There are several implementations that have their differences. It's kinda similar to "Lisps" in plural. Lisp is a programming language, but it's also a family o

There are several implementations that have their differences. It's kinda similar to "Lisps" in plural. Lisp is a programming language, but it's also a family of similar languages. Also, languages like K and J, maybe Q could be considered part of APL family due to their array oriented design and single character operator syntax.