A Rust version for fractional-indexing . Keys in string and satisfy lexicographic order.
Rewritten from existed codebase:
Docs.
use lexicon_fractional_index::key_between;
// create an initial key
let k0 = key_between(&None, &None)?;
// two keys, notice that some strings are not valid keys
let left = "Xb0M".to_owned();
let right = "Xb0M0V".to_owned();
// new key at beginning
let next = key_between(&None, &Some(right.to_owned()))?;
// new key at end
let next = key_between(&Some(left.to_owned()), &None)?;
// new key between 2 keys
let next = key_between(&Some(left.to_owned()), &Some(right.to_owned()))?;
TODO