anchor.diff:  
   %% @doc Reconstruct HTTP URL from fragments.
   %%   The tuple is compatible with the one returned by {@link parse/1}.
  +%% @see form/5
   %%
   %% @spec form(url_spec()) ->
   %%   url()
  
positive.code: -export([parse/1]).
  -export([form/1, form/2, form/4, form/5]).
  -export([url_spec/1, url_spec/2, url_spec/4, url_spec/5]).
  
  %% raw URL and URL broken into parts
  -export_type([url/0, url_spec/0]).
  
negative.code: form(Protocol, Host, Port, Path) ->
    form(Protocol, none, Host, Port, Path).
  
  %% @equiv form(Protocol, none, Host, Port, Path)
  %% @see   form/5
  %%
  %% @spec form(hostname(), portnum() | default) ->
  %%   url()
  