sclass RuleEngine2_MatchedRule {
  S globalID = aGlobalID();
  RuleEngine2.Rule rule;
  int iCond;
  SS map;
  new Map<S, Int> mappingQuality; // key in map to -1, 0 or 1
  new LPair<LS> matchedLines;
  S tokenizationFunction;
  LS remainingConditions;
  L<TextAndType> remainingConditionsWithType;
  Int qualitySum;
  Int nPossibleVars;
  S out;

  int qualitySum() {
    if (qualitySum == null)
      qualitySum = intSum(values(mappingQuality))-l(map);
    ret qualitySum;
  }
  
  int nPossibleVars() {
    if (nPossibleVars == null)
      nPossibleVars = l(possibleVars());
    ret nPossibleVars;
  }
  
  bool isSpecialRule() {
    ret rule instanceof RuleEngine2.SimplifyWithRule;
  }
  
  double relativeQuality() {
    ret isSpecialRule() ? 0 : doubleRatio(qualitySum(), nPossibleVars());
  }
  
  // counts all tokens
  Set<S> possibleVars() {
    ret asCISet(codeTokens(tokenize(first(rule.in))));
  }
  
  RuleEngine2.Rule applyMapping() {
    new RuleEngine2.Rule r;
    r.in = map(rule.in, f<S, S> applyMappingTo);
    r.out = applyMappingTo(rule.out);
    ret r;
  }
  
  S appliedRuleText() {
    ret applyMapping().asText();
  }
  
  S applyMappingTo(S s) {
    ret s == null ? null : join(ai_mapCodeTokensWithMap(tokenize(s), map));
  }
  
  LS tokenize(S s) {
    ret (LS) callAndMake(assertNotNull(tokenizationFunction), s);
  }
  
  bool moreConditions() { ret iCond < l(rule.in); }
  
  S ruleID() { ret rule.globalID; }
}