anchor.diff:  entities, but generalized for all elements.
   
   Extended names are composed of a string of characters enclosed in single
  -quotes. There is no restrictions on characters within extended names except
  +quotes. There is no restriction on characters within extended names except
   they may not include single quotes or line breaks.
   
   The following elements support extended names:
  
positive.code: and a transition row for the "null state" (designated by the keyword
  "non_existent"). The header row must contain a reference to every event defined
  in the state machine. Each cell of the table must specify the result of
  receiving particular event while in the particular state. A transition result
  can be specified by naming the destination state of the transition. A
  non-transition result can be specified by either "cannot_happen" or "ignore".
  At runtime, a "cannot_happen" results in an error being raised and "ignore"
  
negative.code: 
  Relationships may be simple, associative (linked), or subtype/supertype.
  Relationships do not support extended names and the name of a relationship must
  begin with the character 'R' followed by a positive integer:
  
  Simple relationships are defined by a pair of opposing "half relationships"
  defining the relationship from both directions. Each direction can have a
  