lsym_comma
case lsym_comma: process_comma(); break;
if (ps.prev_lsym == lsym_comma
&& (ps.prev_lsym == lsym_comma || ps.prev_lsym == lsym_binary_op))
&& ps.prev_lsym == lsym_comma
case ',': lsym = lsym_comma; next_unary = true; break;