----------------------
-- mkWWstr_one wrap_arg = (work_args, wrap_fn, work_fn)
-- * wrap_fn assumes wrap_arg is in scope,
-- brings into scope work_args (via cases)
-- * work_fn assumes work_args are in scope, a
-- brings into scope wrap_arg (via lets)
----------------------
-- mkWWstr_one wrap_arg = (work_args, wrap_fn, work_fn)
-- * wrap_fn assumes wrap_arg is in scope,
-- brings into scope work_args (via cases)
-- * work_fn assumes work_args are in scope, a
-- brings into scope wrap_arg (via lets)