If you deal with people in your software at some point these three,
countries, currencies, and languages will become relevant.
Instead of hacking it why not use structured recognized information.
This is where
https://code.dlang.org/packages/countries_currencies_languages
comes in. As the name stats this package contains a lot of information
about these three topics.
On top of all information of iso639, iso3166, and iso4217 some additional information is contained.