Evolution Is Still a Valid Machine Learning Technique

Summary

Harper Evolves I want you to read that title as literally as possible. Harper is now capable of evolution. This past week, I've been working on a system that should allow us to handle more complex grammatical cases and contexts, faster. I believe it will improve our ability to add new grammatical rules to Harper by somewhere between 500% and 1,000%. To top it off, this system does it without slowing Harper itself down or increasing the memory footprint. Let's get into it. The Problem There are several unique methodologies at play when Harper goes about grammar checking. Which strategy depends on the grammatical rule in question. Today, we're interested in expression rules. For the curious, I have recently written a reflection on expression rules, as well as a guide for anyone interested in producing them. This post, however, will not recount information I've already written on this blog. By count, expression rules make up the majority of grammatical rules Harper is currently capable of detecting. This is because they are fast, easy to write, and most importantly, easy to review. There are, however, occasional hiccups that I encounter when tackling a problem. The English language is tricky and often it contradicts itself. I will often try to write a rule which covers a certain case, only to find that it doesn't cover all cases. I can iterate, but it often becomes tedious and time-consuming. The Solution Last week, I threw in the towel. I was tired of iterating ceaselessly towards a goal, only to have a new one to tackle after that. So I decided I would let the computer iterate for me. Harper's expressions are essentially small programs which are able to identify the locations of given patterns in natural language. They are constructed at runtime, but they run exceedingly fast because they tend to be amenable to modern branch prediction. We can use this fact to our advantage. When generating an expression that detects a particular grammatical rule, the new system (whi...