anchor.diff:  %%--------------------------------------------------------------------
   %% Function: to_norm(Params)
   %%           Params = list() of string(), each string is a "name=val" 
  -%%           pair or a single "name" value and may contain %HH hex 
  -%%           escape codes - they are treated as case insensetive
  +%%                    pair or a single "name" value and may contain
  +%%                    %HH hex escape codes - they are treated as case
  +%%                    insensitive
   %% Descrip.: convert a uri-parameter list to a normalized (a non case 
   %%           sensitive form) form
   %% Returns : url_param record() | 
  
positive.code: %% Function: add(UrlParam, Key, Value)
  %%           add(UrlParam, Key)
  %%           UrlParam = url_param record(), the record to update
  %%           Key      = string(), treated as case insensetive
  %%           Value    = string(), treated as case insensetive
  %% Descrip.: add new entry or replace old entry in url_param. Key and
  %%           Value are stored in a case insensetive manner
  %% Returns : url_param record()
  %%--------------------------------------------------------------------
  add(UrlParam, Key) ->
  
negative.code: %--------------------------------------------------------------------
  %% Function: find(Param, Key)
  %%           Param = url_param record(), the record to update
  %%           Key   = string(), is treated as case insensitive
  %% Descrip.: retrive the value of Key if it is contained in Param
  %% Returns : [string()] | []
  %%--------------------------------------------------------------------
  