase to repeat.")
        var phrase: String
    
        @Option(help: "The number of times to repeat 'phrase'.")
        var count: Int?
    
        mutating func run() throws {
            let repeatCount = count ?? 2
            for _ in 0..<repeatCount {
                print(phrase)
            }
        }
    }

    When a user executes your command, the ArgumentParser library parses the command-line arguments, instantiates your command type, and then either calls your run() method or exits with a useful message.

    The output of the Repeat command, declared above.

    Additional Resources

    Topics

    Essentials

    Arguments, Options, and Flags

    Property Customization

    Custom Types

    Validation and Errors

    Shell Completion Scripts

    Advanced Topics

    Members

    Structures

    Protocols

    Removed Members

    Protocols