Importing classes from playground page into another page

Question

Note: This is a different question than importing generic swift files (which can be done using the Sources folder).

I have a playground with 2 pages and I would like to use a protocol defined in the first page in the second page. I'll use an example of JSON conversion.

JSON.xcplaygroundpage

import Foundation

protocol JSONConvertible {
    func jsonValue() -> String
}

JSONArray.xcplaygroundpage

import Foundation

//Undeclared type JSONConvertible
extension Array : JSONConvertible {

}

I have tried the following imports:

import MyPlayground
import MyPlayground.JSON
import JSON
import JSON.Contents (in finder the file name is actually Contents.swift)

I have also tried adding JSON.xcplaygroundpage into the Source folder of JSONArray as well as the Resources folder.

Note: I realize that I could put the protocol definition in a separate JSON.swift and include that in my project Sources folder. That doesn't really answer my question.

Even in Xcode 8, you cannot import one playground page into another. However, you can now put code common across multiple pages into a source file. I hope this solves your problem. — Jeff, Jun 14 '17 at 18:33

score 8 · Answer 1 · edited Oct 16 '17 at 12:01

This is working in Xcode 8.3.3.

For code common to multiple pages, put it in separate files under top-level Sources group. Be sure to have proper Swift access control keywords in the right places.

Note from http://help.apple.com/xcode/mac/8.2/#/devfa5bea3af:

...the auxiliary Swift source file must export it using the public keyword. This includes classes, methods, functions, variables, and protocols.

Common.swift:

public class DoIExist { public init(){ print("Woot!")} }

Then you can reference it in all of the other pages. Like this:

Page2:

//: [Previous](@previous)

let d = DoIExist()

//: [Next](@next)

You can see that it works because of the console output ("Woot!") and the view results gutter.

To achieve this, I followed the directions at the Apple Xcode documentation about Playgrounds. When Apple inevitably moves those docs and does not provide a forwarding link, read on for how I found it.

I searched for the clues found in the link in cocoapriest's answer: "ios recipes Playground Help Add Auxilliary Code to a Playground". This leads to a document Apple is currently calling "Xcode Help" in a chapter titled "Use playgrounds" in a section titled "Add auxiliary code to a playground".

My original intention was to create pages where you walked through creating a protocol and then used it later. However, this mostly answers the question because I could add my own version to subsequent page's Sources folder. — Kevin, Jun 15 '17 at 01:48

score -1 · Answer 2 · answered Jun 09 '16 at 11:06

-1

Just got this to work with this instruction by Apple: https://developer.apple.com/library/ios/recipes/Playground_Help/Chapters/AddAuxilliaryCodetoaPlayground.html

Make sure to declare your classes are public. Also, I had to re-start the Xcode to take the effect.

answered Jun 09 '16 at 11:06

cocoapriest

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To clarify, you were able to declare a file in one page and import into another page without duplicating the file? I wasn't able to accomplish that with the link you provided – Kevin Jun 09 '16 at 15:22
are you sure you exactly followed all steps? And: there was no "import" in that sense: it was imported automatically for me. – cocoapriest Jun 09 '16 at 18:46
The link is broken. Please fix it and ideally put a description of the steps in the answer so that if Apple moves it again, it doesn't matter so much. The answer as currently written is completely useless. – JeremyP Jan 03 '17 at 11:01
Honestly, if you had not posted that link I would have never tracked down where Apple moved the docs. Thank you. – Jeff Jun 14 '17 at 18:26

Importing classes from playground page into another page

2 Answers2