anchor.diff:    attribute_attr_name (attribute_attr_name)*
   ;
   
  +// ----------------------------------------
  +// -------------- Link Header -------------
  +// ----------------------------------------
  +/*
  +ABNF representation of category from the http rendering specification
  +
  +Link specification for links in general:
  +
  +  Link             = "Link" ":" #link-value
  +  link-value       = "<" URI-Reference ">"
  +                    ";" "rel" "=" <"> resource-type <">
  +                    [ ";" "self" "=" <"> link-instance <"> ]
  +                    [ ";" "category" "=" link-type ]
  +                    *( ";" link-attribute )
  +  term             = token
  +  scheme           = URI
  +  type-identifier  = scheme term
  +  resource-type    = type-identifier *( 1*SP type-identifier )
  +  link-type        = type-identifier *( 1*SP type-identifier )
  +  link-instance    = URI-reference
  +  link-attribute   = attribute-name "=" ( token | quoted-string )
  +  attribute-name   = attr-component *( "." attr-component )
  +  attr-component   = LOALPHA *( LOALPHA | DIGIT | "-" | "_" )
  +
  +Link specification for links that call actions:
  +
  +  Link             = "Link" ":" #link-value
  +  link-value       = "<" action-uri ">"
  +                    ";" "rel" "=" <"> action-type <">
  +  term             = token
  +  scheme           = URI
  +  type-identifier  = scheme term
  +  action-type      = type-identifier
  +  action-uri       = URL "?" "action=" term
  +*/
  +//TODO action links spec
   link_header:
     LINK_HEADER  link_path rel (self | link_category)* attributes_attr?
   ;
  
positive.code:   CLOSE_PATH = '>';
  }
  
  occi_header:
      category_header
    | link_header
  
negative.code: 
  
  // ----------------------------------------
  // -------- X-OCCI-Attribute Header--------
  // ----------------------------------------
  /*
  
  