// "optPar int bla = 5;" => "int bla = optPar bla(_, 5);"
svoid tok_optPar(LS tok) {
  if (!tok.contains("optPar")) ret;
  
  int i;
  
  while ((i = jfindOneOf(tok, "optPar <id> <id>", "optPar <id> <")) >= 0) {
    int iEquals = indexOf(tok, "=", i);
    int iSemicolon = tok_findEndOfStatement(tok, iEquals)-1;
    S var = tok.get(iEquals-2);
    clearTokens(tok, i, i+2); // drop optPar
    tok.set(iEquals, "= optPar " + var + "(_, ");
    tok.set(iSemicolon, ");");
    reTok(tok, i, iSemicolon+1);
  }
}