sbool dm_gazelle_matchStep_statement(GazelleTree t, O... _) {

  if (t.rule() == null) false;

  bool debug = boolPar debug(_) || boolPar matchStatementsDebug(_);

  RuleEngine2_MatchedRule mr = t.mr;

  LS in = t.rule().in;

  int iCond = t.mr.iCond;

  if (debug) print("matchStatements: iCond=" + iCond + " in " + in);

  if (iCond >= l(in)) false;

  LS conditions = dropFirst(iCond, in);

  if (debug) print("Remaining conditions for " + t.ruleID() + " with " + t.mr.map + ": " + conditions);

  new Matches m;

  if (!matchAny("in " + (iCond+1) + " = statement *", t.rule().comments, m))

    false;

  S subRuleID = $1;

  if (debug) print("Found subrule: " + subRuleID);

  // load all known fulfillments

  L fulfillments = dm_gazelle_fulfillmentsForRule(subRuleID);

  // find best fulfillment

  new Lowest<SS> bestMap;

  if (debug) print("Have " + n2(fulfillments, "fulfillment") + ".");

  for (O f : fulfillments) {

    SS varMap = asCIMap(safeUnstructMap(getString varMap(f)));

    if (debug) print("fulfillment => " + sfu(varMap));

    // self-vars hack to fix John Doe problem

    bool selfVarsFix = boolPar selfVarsFix(_, true);

    if (selfVarsFix) {

      S cond = first(conditions);

      for (S x : identifiersOnly(codeTokens(mr.tokenize(cond))))

        if (!varMap.containsKey(x)) {

          if (debug) print("Self-linking " + x);

          varMap.put(x, x);

        }

    }

    if (debug) print("Original map: " + t.mr.map);

    SS newMap = mergeMapsStrictlyIC(asCIMap(t.mr.map), varMap);

    if (newMap == null) {

      if (debug) printIndent("Can't merge maps");

      continue;

    }

    if (debug) printIndent("Maps merged! => " + sfu(newMap));

    newMap = ciMapWithoutKeysEqualToValues(newMap);

    if (debug) printIndent("Map simplified => " + sfu(newMap));

    continue if gazelle_isRecentlyUsedMapping(t, newMap, _);

    bestMap.put(newMap, l(newMap));

  }

  SS newMap = bestMap!;

  if (newMap == null) {

    if (debug) print("No matching statement found");

    false;

  }

  t.mr.map = newMap;

  t.mr.iCond++;

  t.mr.remainingConditions = dropFirst(t.mr.remainingConditions); // XX: also should rewrite with new vars

  t.mr.remainingConditionsWithType = dropFirst(t.mr.remainingConditionsWithType);

  t.mr.out = null;

  t.line = t.mr.outText();

  if (debug) print("Rewrote " + t.mr.rule.out + " to: " + t.line);

  true;

}