In computer programming, the Basic Object System (BOS) is a C programming language-callable library (computer science) that implements the notion of object (computing) and which uses
tcl as its interpreter (computer software) for interpreted method (computer science)s (you can have compiled methods in C, and mix compiled and interpreted methods in the same object, plus lots more). You can subclass and mix in existing objects using BOS to extend, among other things, the set of tk widgets. BOS is a class-free object system, also called a prototype-based object system; it is modelled loosely on the Self (programming language) system from Stanford University.