anchor.diff:    !---------------------------------------------------------------------------------------------------------------------------------
     endfunction create_tag_flat
   
  -  function create_tag_nested(name, content, attribute, attributes, attributes_stream, indent, is_content_indented) result(tag)
  +  pure function create_tag_nested(name, content, attribute, attributes, attributes_stream, indent, is_content_indented) result(tag)
     !---------------------------------------------------------------------------------------------------------------------------------
     !< Return an instance of xml tag with value being a nested tag.
     !<
  
positive.code:   !---------------------------------------------------------------------------------------------------------------------------------
    endsubroutine parse
  
    subroutine set(self, name, attribute, attributes, attributes_stream, content, indent, is_content_indented, is_self_closing)
    !---------------------------------------------------------------------------------------------------------------------------------
    !< Set tag data.
    !---------------------------------------------------------------------------------------------------------------------------------
  
negative.code: !-----------------------------------------------------------------------------------------------------------------------------------
  contains
    ! creator procedures overloading *xml_tag* name
    pure function create_tag_flat(name, attribute, attributes, attributes_stream, content, indent, &
                                  is_content_indented, is_self_closing) result(tag)
    !---------------------------------------------------------------------------------------------------------------------------------
    !< Return an instance of xml tag.
  