Julia's multiple dispatch explained with Pokemons
This post shows MD but it misses the forest for the trees. To riff on the blog post linked below, “what if you have an Onyx holding a hard stone executing Earthquake in a Sandstorm against a Flygon with the ability Hover?”<p>The answer is that rules should be encoded in data structures and not in the type system. The type system is for structuring how your program runs not its logical correctness. If you have a coworker who, upon hearing that you have a new business requirement, says “oh goodie I’ll reconfigure our whole type system!” please report them to the relevant local authorities.<p>If you aren’t writing code that handles types as 1st class objects like a parser, please reconsider using this pattern. If you are writing a parser, this isn’t even the fancy way to do it anymore, but at least you’re holding the book upside right.<p>The funny thing is that the Pokémon valences are already in a table at the start of the blog post; an ideal location to store such data!<p><a href="https://ericlippert.com/2015/04/27/wizards-and-warriors-part-one/" rel="nofollow">https://ericlippert.com/2015/04/27/wizards-and-warriors-part...</a><p>EDIT: this is not shade on the OP, I just don’t want junior (or senior!) engineers reading this and implementing their business logic in MD because I don’t want to debug it or extend it!