destructively. See @ref{Sets And Lists}.
@end defun
+@defun number-sequence from to &optional separation
+This returns a list of numbers starting with @var{from}
+and incrementing by @var{separation} (or by 1 if @var{separation}
+is @code{nil} or omitted), and ending at or just before @var{to}.
+For example,
+
+@example
+(number-sequence 4 9)
+ @result{} (4 5 6 7 8 9)
+(number-sequence 1.5 6 2)
+ @result{} (1.5 3.5 5.5)
+@end example
+@end defun
+
@node Modifying Lists
@section Modifying Existing List Structure
@cindex destructive list operations