This is a masterclass in tutorial-writing. The author explains the Earley algorithm in great detail, distilling a ton of info in academic papers in a very readable form. He admits early (harhar) on that he did it mostly to encourage adoption of the algorithm.
This style of technical writing is severely underrepresented in tech currently, as many people seem to write to promote themselves. Ironically, the author’s approach promotes then far more (at least in my book) because it shows the extreme clarity of thought and detail.