In order to integrate a new language lang into Guile’s compiler
system, one has to create the module (language lang spec)
containing the language definition and referencing the parser,
compiler and other routines processing it. The module hierarchy in
(language brainfuck) defines a very basic Brainfuck
implementation meant to serve as easy-to-understand example on how to
do this. See for instance http://en.wikipedia.org/wiki/Brainfuck
for more information about the Brainfuck language itself.