Yes, I just know subseq. And there are also seq-subseq, seq-take, seq-drop, butlast, Two many and hard to remmber.
Almost all of them are implemented in lisp except copy-sequence which is in C. Some of them are implemented
by copying the whole sequence and then modify the copy. If we add the two args to copy-sequence,
then these functions can be based on it with only one or two lines in lisp, and reduce some data copy.
Does the two args make copy-sequence too much complex internally?
在 2017-12-15 16:24:50,"Elias Mårtenson" <address@hidden> 写道: