reinh

-- The meta-circular interpreter from section 5 of Reynolds's Definitional
-- Interpreters for Higher Order Programming Languages
-- (http://www.cs.uml.edu/~giam/91.531/Textbooks/definterp.pdf)

data EXP
  = CONST Const
  | VAR Var
  | APPL Appl
  | LAMBDA Lambda
  | COND Cond

tenderlove

cons = fn (a, b) -> fn x -> x.(a, b) end end
car  = fn (p)    -> p.(fn (q, _) -> q end) end
cdr  = fn (p)    -> p.(fn (_, q) -> q end) end
each = fn (list, func) -> 
  iter = fn (list, func, next) ->
    (fn (a, nil) -> func.(a)
        (a, b)   -> func.(a); next.(b, func, next)
    end).(car.(list), cdr.(list))
  end
  iter.(list, func, iter)