I omitted this to keep it simple (this is why I wrote non-English rather than non-ASCII, I actually am a proponent of active usage of proper Unicode symbols lik

I omitted this to keep it simple (this is why I wrote non-English rather than non-ASCII, I actually am a proponent of active usage of proper Unicode symbols like ⇒, ≠, etc, and also TUIs) but yes, I would prefer a rather extended English char-set including Greek letters, mathematical symbols, pseudographics etc. These can be useful and are not much trickier than English letters. But I would certainly like to see at least a warning (I would even prefer an Error actually) if my code file includes anything related to RTL, complex character composition or non-Latin letters other than Greek.