The new version 3 of the REBOL programming language supports
extensions written in other languages. Extensions are implemented on top of the
modules framework, which is also new. Extensions can be separate dynamically loaded libraries, or they can be embedded in the REBOL executable. In fact, REBOL 3 is now highly modularised: a number of its subsystems are embedded modules, and subsystems written in C and C++ are embedded extensions. Those modules and extensions are part of the
open host kit, so that custom collections can be compiled into REBOL executables.