This third and final part of the series is the most interesting one yet — my take. It involves transferring the source code, almost as is, from the script to the library.

This is the beauty of writing scripts in Swift using swift-sh, or java 11’s JEP 330 feature — the code re-use between the script and the supporting application or library.

So then — here’s the pull request that shows the code transfer and here are some notes for each of the commits involved in it :

First commit, b97d350, does the most interesting part as it removes the function getPrice’s source code located in Scripts/binancePrice.swift and adds it to Sources/abc/abc.swift . Now all that’s left is for the script to import abc // ../../abc and so making swift-sh import the local library’s code, then call getPrice function accordingly .

This also involves removing from the script the Alamofire and SwiftyJSON imports and adding them as dependencies to the abc library, inside Package.swift file. Recompiling the entire ensemble gave an error, however, as Alamofire complained it only supports macOS versions higher than 10.12 and so an adjustment had to be made in Package.swift in order to accommodate this.

One more recompilation proved all’s in place this time :

3-writing-scripts-in-swift-language-1.png

Now — just because the function has been transferred into the library as is, does not mean that the job is completely done from the overall project point of view; this is because:

  • Xcode is now more strict with types and other source code quality issues, and
  • the library source code, taken as a full-fledged piece of software, is just not close enough to a decent level of quality.

Second commit, c479631, deals with cleaning up the Xcode warnings — what’s easy as it’s actually only one.

Third commit, d118882, however, is relatively more complex :

A new file, Sources/abc/binance.swift has been created and the getPrice function has been moved inside it — this is for the reason of code structuring and isolation; getPrice was really not that close in functionality with abc.swift’s Hello World …

Another new file, Tests/abcTests/binanceTests.swift has been created and two test units testGetPriceValid and testGetPriceInvalid have been written in order to make sure function getPrice works as per the original implementation.

These changes required re-issuing swift package generate-xcodeproj in the command line in order for Xcode take into consideration the newly introduced two files.

This is pretty much it . Enjoy !