The only legal characters in a BANCStar program are the digits 0 through 9, comma, minus sign, and carriage return. Blank lines are not allowed. If a "." appears anywhere in the file, the compiler will crash.
https://geocities.restorativland.org/ResearchTriangle/Station/2266/tarpit/bancstar.html
@neauoire > "You get used to it, though. Your brain does the translating. I don't even see the code, ..."