object

# `zlist`

Zipper list predicates. Zippers should be regarded as opaque terms.

Author: Paulo Moura
Version: 1.01
Date: 2019/3/12
Compilation flags:
`static, context_switching_calls`
Implements:
`public` zipperp

## Public interface

### `zip_at_index/4`

Adds a zipper to a list opened at the given index and also returns the element at the index. Fails if the list is empty or the index (starting at 1) does not exist.

Compilation flags:
`static`
Template:
`zip_at_index(Index,List,Zipper,Element)`
Mode and number of proofs:
`zip_at_index(+natural,+list,--zipper,--term)` - `zero_or_one`

## Protected interface

(see related entities)

## Private predicates

(see related entities)

## Operators

(none)

## Remarks

(none)