I'm sure the code works very well for its intended purpose, but I'm kind of wary of the idea that using obscure abbreviations like 'posf', 'arem', 'vis', 'ind' etc. makes you "expert hacker".

I don't agree that code should always be designed to be perfectly readable by outsiders. If such abbreviations works for the people who have to maintain the code, more power to them. But I disagree than this is somehow proof of superior skill.