how I made my languages professor twitch

Today in programming languages, the professor started going over Lisp. I was surprised to learn that function names are case insensitive in Lisp, so if you declare a function called incrementAll, you can invoke it by calling INCREMENTALL, incrementall, or any other case variant. I forgot about this because I’m not used to case insensitive function names in a language, so later when my professor typed incrementall on his laptop, I pointed out that the ‘a’ should be capitalized.

Him: “Oh, that won’t matter, it’s case insensitive.”
Me: “Oh! …So it’s like Visual Basic.”

That made him cringe a bit, being a language purist and a bit of an open source/Linux zealot to boot. Visual Basic was the only other language I could think of though where there’s any kind of case insensitivity, e.g. if expr then is the same as If expr Then in VB.