使map-indexed的外部接口与map保持一致。map-indexed的现有用法在实现和接口上均未改变。
(map vector (range 10 20) (range 30 35));=> ([10 30] [11 31] [12 32] [13 33] [14 34]) (map-indexed vector (range 10 20) (range 30 35));=> ([0 10 30] [1 11 31] [2 12 32] [3 13 33] [4 14 34])
补丁: CLJ-1601 map-indexed及测试 8-5-2017.patch - 还添加了map-indexed的测试
预审: Alex Miller