static void sblock(int d, js_Ast *list)
{
	ps("[\n");
	in(d+1);
	while (list) {
		assert(list->type == AST_LIST);
		snode(d+1, list->a);
		list = list->b;
		if (list) {
			nl();
			in(d+1);
		}
	}
	nl(); in(d); pc(']');
}