3 ms·

I think it only iterates over the collection once.

• rymohr 12y ago
  That and they're collection agnostic. I highly recommend watching Rich Hickey's talk for more background: https://www.youtube.com/watch?v=6mTbuzafcII https://www.youtube.com/watch?v=6mTbuzafcII
• msoad 12y ago
  Then what happens to operations that access the collection? like third argument in JavaScript's native forEach?
  • aeflash 12y ago
    It's not supported. But if you're doing things right, you shouldn't need it.
  • acjohnson55 12y ago
    That's what a zipper [1] is good for. It gives you access to the rest of a collection relative to the current position. [1] http://en.wikipedia.org/wiki/Zipper_%28data_structure%29 http://en.wikipedia.org/wiki/Zipper_%28data_structure%29