anchor.diff:  
   %% TODO: replace the use of the unofficial 'write_string/2'.
   
  --spec atom_lit(cerl()) -> string().
  +-spec atom_lit(cerl()) -> nonempty_string().
   
   atom_lit(Node) ->
       io_lib:write_string(atom_name(Node), $'). %' stupid Emacs.
  
positive.code: %%
  %% @see c_char/1
  
  -spec char_lit(c_literal()) -> string().
  
  char_lit(Node) ->
      io_lib:write_char(char_val(Node)).
  
negative.code: %%
  %% @see c_string/1
  
  -spec string_lit(c_literal()) -> nonempty_string().
  
  string_lit(Node) ->
      io_lib:write_string(string_val(Node)).
  