Crate granular_id

source ·
Expand description

This crate contains the type GranularId, which is a data type which can provide ID numbers in a sequential order, where between any two ID:s, there are infinitely many more granular ID:s. You can think of this as version numbers with an infinite granularity, so if there are versions 1 and 2, there are ID:s 1.1, 1.2, 1.3 etc in-between them. Additionally, in-between ID 1.1 and 1.2, there are infinitely many ID:s 1.1.1, 1.1.2 and so on.

GranularIds is best used with any unsized integer type, where each component of the ID:s may range from the minimum bound to the maximum bound of that integer type. The GranularId that starts with the upper bound of the integer type is the very maximum GranularId. This means that, using u8, all these GranularId<u8>s exist, in increasing order:

  • 254
  • 254.0
  • 254.1
  • 254.1.0
  • 254.1.1
  • 254.1.*
  • …
  • 254.2
  • 254.3
  • 255 255 is the highest ID available of this type (i.e. there is no 255.0, 255.1 etc), and is the upper bound for this type. This constraint is added so that there is an upper bound to the GranularId<T> type if T has an upper bound.

Even though it is recommended to use unsized integers for ID components, any types conforming to the appropriate num_traits may be used.

You may also think of the ID:s as a tree structure, where 3 has the children 3.0, 3.1 etc up to 3.T::max, and 5.3 having the siblings 5.4, 5.5, 5.6 etc following it. For this reason, GranularId<T>::children, GranularId<T>::next_siblings, GranularId<T>::previous_siblings and GranularId<T>::all_siblings, as well as GranularId<T>::parent exist. If you were to build a tree structure, you may have a root ID from which you assign all nodes living in the root ID:s from the children of that root, and in turn assign each child of each children an ID derived from its own ID. In that way, you are maintaining a total ordering of the children (assuming the component type is totally ordered) while being able to easily find the parent ID of any node. The root ID is a special ID since it doesn’t have any components, and is always the lowest ID.

Structs

  • Ancestors
  • BackSequentialIds
  • GranularId
    The data type GranularId represents any ID which can have an arbitrary granularity, meaning that there is indefinitely many GranularIds in-between any two GranularIds. It is best used with unsized integer types such as u8, u16, u32, u64 and usize, but may be used with other data types implementing the required num_traits bounds.
  • SequentialIds

Traits