This was originally a simple gem I wrote a while back called romanic that handles roman numerals and eventually posted online. I've posted this variation of it on github now because I used it as an example of basic Ruby testing in 67-272 in the spring of 2014. There are two branches: master (which passes all the tests) and flawed (which ad-hoc testing seems to say is fine, but the full test suite finds a flaw).
The romanic module has two sub-modules: RomanicIntegers and RomanicStrings. The RomanicIntegers is designed a to_roman method to Ruby's Fixnum class. This would allow you to write 14.to_roman and get back 'XIV' as a string. The RomanicStrings is designed a from_roman method to Ruby's String class. This would allow you to write XIV.to_roman and get back the number 14. If the value is out-of-bounds (less than 1, 5000 or greater) or just isn't a romanic string ('bad') then nil is returned.
If you want to really use the functionality (not that Roman numeral conversions are a high demand operation, but who knows what nefarious purposes you could use it for), installing this gem is pretty simple -- just type on the command line:
$ gem install romanic
And add this gem into any other code with:
require 'romanic'
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Prof. H
February 2014