This is a Smalltalk/Squeak program I worked on in University back in 2008. Apparently, it is still maintained and on GitHub now. As you can see, it's all text files, e.g. here is a simple asString method: https://github.com/HPI-SWA-Teaching/SwaLint/blob/master/pack...

I wouldn't call it exactly portable, as you need a Squeak image to run it. Then again, I wouldn't call a C-program written against the Win32 API portable, just because it is saved in text-files ;-)