5 Yes, if 'unless' were implemented in an applicative order language, then
6 it would be implemented as a special form and would be translated into
7 other functions before evaluation.
9 Now, if such a special form is used in a higher order function like 'map'
12 (map unless '((p-list) (usual-list) (exception-list)))
14 then, unless gets expanded before evaluation. But map expects a function
15 as its second argument.
17 To see the implementation of unless, see metacircular2.rkt