This is about the package SwiftMath by @mgriebling
I know little about Swift, so I was not able to create an app using his package. I downloaded and tried to run his SwiftMathDemo. It didn't work, the errors were "No account for team ***" and "No signing certificate..."
Then I created a new app and just copied everything from Mike's files. Initially it worked but after two hours failed. First I gave it the url of the package and then installed the package locally. The message was "Missing package product 'SwiftMath'".
You've almost got it. You just need to add the following package path to XCode: https://github.com/mgriebling/SwiftMath.git.
In the demo project select the project SwiftMathDemo and go to the Package Dependencies tab. Click on the + and enter the https://github.com/mgriebling/SwiftMath.git. That should add the missing package to your project. Just compile and run.
Note: If you use Xcode to install the project from github using the Source Control/Clone... menu item, the package will be automatically installed for you.
Regarding the program failure, can you please give more information such as the LaTeX command you were trying and any compiler debug information available.
To clear the "No account for team" message, in Xcode, select the SwiftMathDemo target, and choose the Signing & Capabilities tab. Under Signing select the team None or whichever team you have created. Read up on Xcode Signing permissions for more info.
Thanks a lot, it worked. Before doing what you recommend I deleted what I had done. In the SwiftMathDemo repository there is an option "Open with Xcode", so I didn't even have to worry about the dependency.
Now I am going to try tweaking your Demo and cross my fingers.