Vicare Scheme: compiler dircalls let

There are other integration possibilities when the operator of an application form is a complex expression:

((let ((?lhs ?rhs) ...) ?body) ?rand ...)
===> (let ((?lhs ?rhs) ...)
       (?body ?rand ...))

((letrec ((?lhs ?rhs) ...) ?body) ?rand ...)
===> (letrec ((?lhs ?rhs) ...)
       (?body ?rand ...))

((letrec ((?lhs ?rhs) ...) ?body) ?rand ...)
===> (letrec* ((?lhs ?rhs) ...)
       (?body ?rand ...))

17.9.2 Examples of bindings integration