6.20 Foreign Function Interface
The more one hacks in Scheme, the more one realizes that there are
actually two computational worlds: one which is warm and alive, that
land of parentheses, and one cold and dead, the land of C and its ilk.
But yet we as programmers live in both worlds, and Guile itself is half
implemented in C. So it is that Guile’s living half pays respect to its
dead counterpart, via a spectrum of interfaces to C ranging from dynamic
loading of Scheme primitives to dynamic binding of stock C library
procedures.