svoid tok_swappableFunctions(LS tok) {
  int i;
  while ((i = jfind(tok, "swappable <id> <id>(")) >= 0) {
    S returnType = tok.get(i+2), name = tok.get(i+4);
    int iCurly = indexOf(tok, i, "{");
    LPairS args = tok_typesAndNamesOfParams(subList(tok, i+7, iCurly-2));
    S args2 = joinWithComma(pairsB(args));
    S typeParams = joinWithComma(itemPlusList(returnType, pairsA(args))); // TODO: modifiers, primitives etc.
    S base = name + "_base";
    replaceTokens_reTok(tok, i, iCurly+1, "transient IF\*l(args)*/<\*typeParams*/> \*name*/;\n" + 
      "\*returnType*/ \*name*/() { ret \*name*/ != null ? \*name*/.get(\*args2*/) : \*base*/(\*args2*/); }\n" +
      "\*returnType*/ \*base*/() {");
  }
}