static S ai_sfCommands(S s) {
  new Matches m;
  if (swic_trim(s, "!sfargs ", m))
    ret joinWithComma(allToString(numbersOfStandardFunctionArguments(m.rest())));
    
  if (swic_trim(s, "!callsf ", m)) {
    S name = m.rest();
    assertIdentifier(name);
    if (ai_hasTriple("Standard function " + name, "is", "safe to call"))
      ret sfu(callAndMake(name));
  }
    
  null;
}