anchor.diff:  strip_leading_slashes([$/|Rest]) -> strip_leading_slashes(Rest);
   strip_leading_slashes([$\\|Rest]) -> strip_leading_slashes(Rest);
   strip_leading_slashes(RelativePath) -> RelativePath.
  +
  +strip_prefix(Prefix, Path) ->
  +    case lists:split(length(Prefix), Path) of
  +        {Prefix, Stripped} -> {ok, Stripped};
  +        _ -> error
  +    end.
   
   serve_file(File) ->
       {Info, Path} = resolved_file_info(File),
  
positive.code: create_app(Dir) ->
      fun(Env) -> ?MODULE:serve_file(Dir, Env) end.
  
  serve_file(Dir, Env) ->
      serve_file(requested_path(Dir, Env)).
  
  requested_path(Dir, Env) ->
      filename:join(Dir, relative_request_path(Env)).
  
  relative_request_path(Env) ->
      strip_leading_slashes(request_path(Env)).
  
negative.code: -module(psycho_static).
  
  -export([create_app/1, create_app/2,
           serve_file/1, serve_file/2, serve_file/3]).
  
  -include_lib("kernel/include/file.hrl").
  -include("http_status.hrl").
  