Hmm. #Prolog and #Mercury require variable names start with uppercase. Otherwise they would be mistaken for predicates (or functions).
Camel case and snake case - Rosetta Code https://rosettacode.org/wiki/Camel_case_and_snake_case
I am very much in favor of what I just learnt is ‘snake case’, but nevertheless often use whatever the convention is. (Unfortunately, Standard ML is a camel case language, or I’d like it more. And some other languages won’t let you use underscores, for heck’s sake.)
Follow
@chemoelectric prolog variable names can be all lower case if prefixed with an underscore.
@tetrislife My favorite is actually Scheme, where you can stick almost anything in a name, and the convention is the-lisp-way-of-naming-things.
@tetrislife Can a predicate’s name start with an underscore, then?