akhudek/fast-zip — pull request #8 by dthume (2014-10-26 17:58:04+00:00)
Title: Remove redundant calls to up inside next

`next` currently calls `up` multiple times depending on the execution path, which in turn results in multiple calls to `make-node`. While this doesn't make a substantial difference to the performance of `vector-zip`, custom zippers in which `make-node` is more expensive benefit from removing the redundant calls.