anchor.diff:  ]).
   
   -export([
  -   lookup_by_rdf_id/1,
  -   lookup_by_lang_string/1
  +   rdf_id/1,
  +   rdf_lang_string/1
   ]).
   
   %%
  
positive.code:    } = eval("test(rdf:id, foaf:name) :- foaf:person(rdf:id, foaf:name, _, _), rdf:id = \"person:149\" . ").
  
  %%
  lookup_by_lang_string(_Config) ->
     #{
        '@type'     := test,
        'rdf:id'    := <<"person:137">>,
  
negative.code: %%%----------------------------------------------------------------------------   
  
  %%
  rdf_id(_Config) ->
     #{
        '@type'     := test,
        'rdf:id'    := <<"person:149">>,
  