... https://github.com/wlav/cppyy
(.require
 [library
  [lux (.except)
   [program (.only program)]
   ["[0]" ffi (.only import)]
   ["[0]" debug]
   [abstract
    [monad (.only do)]]
   [control
    ["[0]" maybe (.use "[1]#[0]" monad)]
    ["[0]" try (.only Try)]
    ["[0]" exception (.only Exception)]
    ["[0]" io (.only IO io)]
    ["[0]" function]
    [concurrency
     ["[0]" async (.only Async)]]]
   [data
    ["[0]" product]
    [text
     ["%" \\format (.only format)]
     [encoding
      ["[0]" utf8]]]
    [collection
     ["[0]" array (.only Array)]]]
   [math
    [number
     ["n" nat]
     ["i" int]
     ["[0]" i64]]]
   ["[0]" world
    ["[0]" file]
    ["[1]/[0]" environment]]
   [meta
    ["@" target (.only)
     ["_" js]]
    [macro
     ["^" pattern]
     ["[0]" template]]
    [compiler
     [reference
      [variable (.only Register)]]
     [language
      [lux
       [program (.only Program)]
       [translation (.only Host)]
       [analysis
        [macro (.only Expander)]]
       ["[0]" phase (.only Operation Phase)
        ["[0]" extension (.only Extender Handler)
         ["[0]" analysis
          ["[1]" js]]
         ["[0]" translation
          ["[1]" js]]]
        [translation
         ["[0]" reference]
         ["[0]" js (.only)
          ["[0]" runtime]
          ["[1]/[0]" reference]]]]]]
     [default
      ["[0]" platform (.only Platform)]]
     [meta
      ["[0]" cli]
      ["[0]" context]
      [archive (.only Archive)
       ["[0]" unit]]
      ["[0]" packager
       ["[1]" script]]]]]]]
 [program
  ["/" compositor]])

(import cppyy
  "[1]::[0]"
  ("static" cppdef [Text] "io" Bit)
  ("static" gbl (ffi.Object Any)))

(def _
  (program []
    (do io.monad
      [? (cppyy::cppdef ["void say_hello() { std::cout << 123 << std::endl; }"])
       .let [_ (debug.log! (%.format "BEFORE " (%.bit ?)))]
       global (cppyy::gbl)
       .let [say_hello (as ffi.Function
                           (.python_object_get# "say_hello" global))
             _ (debug.log! "AFTER")
             _ (.python_apply# say_hello [])]]
      (in (debug.log! "Hello, C++")))))