* freed on shimmering.
     *
     * Think for example to this:
     *
     * set x {llength $x; ... some more code ...}; eval $x
     *
     * In order to preserve the internal rep, we increment the
     * inUse field of the script internal rep structure. 
     */
    script.in_use++;
    token = script.script_object.tokens;
    /* Execute every command sequentially until the end of the script
     * or an error occurs.
     */
    for (i = 0; i < script.len && retcode == stmt.OK; ) {
      var argc;