Swift Play Experimental

Feature overview

The Swift Play Experimental project contains a Playgrounds library that provides a #Playground macro for declaring runnable blocks of code in any Swift file. Being in the same file allows the playground code to access private entities in the file.

$ cat Sources/Fibonacci/Fibonacci.swift
func fibonacci(_ n: Int) -> Int {
 ...
}

import Playgrounds

#Playground("Fibonacci") {
  for n in 0..<10 {
    print("fibonacci(\(n)) = \(fibonacci(n))")
  }
}

Tools API

Swift tools and IDEs can use the provided tools-based API to enumerate and run playgrounds found in a process.

let foundPlaygrounds = __Playground.__allPlaygrounds()
print("Found playgrounds:")
for playground in foundPlaygrounds {
    print("* \(playground.__displayName)")
}
    
if let playground = __Playground.__getPlayground(named: "Fibonacci") {
    try await playground.__run()
}

For example, a prototype Swift Package Manager branch adds a swift play command which can be used to list and execute playgrounds found in a package.

For example:

$ swift play --list  
Building for debugging...
Found 1 Playground
* Fibonacci/Fibonacci.swift:23 "Fibonacci"

$ swift play Fibonacci
Building for debugging...
---- Running Playground "Fibonacci" - Hit ^C to quit ----
Fibonacci(7) = 21
^C

See CONTRIBUTING.md for details on trying out Swift Play Experimental with the Swift Package Manager "swift play" prototype.

Cross-platform support

macOS is supported. Other platforms to be supported soon.