 new commands.
Furthermore, a special foreign function interface defines how these
new commands are supposed to hook into the interpreter.
</p>

<p>
Typically, when you add a new command to a scripting interpreter
you need to do two things; first you need to write a special
"wrapper" function that serves as the glue between the interpreter
and the underlying C function.  Then you need to give the interpreter
information about the wrapper by providing details about the name of the
function, arguments, and so