I am learning RUST. I pick up languages in a day these days. Not the idioms, but the language. Once you seen several, these are regurgitation of the others, trying to fix their problems. RUST appears to be a better Go. https://www.rust-lang.org/en-US/
HACK tries to bring together ideas from functional programming (and other paradigms) to Php. https://code.facebook.com/posts/264544830379293/hack-a-new-programming-language-for-hhvm/
I'm not sure how you'd use PHP or HACK to program trading software, it seems like it would be trying to use a server side web development language for something it's not optimized for? I say this as someone who would love to be able to throw stuff together in PHP to test concepts. I don't find it amenable to trading but would love to figure out how it could be.
EasyLanguage (TradeStation) is the best programming language for traders. PowerLanguage (MultiCharts) almost fully compatible with EasyLanguage. C is the basis for many programming languages (MetaTrader MQL, AmiBroker AFL etc) C# use many trading platforms (NinjaTrader, Wealth-Lab etc)