svoid tok_metaFor(LS tok) {
  int i;
  
  jreplace(tok, "meta-for <id> also as", "meta-for $4 in $4,");
  
  while ((i = jfind_any(tok,
    "meta-for <id> in",
    "meta-for <id> as")) >= 0) {
    int iOpening = indexOf(tok, i, "{");
    int iClosing = tok_findEndOfBracketPart(tok, iOpening)-1;
    int iVar = i+6, iFirstValue = iVar+4;
    S var = tok.get(iVar);
    LS values = identifiersOnly(subList(tok, iFirstValue, iOpening-1));
    LS body = subList(tok, iOpening+1, iClosing);
    
    tokReplace_reTok(tok, i, iClosing+1,
      mapToLines(values, value ->
        join(replaceInClonedList(body, var, value))));
  }
}