The ISO4217 standard defines currencies used throughout the world. Among other properties, the standard assigns codes (e.g. USD) and numbers (e.g. 840) to those currencies. This repo is simply a script that generates a Swift dictionary of the format [Int32: String] which contains currency numbers as its keys, and maps them to currency codes.
The script uses an XML file as its source. This repo already contains ISO4217.xml, downloaded from here. If you need to update the source, replace the XML file, and make sure the tag names in the python script still match the tags used in the XML.
make_currencies.py is a simple XML-parsing script which prints a Swift dictionary. It uses minidom to parse XML, which should be available on most systems. To run it and redirect the output to a file, run
python make_currencies.py > currencies.swift
You can then paste the contents of currencies.swift into your project as needed.