Question

A function takes a sequence as the parameter. In the function, I want to make an empty sequence of the same type of the parameter. Then I’ll store something and return it such that the return type is the same as the parameter. But

(make-sequence (type-of parameter) 0) will cause error if parameter is any list or vector of some length.

My current solution is:
1. use an empty list to store things, let’s call it temp-list
2. (make-sequence (type-of parameter) (length temp-list))
3. copy the elements, then return

Other better solutions?

Answer 1

returning an empty sequence of the same type

(subseq sequence 0 0)