mapping filter_mapping( mapping map, string fun, object ob, mixed
extra, ... );
mapping map_mapping( mapping map, function f, mixed extra, ... );
映射 filter_mapping( 映射 map, 字符串 fun, 物件 ob, 混合 extra, ...
);
映射 filter_mapping( 映射 map, 函数 f, 混合 extra, ... );