Inimitable

UUIDs for Scala

UUIDs are a convenient and standardized way to assign IDs, with guarantees that those IDs will be unique, not just within a local system, but globally across all systems. Inimitable provides a few utilities for working with them.

Features

• construct new UUIDs trivially
• check hard-coded UUIDs at compiletime
• parse UUIDs at runtime
• XOR and invert UUIDs

Availability Plan

Inimitable has not yet been published. The medium-term plan is to build Inimitable with Fury and to publish it as a source build on Vent. This will enable ordinary users to write and build software which depends on Inimitable.

Subsequently, Inimitable will also be made available as a binary in the Maven Central repository. This will enable users of other build tools to use it.

For the overeager, curious and impatient, see building.

Getting Started

All Inimitable terms and types are defined in the inimitable package:

import inimitable.*

Constructing a new UUID

A UUID can be constructed with the Uuid() factory method. This will create a new, and by definition, universally unique, identifier. The Uuid instance is composed of two 64-bit longs, msb (for "most significant bits") and lsb ("least significant bits"), implying (in theory) 128 bits of entropy.

Specific UUIDs

A particular UUID, for example e6388c03-3dd2-4044-bb38-e58dbf8368fd, may be constructed using the uuid"" interpolator, like so,

val uuid = uuid"e6388c03-3dd2-4044-bb38-e58dbf8368fd"

which will parse (at compiletime) the UUID hex digits and their format ensuring, in particular, that all are present to represent 128 bits of data.

Additionally, a Uuid can be created at runtime with,

val long1 = 234827342384709201L
val long2 = 928160134367288378L
val uuid2 = Uuid(long1, long2)

which will use the bits from long1 and long2.

Alternatively, a Text string containing a UUID can be parsed using Spectacular's decodeAs extension method:

import spectacular.decodeAs
import gossamer.t
import contingency.errorHandlers.throwUnsafely

val text = t"e6388c03-3dd2-4044-bb38-e58dbf8368fd"
val uuid3 = text.decodeAs[Uuid]

This will raise a UuidError if it is not in the correct format.

Methods on Uuids

Two convenience methods are provided on Uuids:

• the unary ~ operator, which will construct a new Uuid by inverting its bits, and
• the binary ^ operator, which will combine two Uuids by XORing their bits

Status

Inimitable is classified as maturescent. For reference, Scala One projects are categorized into one of the following five stability levels:

• embryonic: for experimental or demonstrative purposes only, without any guarantees of longevity
• fledgling: of proven utility, seeking contributions, but liable to significant redesigns
• maturescent: major design decisions broady settled, seeking probatory adoption and refinement
• dependable: production-ready, subject to controlled ongoing maintenance and enhancement; tagged as version 1.0.0 or later
• adamantine: proven, reliable and production-ready, with no further breaking changes ever anticipated

Projects at any stability level, even embryonic projects, can still be used, as long as caution is taken to avoid a mismatch between the project's stability level and the required stability and maintainability of your own project.

Inimitable is designed to be small. Its entire source code currently consists of 88 lines of code.

Building

Inimitable will ultimately be built by Fury, when it is published. In the meantime, two possibilities are offered, however they are acknowledged to be fragile, inadequately tested, and unsuitable for anything more than experimentation. They are provided only for the necessity of providing some answer to the question, "how can I try Inimitable?".

1. Copy the sources into your own project

   Read the fury file in the repository root to understand Inimitable's build structure, dependencies and source location; the file format should be short and quite intuitive. Copy the sources into a source directory in your own project, then repeat (recursively) for each of the dependencies.

   The sources are compiled against the latest nightly release of Scala 3. There should be no problem to compile the project together with all of its dependencies in a single compilation.

2. Build with Wrath

   Wrath is a bootstrapping script for building Inimitable and other projects in the absence of a fully-featured build tool. It is designed to read the fury file in the project directory, and produce a collection of JAR files which can be added to a classpath, by compiling the project and all of its dependencies, including the Scala compiler itself.

   Download the latest version of wrath, make it executable, and add it to your path, for example by copying it to /usr/local/bin/.

   Clone this repository inside an empty directory, so that the build can safely make clones of repositories it depends on as peers of inimitable. Run wrath -F in the repository root. This will download and compile the latest version of Scala, as well as all of Inimitable's dependencies.

   If the build was successful, the compiled JAR files can be found in the .wrath/dist directory.

Contributing

Contributors to Inimitable are welcome and encouraged. New contributors may like to look for issues marked beginner.

We suggest that all contributors read the Contributing Guide to make the process of contributing to Inimitable easier.

Please do not contact project maintainers privately with questions unless there is a good reason to keep them private. While it can be tempting to repsond to such questions, private answers cannot be shared with a wider audience, and it can result in duplication of effort.

Author

Inimitable was designed and developed by Jon Pretty, and commercial support and training on all aspects of Scala 3 is available from Propensive OÜ.

Name

The name Inimitable describes the core feature of UUIDs: that they are universally unique, and cannot be imitated.

In general, Scala One project names are always chosen with some rationale, however it is usually frivolous. Each name is chosen for more for its uniqueness and intrigue than its concision or catchiness, and there is no bias towards names with positive or "nice" meanings—since many of the libraries perform some quite unpleasant tasks.

Names should be English words, though many are obscure or archaic, and it should be noted how willingly English adopts foreign words. Names are generally of Greek or Latin origin, and have often arrived in English via a romance language.

Logo

The logo shows an arrangement of the 128 bits which form a UUID in a grid.

License

Inimitable is copyright © 2024 Jon Pretty & Propensive OÜ, and is made available under the Apache 2.0 License.