Flesh out functionality

[FintanH]

We should flesh out the functionality of nonempty. A lot of it would just be the Vec implementation. Enumerating these for clarity and also to comment on which ones we may not want:

• [x] append
• [x] ~~as_mut_ptr~~ N/A (memory is not contiguous)
• [x] ~~as_mut_slice~~ N/A
• [x] ~~as_ptr~~ N/A
• [x] ~~as_slice~~ N/A
• [x] capacity
• [ ] chunks
• [ ] chunks_exact
• [ ] chunks_exact_mut
• [ ] chunks_mut
• [x] clone_from_slice - ~we use from_slice, we should rename~ This doesn't make sense either since it's just copying a slice's contents in, but we can't guarantee a length of 1 without panicing.
• [ ] concat
• [ ] connect
• [x] contains
• [x] copy_from_slice - ~we have from_slice but a Copy version would be good~ Looking into the semantics of this, I think it doesn't suit NonEmpty after all.
• [ ] copy_within
• [ ] clear - we probably don't want this
• [ ] dedup
• [ ] dedup_by
• [ ] drain - wouldn't make sense for NonEmpty unless it returned a Vec rather than Drain
• [ ] drain_filter - same as above
• [ ] ends_with
• [ ] eq_ignore_ascii_case
• [ ] extend_from_slice
• [x] first
• [x] first_mut
• [ ] from_raw_parts - this seems unecessary
• [x] get
• [x] get_mut
• [ ] get_unchecked
• [ ] get_unchecked_mut
• [x] insert
• [x] into_boxed_slice
• [ ] into_raw_parts - not sure about this one
• [ ] is_ascii
• [x] is_empty
• [ ] is_sorted
• [ ] is_sorted_by_key
• [x] iter
• [x] iter_mut
• [ ] join
• [x] last
• [x] last_mut
• [ ] leak - seems specialised
• [x] len
• [ ] make_ascii_lowercase
• [ ] make_ascii_uppercase
• [x] new
• [ ] partition_at_index
• [ ] partition_at_index_by
• [ ] partition_at_index_by_key
• [ ] partition_deup
• [ ] partition_deup_by
• [ ] partition_deup_by_key
• [x] pop
• [x] push
• [ ] rchunks
• [ ] rchunks_exact
• [ ] rchunks_exact_mut
• [ ] rchunks_mut
• [ ] remove - should give back Vec
• [ ] remove_item - should give back Vec
• [ ] repeat
• [ ] reserve
• [ ] reserve_exact
• [ ] resize - possibly just work on the tail Vec
• [ ] resize_default
• [ ] resize_wtih
• [ ] retain - unsure if this should be kept
• [ ] reverse
• [ ] rotate_left
• [ ] rotate_right
• [ ] rsplit
• [ ] rsplit_mut
• [ ] rsplitn
• [ ] rsplitn_mut
• [ ] set_len
• [ ] shrink_to - should be greater than 1
• [ ] shrink_to_fit
• [ ] sort
• [ ] sort_by
• [ ] sort_by_cahced_key
• [ ] sort_by_key
• [ ] sort_unstable
• [ ] sort_unstable_by
• [ ] sort_unstable_by_key
• [ ] splice
• [x] split
• [ ] split_at
• [ ] split_at_mut
• [x] split_first
• [ ] split_first_mut
• [ ] split_last
• [ ] split_last
• [ ] split_last_mut
• [ ] split_mut
• [ ] split_off
• [ ] splitn
• [ ] splitn_mut
• [ ] starts_with
• [ ] swap
• [ ] swap_with_slice
• [ ] to_ascii_lowercase
• [ ] to_ascii_uppercase
• [x] to_vec - the Into impl does this
• [ ] try_reserve
• [ ] try_reserve_exact
• [ ] windows
• [ ] with_capacity
• [ ] From<NonEmpty<T>> for Vec<T> - https://github.com/cloudhead/nonempty/pull/17#issuecomment-600217655

[FintanH]

Hmmmm so something I'd like to discuss is the functions that come "Methods from Deref<Target = [T]>". Is this something that's possible with NonEmpty? Also, this makes me think, could we implement Deref<Target=Vec<T>>? :thinking:

Otherwise, I think the way to go about it is go through the list of functions and see if they're possible to implement.

[FintanH]

As discussed async, we should use https://doc.rust-lang.org/std/num/struct.NonZeroUsize.html for things that take a length, e.g. with_capacity

[FintanH]

Something I'd also be interested in is split functions that own the T, I'm not sure if this is possible though. I tend to split and consume, but I end up having to clone :/

[fritzrehde]

In the checklist it says as_mut_slice is implemented, but I can't find that method anywhere in the repo or in the documentation.

[cloudhead]

I think it's checked for the same reason as_slice is checked: it's actually not possible to implement these since the memory isn't contiguous. I'll update the todo.