arranges 0.0.4

Mergable range object for use in Pydantic classes

Arranges

Range string fields for Pydantic BaseModels

I needed a way to parse batches of byte, row and line and other object ranges in my merge-files app, in a way that I can just drop it in as a string field type. The reason for this is so the machine-generated command line help is flat and readable by humans.

It it kinda grew into a monster so I've split it out into this separate package. It gives a couple of classes for dealing with ranges:

• Range, a class that can be constructed from Python-style slice notation strings (e.g. "1:10", "0x00:0xff, ":"), range-likes, iterables of int-like objects. It has convenient properties lke being iterable, immutable, has a stable string representation and matching hash, it can be treated like a set and its constructor is compatible with range and slice.
• The Ranges class is similar but supports holes in ranges - it's an ordered, mutable list of non-overlapping Range objects that simplifies as data is added.

Constraints

I made it to select lines or bytes in a stream of data, so it:

• only supports ints;
• does not allow negative indices, the minimum is 0 and the maximum is unbounded;
• it's compatible with range and slice, but step is fixed to 1. This may change in the future;
• does not support duplicate ranges. Ranges are merged together as they are added to the Ranges object;
• it is unpydantic in that its constructors are duck-typed, which is what I need; and
• it violates the Zen of Python by having multiple ways to do the same thing, but it's also useful.
• Currently the interface is unstable, so lock the exact version in if you don't want breaking changes.

Installation

pip install arranges if you want to use it. You'll need Python 3.10 or above.

Dev setup

To add features etc you'll ideally need git, make, bash and something with a debugger. Config for Visual Studio Code is included.

Clone the repo and make dev to make the venv, install dependencies, then code . to open the project up in the venv with tests and debugging and all that jazz.

Type make help to see the other options, or run the one-liner scripts in the ./build dir if you want to run steps without all that fancy caching nonsense.

Usage

• RTFM
• Read the tests, which have full coverage.
• Read the pydocs

License

Free as in freedom from legalese; the WTFPL with a warranty clause.

Political note: I don't want to live in a world where lawyers tell me how to speak. If you don't trust me enough to use the WTFPL then you shouldn't be running my code in the first place.