为什么Data.Sequence没有`insert'或`insertBy',我该如何有效地实现它们呢? [英]Why doesn't Data.Sequence have `insert' or `insertBy', and how do I efficiently implement them?
为什么Data.Sequence中缺少takeR,dropR和splitAtR? [英]Why are takeR, dropR and splitAtR missing from Data.Sequence?