static L<GazelleTree> dm_gazelle_reasonAboutChatInput_v2(S userName, S content, O... _) {
  // GATHER PARAMETERS & CONTEXT
  
  bool debug = boolPar debug(_);
  bool debugRules = boolPar debugRules(_) || debug;
  LS preContext = cast optPar preContext(_);
  GazelleEvalContext ctx = cast optPar ctx(_);
  F0<GazelleEvalContext> contextMaker = cast optPar contextMaker(_);
  if (ctx == null && contextMaker != null) {
    ctx = contextMaker!;
    if (debugRules) print("Called contextMaker, got " + n2(ctx.engine.rules, "rule"));
  }
  if (ctx == null) ctx = dm_gazelle_stdEvalContext(dm_gazelle_allRulesWithComment(optPar requiredComment(_, "discord")));
  Set<S> acceptablePurposes = cast optPar acceptablePurposes(_);

  if (debug)
    print(" == PROCESSING INPUT: " + content);
    
  // PREPARE RULES
    
  // Need input as first condition
  ctx.engine.dropRulesWhere(r -> cicOneOf(r.comments, "in 1 = statement", "in = statement", "disable"));
  
  if (acceptablePurposes != null) {
    if (debugRules) print("Purposes: " + acceptablePurposes);
    ctx.engine.dropRulesWhere(r -> !acceptablePurposes.contains(unnull(r.purpose)));
    if (debugRules) print("Retaining " + n2(ctx.engine.rules, "rule"));
  }
    
  if (debugRules) print("Have rules: " + collect globalID(ctx.engine.rules));
  
  gazelle_addHelpers(ctx, _);
  
  // MAKE PARAMETERS
  
  O[] params = litparams(firstConditionOnly := true, dialogHistory := preContext, +debug,
    badComments := optPar badComments(_),
    acceptablePurposes := optPar acceptablePurposes(_),
    respondingToHuman := optPar respondingToHuman(_),
    skipSplitters := optPar skipSplitters(_));
    
  // TREE1 (just input)
  
  GazelleTree tree1 = cast optPar tree(_);
  if (tree1 == null) tree1 = GazelleTree(ctx, content);
  L<GazelleTree> l = dm_gazelle_getChildren(tree1, params);
  
  // ADDITIONAL MATCHES FOR TREE1
  
  SS inputMap = gazelle_inputMapFromLineAndHistory(content, 
    listPlus(preContext, content));
  if (debug) print("reasonAbout inputMap=" + sfu(asTreeMap(inputMap)));
  dm_gazelle_matchAdditionalInput3(l, inputMap, _);
  
  // TREE2 (user says: ...)
  
  if (nempty(userName) && !boolPar skipUserName(_)) {
    GazelleTree tree2 = new(ctx, optCurly(userName) + " says: " + content);
    if (debug) print("Tree2: " + tree2);
    l.addAll(dm_gazelle_getChildren(tree2, paramsPlus(_, tree2 := true));
  }
  
  // TREE3 (user with id x says: ...)
  
  Long userID = cast optPar userID(_);
  
  if (userID != null && userID != 0 && !boolPar skipUserID(_)) {
    GazelleTree tree3 = new(ctx, "user with id " + userID + " says: " + content);
    l.addAll(dm_gazelle_getChildren(tree3, paramsPlus(_, tree3 := true));
  }
  
  // DROP BAD ENTRIES, SORT
  
  if (boolPar skipBad(_, true)) l = [GazelleTree t : l | neq(t.prediction, 'bad)];
  gazelle_sortChildren(l);
  
  // MATCH ADDITIONAL STATEMENTS
  
  dm_gazelle_matchStatements_v2(l, passParams(_, 'debug, 'dm_gazelle_matchStatementsDebug));
  for (GazelleTree t : l) t.flush();
  
  // DROP UNSATISFIED ENTRIES
    
  int n = l(l);
  l = gazelle_dropUnsatisfiedEntries(l);
  if (debug) print("Filtered out " + (n-l(l)) + " unsatisfied entries (keeping " + l(l) + ")");
  
  // DROP DEFAULTS
  
  if (!boolPar keepDefaults(_))
    gazelle_dropMatchedDefaultRules(l, _);

  ret l;
}