I used to write trading systems for Amibroker. This one signaled the 2009 march bull market in equities and oil. But it is a swing/longterm trading system. I was a daytrader so it is not really useful for that.
The trading domain knowledge can be found from various online resources. I used to make a 200+ slide powerpoint on the technical analysis aspect of trading but it is probably irrelevant now as markets had changed much since the introduction of algorithmic and high-frequency trading.
I was writing that script for Amibroker platform (https://www.amibroker.com) but I believe the market leader is probably something like MetaTrader (https://www.metatrader4.com). Also, for developers or software engineers familiar with Python, Quantopian might be something you'll enjoy using (https://www.quantopian.com).
Have fun! This one is a trend-following system for swing/position trading. It hasn't been backtested to factor new market behavior for the last 6-7 years, so it'll probably do badly now. My failure was not being able to convert that for daytrading timeframe.
PS: anyway, sorry for digressing away from the topic of the HN thread lol
https://github.com/tebelorg/Tump/blob/master/trading_z.js