Money VS spylls

Many other options are available to customize this for your Ruby on Rails app. Check out the full details in the money and money-rails guides.

For now I just try to use better objects, avoiding primitive datatypes in internal code (using the null object pattern or an option/maybe class can go a long way), and using gems that do the same, such as dry-rb and money.

Java has to have a modern money library by now? Ruby has one => https://github.com/RubyMoney/money

Make sure to refer to the docs for more of the provided currency attributes, such as iso_code (which returns the international three-digit code of that currency) and decimal_mark (the char between the value and the fraction of the money data), among others.

In my experience of working on complicated algorithmic project (spylls spellchecker) in Python after 15+ years of Ruby, I really liked the gradual typing experience: you write dynamic code to get a grip of the logic, and then start to add typing here and there - and it does help to clarify design, catch accidental null possibility, and in general make inter-module API more visible.

Currently, Spylls has ≈1.5k lines of library code in 14 files. It conforms (with some reservations) to all Hunspell's integrational tests. Those tests look like a set of files each, consisting of "test dictionary + what words should be considered good, what words should be considered bad, what should be suggested instead of the bad words", and there are 127 of such sets to pass. There are 2 thousand comment lines in the code, explaining thoroughly every detail of the algorithm and rendered at the Spylls documentation site; note that besides docstrings at the beginning of each class and method, there are also inline comments in code—that's why the documentation site uses custom theme with inline "Show code" feature.