At Sat, 3 Oct 2009 08:34:03 -0600, Matthew Flatt wrote: > (while the contract on the "checked" version ensures that the unsafe > operations will not cause a crash).
Not true. Sam points out that a vector (or other sequence) can be mutable, so checking elements at the beginning does not make `variance' safe if it uses unsafe operations on the elements internally. _________________________________________________ For list-related administrative tasks: http://list.cs.brown.edu/mailman/listinfo/plt-dev
