OpenEuphoria

Or instead of a routine-id, something that can be passed to call_func() that works. Here's my solution:

-- wrap the built-in call_func function 
function old_call_func(integer id, sequence args) 
  return call_func(id, args) 
end function 
 
-- override built-in call_func to accept an object as the routine-id 
global function call_func(object id, sequence args={}) 
  if sequence(id) then 
    for i = length(id) to 1 by -1 do 
      args = { call_func(id[i], args) } 
    end for 
    return args[1] 
  end if 
  return old_call_func(id, args) 
end function 
 
-- compose two routine-ids into a sequence that can be used with the above call_func 
global function compose(object f, object g) 
  return {f,g} 
end function 

The overriding call_func function here would need to be defined before including any libraries you would want to call with composed routine-ids.