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Beak
Peck into your Swift files from the command line
Beak can take a standard Swift file and then list and run any public global functions in it via a command line interface.
This is useful for scripting and for make-like files written in Swift. You can replace make
or rake
files with code written in Swift!
An example Swift script:
// This links https://github.com/kylef/PathKit as a dependency
// beak: kylef/PathKit @ 1.0.0
import PathKit // from the dependency listed above
import Foundation
/// Releases the product
/// - Parameters:
/// - version: the version to release
public func release(version: String) throws {
// implementation here
print("version \(version) released!")
}
/// Installs the product
public func install() throws {
// implementation here
print("installed")
}
$ beak list
release: Releases the product
install: Installs the product
$ beak run release --version 1.2.0
version 1.2.0 released!
How does it work?
Beak analyzes your Swift file via SourceKit and finds all public and global functions. It uses information about the function and parameter names, types and default values to build up a command line interface. It also uses standard comment docs to build up descriptive help.
Beak can parse special comments at the top of your script so it can pull in dependencies via the Swift Package Manager.
By default Beak looks for a file called beak.swift
in your current directory, otherwise you can pass a path to a different swift file with --path
. This repo itself has a Beak file for running build scripts.
Installing
Make sure Xcode 10.2+ is installed first.
Mint
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$ mint install yonaskolb/beak
Homebrew
$ brew tap yonaskolb/Beak https://github.com/yonaskolb/Beak.git
$ brew install Beak
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Swift PM and Beak This uses Swift PM to build and run beak from this repo, which then runs the install
function inside the Beak.swift
file also incuded in this repo. So meta!
$ git clone https://github.com/yonaskolb/Beak.git
$ cd Beak
$ swift run beak run install
Usage
List functions:
This shows all the functions that can be run
$ beak list
release: Releases the product
install: Installs the product
Run a function:
This runs a specific function with parameters. Note that any top level expressions in the swift file will also be run before this function.
$ beak run release --version 1.2.0
version 1.2.0 released
Run the swift file
It's also possible to just run the whole script instead of a specific function
$ beak run
Edit the swift file
This generates and opens an Xcode project with all dependencies linked, which is useful for code completion if you have defined any dependencies. The command line will prompt you to type c
to commit any changes you made in Xcode back to the original file
$ beak edit
generating project
You can always use --help
to get more information about a command or a function. This will use information from the doc comments.
Functions
For function to be accessible they must be global and declared public. Any non-public functions can be as helper functions, but won't be seen by Beak.
Functions can be throwing, with any errors thrown printed using CustomStringConvertible
. This makes it easy to fail your tasks. For now you must include an import Foundation
in your script to have throwing functions
Parameters
Any parameters without default values will be required.
Param types of Int
, Bool
, and String
are natively supported. All other types will be passed exactly as they are as raw values, so if it compiles you can pass in anything, for example an enum value--buildType .debug
.
Function parameters without labels will can be used with positional arguments:
public func release(_ version: String) { }
beak run release 1.2.0
Dependencies
Sometimes it's useful to be able to pull in other Swift packages as dependencies to use in your script. This can be done by adding some special comments at the top of your file. It must take the form:
// beak: {repo} {library} {library} ... @ {version}`
where items in {}
are:
- repo: is the git repo where a Swift package resides. This can take a short form of
user/repo
or an extended formhttps://github.com/user/repo.git
- library: a space delimited list of libraries to include from this package. This defaults to the repo name, which is usually what you want.
- version: the version of this package to include. This can either be a simple version string, or any of the types allowed by the Swift Package Manager
Requirement
static members egbranch:develop
or.branch("develop")
revision:ab794ebb
or.revision("ab794ebb")
exact:1.2.0
or.exact("1.2.0")
.upToNextMajor(from: "1.2.0")
.upToNextMinor(from: "1.2.3")
Some examples:
// beak: JohnSundell/ShellOut @ 2.0.0
// beak: kylef/PathKit @ upToNextMajor:0.9.0
// beak: apple/swift-package-manager Utility @ branch:master
import Foundation
import Pathkit
import ShellOut
import Utility
You can use beak edit
to get code completion for these imported dependencies.
Shebang
If you put a beak shebang at the top of your swift file and then run chmod a+x beak.swift
on it to make it executable, you will be able to execute it directly without calling beak.
tasks.swift
#!/usr/bin/env beak --path
public func foo() {
print("hello foo")
}
public func bar() {
print("hello bar")
}
$ chmod a+x tasks.swift
$ ./tasks.swift run foo
hello foo
If you then place this file into usr/local/bin
you could run this file from anywhere:
$ cp tasks.swift /usr/local/bin/tasks
$ tasks run bar
hello bar
To automatically insert the run
option, you can change your shebang to #!/usr/bin/env beak run --path
.
Alternatives
License
Beak is licensed under the MIT license. See LICENSE for more info.