anchor.diff:  @lexer::header {
     package be.edmonds.occi;
   }
  +
   // ----------------------------------------
   // ---------- All OCCI Headers ------------
   // ----------------------------------------
  
positive.code: //TODO action links spec
  //TODO allow for multiple links per line seperated by ','
  link_header:
    LINK_HEADER  link_path rel_attr (self | link_category)* attributes_attr?
  ;
  
  link_path:
    OPEN_PATH link_path_val CLOSE_PATH
  ;
  link_path_val:
    PATH
  ;
  
  self:
    CAT_ATTR_SEP SELF_ATTR VAL_ASSIGN QUOTE self_val QUOTE
  ;
  self_val:
    TOKEN
  ;
  
  link_category:
    CAT_ATTR_SEP CAT_ATTR VAL_ASSIGN QUOTE link_category_val QUOTE
  ;
  link_category_val:
    TOKEN
  ;
  
  attributes_attr:
    (CAT_ATTR_SEP attribute_attr)+
  ;
  attribute_attr:
  
negative.code:   CATEGORY_HEADER category_header_val
  ;
  category_header_val:
    term_attr scheme_attr class_attr (title_attr | rel_attr | location_attr | cat_attributes_attr)*
  ;
  term_attr:
    TOKEN
  