(.module:
  [lux (#- Scope)
   [abstract
    ["." monad (#+ do)]]
   [data
    ["." product]
    [text
     ["%" format (#+ format)]]
    [collection
     ["." list ("#@." functor)]]]
   [target
    ["_" ruby (#+ Expression)]]]
  ["." // #_
   [runtime (#+ Operation Phase)]
   ["#." case]
   ["#/" //
    ["#/" //
     [//
      [synthesis (#+ Scope Synthesis)]]]]])

(def: #export (scope generate [start initsS+ bodyS])
  (-> Phase (Scope Synthesis) (Operation (Expression Any)))
  (do ////.monad
    [@loop (:: @ map (|>> %.nat (format "loop") _.local) ///.next)
     initsO+ (monad.map @ generate initsS+)
     bodyO (///.with-anchor @loop
             (generate bodyS))]
    (wrap (|> (_.return bodyO)
              (_.lambda (#.Some @loop)
                   (|> initsS+
                       list.enumerate
                       (list@map (|>> product.left (n/+ start) //case.register))))
              (_.apply/* initsO+)))))

(def: #export (recur generate argsS+)
  (-> Phase (List Synthesis) (Operation (Expression Any)))
  (do ////.monad
    [@scope ///.anchor
     argsO+ (monad.map @ generate argsS+)]
    (wrap (_.apply/* argsO+ @scope))))