anchor.diff:  observationsList: observation | observationsList ',' observation;
   observation: '(' fluent ',' time ')';
   
  -
  +queries: query | queries '\n' query;
   query
     : question fluent AT time WHEN scenarioId
     | question PERFORMED action AT time WHEN scenarioId
  
positive.code: TYPICALLY: 'typically';
  WHEN: 'when';
  
  
  typicallyCauses: TYPICALLY causes;
  typicallyInvokes: TYPICALLY invokes;
  typicallyReleases: TYPICALLY releases;
  typicallyTriggers: TYPICALLY triggers;
  
  initiallisation: INITIALLY fluentsList;
  causes: action CAUSES fluentsList underCondition;
  
negative.code: action: actor task;
  fluentsList: fluent | fluentsList ',' fluent;
  
  scenariosList: scenario | scenariosList '\n' scenario;
  scenario: id '{' actions ',' observations '}';
  
  actions: ACS '=' '{' eventsList '}';
  