## Generic-function: SB-SEQUENCE:ITERATOR-STEP
[![package](https://img.shields.io/badge/Package-SB--SEQUENCE-5f9ea0.svg?style=social&colorA=999999)](../) [![type](https://img.shields.io/badge/Type-Generic--Function-5f9ea0.svg?style=social&colorA=999999)](../#generic-function) 

> Moves ITERATOR one position forward or backward in SEQUENCE
> depending on the iteration direction encoded in FROM-END.

### Lambda list
```cl
(sequence sb-impl::iterator sb-impl::from-end)
```