@Akiva I think the fact that you have to maintain even one parser (in my case several and in different languages) is horrid. Standard formats exist for a reason - they can represent the data you need them to - and with extremely little effort on your part, because those parsers have been built, refined and are maintained. The custom text format is also extremely specialized knowledge, meaning that usually only one or two developers will be familiar enough with the format to successfully maintain it. That should speak volumes. Most people are familiar with CML, JSON - few know custom formats.

@Akiva I have to work with a custom text format developed by my workplace that literally reinvents the wheel. I have to maintain 4 parsers in 3 languages (Javascript, Java and Objective-C) for it, and it's a fricking nightmare. Do the right thing now and abolish this custom text format nonsense. I cannot stress enough how huge of a maintenance nightmare this will become a few years down the road. Use existing structured formats, XML, JSON, etc.

Christophe, thank you so much for such an amazing answer! I'm sorry that I wasn't clear enough in my original question about the purpose of the polymorphism, causing you to rewrite your whole answer - of course that wasn't my intention! I'm going to talk to some of my linguistics professors for additional ideas, but I think that this is the approach that I'll take. I'm trying to build a structure that is sane and also extensible for other languages that may not have structural similarities to the implemented languages - I think this is the answer to that problem!

Thanks for your answer! I updated my question - my use case is extremely simple - to codify simple rules relating to word forms for different classes, e.g. nouns and verbs.

@gardenhead I updated my question. I understand that this isn't how data is structured in NLP tools :)

@axl The secondary feature branches (e.g. implementing new damage calculations for the engine) get merged back into the long-living feature branch for the engine.

@gnasher729 "10-hour XXXX" videos on Youtube is a good identifier that indeed, some people just want to loop something forever.

Thanks for your input Doc! I ended up going the route of the command pattern and it worked out very well! My implementation is extremely basic, at least so far, so there was no simpler solution available.

@DocBrown naming, I suppose. It seems that my initial Action type is pretty much a Command, as you mentioned - so really, my initial design was a sort-of command pattern. At first glance, the command pattern seemed really different to what I had, but I suppose that the naming threw me off. Would you recommend such a pattern for this kind of task? It seems to fit well, at least in my opinion, but I'm no expert!