What is open recursion?

Question

What is open recursion? Is it specific to OOP?

(I came across this term in this tweet by Daniel Spiewak.)

Answer 1

just copying http://www.comlab.ox.ac.uk/people/ralf.hinze/talks/Open.pdf: "Open recursion Another handy feature offered by most languages with objects and classes is the ability for one method body to invoke another method of the same object via a special variable called self or, in some langauges, this. The special behavior of self is that it is late-bound, allowing a method defined in one class to invoke another method that is defined later, in some subclass of the first. "