thank you for your post.
I have looked around for a bit, but cannot find anything promising. The best options I see would be:
(1) Write fuzzylite in swift. The library is well structured, which means that it would not be too hard to rewrite it in Swift. I could help you out by explaining whatever you have trouble with, and guiding you where to start and what to work on. Perhaps you could check the source code of fuzzylite or jfuzzylite and decide for yourself. If you were to start, the most reasonable way would be in the following order: Norms (T-Norms and S-Norms), Hedges, Terms, Variables, Rules, Engine. As for Importers and Exporters, I would only include FllImporters and FllExporters.
(2) Use fuzzylite binary. In fuzzylite (C++) and jfuzzylite (java), there is a console application that allows you to load an engine from FLL code, pass input values, and automatically obtain output values. You would need to execute the binary from your code. Check the binary.
juan@macbook:~/Development/fl/fuzzylite/fuzzylite/bin$ ./fuzzylite usage: fuzzylite inputfile outputfile or: fuzzylite [-i inputfile] [-if format] [-o outputfile] [-of format] [-example letter] [-decimals number] [-d datafile] [-dmaximum number] [-dheader boolean] [-dinputs boolean] where: -i inputfile file to import your engine from -if format format of the file to import (fll | fis | fcl) -o outputfile file to export your engine to -of format format of the file to export (fll | fld | cpp | java | fis | fcl) -example letter if not inputfile, built-in example to use as engine: (m)amdani or (t)akagi-sugeno -decimals number number of decimals to write floating-poing values -d datafile if exporting to fld, file of input values to evaluate your engine on -dmaximum number if exporting to fld without datafile, maximum number of results to export -dheader boolean if true and exporting to fld, include headers -dinputs boolean if true and exporting to fld, include input values Visit http://fuzzylite.com/ for more information. Copyright (C) 2010-2015 by FuzzyLite Limited. All rights reserved.