Load JavaScript functions synchronously just-in-time. This is just a concept. This is not ready and I haven't even tried running this.

caller.coffee

myObject =
  myFunction: loadFunction 'myModule/myFunction', this

loader.coffee

loadFunction = (path, self) ->
  (args...) ->
    functionDoesntExist = not window.myNamespace?.myModule?.myFunction?
    if functionDoesntExist
      scriptSrc = loadScriptSrc path
      scriptTag = """<script type="text/javascript">#{scriptSrc}</script>"""
      document.write scriptTag
    # TODO bind self
    window.myNamespace.myModule.myFunction args...
    

loadScriptSrc = (path) ->
  pathElements = path.split('/')
  # TODO get rid of dependency on _
  _.reduce(
    pathElements
    (currentPath, pathElement) -> currentPath[pathElement]
    loadableFunctions
  )

loadableFunctions =
  myModule:
    myFunction: "window.myNamespace.myModule.myFunction = function() {};"