anchor.diff:  
   
   %% @doc Convert (almost) any value to an atom.
  --spec to_atom(term()) -> atom().
  +-spec to_atom(term()) -> atom() | undefined.
   to_atom(<<>>) -> undefined;
   to_atom([]) -> undefined;
   to_atom(A) when is_atom(A) -> A;
  
positive.code:           clean_lower/1,
            to_list/1,
            to_flatlist/1,
            to_atom/1, 
            to_binary/1, 
            to_binary/2, 
            to_integer/1,
            to_float/1,
            to_bool_strict/1,
  
negative.code: %% Licensed under the Apache License, Version 2.0 (the "License");
  %% you may not use this file except in compliance with the License.
  %% You may obtain a copy of the License at
  %%
  %%     http://www.apache.org/licenses/LICENSE-2.0
  %%
  %% Unless required by applicable law or agreed to in writing, software
  %% distributed under the License is distributed on an "AS IS" BASIS,
  %% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  