There is an official way to install Swift online. Find it. Use it. I recommend puting that last export statement in your .bashrc file because what export does is make something available everywhere for your session. With .bashrc you can use Swift in terminal any time. Also, there is an official way to make Swift libraries if you can find it. You can also just run Swift with in terminal "swift file.swift" where swift is like that and you are in folder with file.swift. Replace name of file.swift with your actual file name.
I find just making Swift that can run and either produce errors or not enough. Note that this method will only report syntax errors and will not report wrong references to functions or not found libraries. If you really want to make an app or library well for an Apple product, you really need an Apple product. That is not to say you can't write code for Apple devices on Linux though.