Topic summary
Open recursion
Extracted from the Wikipedia article This (computer programming).
Open recursion
The dispatch semantics of this, namely that method calls on this are dynamically dispatched, is known as open recursion, and means that these methods can be overridden by derived classes or objects. By contrast, direct named recursion or anonymous recursion of a function uses closed recursion, with static dispatch. For example, in the following Perl code for the factorial, the token __SUB__ is a reference to the current function: