anchor.diff:  attr: attr_name (value | NAME)+
   
   attr_name: NAME | composite_type
  -?value: string | int | float | expression | not_expression | attr_bind | path | regexp | runtime_var | list | bare_string2
  +?value: string | int | float | expression | not_expression | attr_bind | path | regexp | runtime_var | list | bare_string2 | NULL
   
   int: SIGNED_INT
   int_pair: int int
  
positive.code: 
  %ignore COMMENT
  %ignore CCOMMENT
  %ignore WS
negative.code: AUTO: "AUTO"i
  PATH: /([a-z0-9_]*\.*\/|[a-z_]+[.\/])[a-z0-9_\/\.]+/i
  NAME: /[a-z_][a-z0-9_]*/i
  NULL: "NULL"i
  
  SIGNED_FLOAT: ["-"|"+"] FLOAT
  SIGNED_INT: ["-"|"+"] INT
  